Jae Keun Oh

Is It Possible to Evaluate the Parameters of Cervical Sagittal Alignment on Cervical Computed Tomographic Scans

Study Design. Retrospective study. Objective. The purpose of this study was to analyze the relationship of the parameters of cervical sagittal alignment between those obtained from cervical CT and those obtained from radiography, as well as to determine which parameter would help predict physiological lordosis of the cervical spine. Summary of Background Data. Sagittal balance in the cervical spine is as important as the pelvic incidence and is related to the concept of T1 slope. However, many articles including this article based on unclear cervical x-ray radiographs could weakly explain the parameters. To overcome the fundamental limitation of x-ray radiographs, Hallym University Sacred Heart Hospital reported the strong correlation between T1 slope and cervical lordosis on the cervical dimensional CT scans like result by checking by the cervical x-ray radiographs. Methods. A retrospective analysis of data from 50 asymptomatic adults in whom both cervical CT scans and cervical radiograph were obtained at the same time. The T1 slope, Cobb angle C2–C7, neck tilt, and thoracic inlet angle (TIA) obtained from the CT scans and radiographs were assessed. Results. The T1 slope on x-ray was significantly correlated with the T1 slope on CT. The mean of the T1 slope on x-ray was larger than the mean of the T1 slope on CT (3.3° ± 6.1°). More cervical spine lordosis was evident on the cervical radiograph than on the cervical CT scan (5.93° ± 9.0°). No significant difference was seen between the TIA on x-ray and the TIA on CT (TIA on x-ray − TIA on CT, −0.1 ± 7.6, P = 0.959). Conclusion. This difference may be due to the differing effect of gravity upon the spine between the upright versus the supine position. Accordingly, TIA and T1 slope may be used as a guide for the assessment of sagittal balance of the cervical spine. Level of Evidence: N/A

Sagittal spinopelvic malalignment in parkinson disease: Prevalence and associations with disease severity

Study Design. Prospective study. Objective. Our objectives were to evaluate the prevalence of sagittal spinopelvic malalignment in a consecutive series of patients with Parkinson disease (PD) and to identify factors associated with sagittal spinopelvic deformity in this population. Summary of Background Data. PD is a degenerative neurological condition characterized by tremor, rigidity, bradykinesia, and loss of postural reflexes. The prevalence of spinal deformity in PD is higher than that of age-matched adults without PD. Methods. This study was a prospective assessment of consecutive patients with PD presenting to a neurology clinic during 12 months. Inclusion criteria included age more than 21 years and diagnosis of PD. Age- and sex-matched control group was selected from patients with cervical spondylosis. Clinical and demographic factors were collected including Unified Parkinson Disease Rating Scale score and Hoehn and Yahr stage. Full-length standing spine radiographs were assessed. Patients were grouped into either low C7 sagittal vertical axis (SVA) (<5 cm) or high C7 SVA (≥5 cm) and into matched (⩽10°) or mismatched (>10°) pelvic incidence (PI)-lumbar lordosis. Results. Eighty-nine patients met criteria (41 males/48 females), including 52 with low C7 SVA and 37 with high C7 SVA. Significantly higher prevalence of high C7 SVA was found in PD (41.6 vs. 16.8%; P < 0.001). The high C7 SVA group was significantly older (72.4 vs. 65.1 yr; P < 0.001) and had a higher proportion of females (68% vs. 44%; P = 0.034), greater severity of PD based on Hoehn and Yahr stage (1.89 vs. 1.37; P < 0.001) and Unified Parkinson Disease Rating Scale (30.5 vs. 17.2; P = 0.002. Unified Parkinson Disease Rating Scale significantly correlated with C7 SVA (r = 0.474). Compared with the matched (⩽10°) PI-lumbar lordosis group, the mismatch PI-lumbar lordosis group had higher C7 SVA, higher PI, higher pelvic tilt, lower lumbar lordosis, and lower thoracic kyphosis (P ⩽ 0.003). Conclusion. Patients with PD have a high prevalence of sagittal spinopelvic malalignment than control group patients. Greater severity of PD is associated with sagittal spinopelvic malalignment. Level of Evidence: 3

Thoracolumbar extradural arachnoid cysts: a study of 14 consecutive cases

BackgroundTo investigate characteristic clinical and radiological features of extradural arachnoid cysts (EDACs) in the thoracolumbar region, a retrospective review of medical records and imaging studies was performed. EDACs are well known but relatively rare lesions in the thoracolumbar spinal canal. The most common site is the lower thoracic spine, and it may cause neurological symptoms by compressing the spinal cord or nerve root. In this study, the pathogenesis, symptomatology, diagnostic approach, and surgical management of EDACs will be discussed.MethodsWe studied 14 consecutive patients who were surgically treated for EDACs in the thoracolumbar region at our institute between March 2000 and January 2011. The history, clinical presentations, image findings, operative findings, and surgical outcomes of these patients were retrospectively analyzed. The mean follow-up period was 28xa0months (range: 6–72xa0months).ResultsProgressive motor weakness was the predominant symptom in all patients. Nine patients had radicular leg pain and back pain in the thoracolumbar area. On MRI, the cyst compressed the dural sac and spinal cord posteriorly typically with bilateral foraminal extensions. On radiological study, a communication point with the subarachnoid was hardly observed. The surgical treatment of EDACs included complete resection of the walls and closing the communicating point with the subarachnoid space. All patients showed excellent outcomes according to Odom’s criteria without recurrence. One CSF leakage and one postoperative hematoma were noted.ConclusionsThoracolumbar EDAC patients presented paraparesis and leg pain. Complete excision and closing the communicating point with the subarachnoid space were the choices of treatment, and the outcomes were favorable.

Intraoperative indocyanine green video-angiography: spinal dural arteriovenous fistula.

Study Design. Technical note. Objective. To describe the use of intraoperative indocyanine green (ICG) video-angiography for obliteration of a spinal dural arteriovenous fistula (DAVF) and to show a video clip. Summary of Background Data. ICG video-angiography is an emerging tool for delineating intraoperative vascular anatomy, and it has a significant potential in the treatment of vascular diseases in the spine. Methods. The authors presented a case of a 73-year-old man with progressive and debilitating bilateral lower extremity weakness. The patient was diagnosed with a spinal DAVF of 10th thoracic spine based on the results of conventional spinal angiography. Results. The patient underwent T9–10 laminotomy for microsurgical clip occlusion. Intraoperative ICG video-angiography was used before clip placement to identify the arterialized veins of the fistula and after clip placement to confirm obliteration of the fistulous connection and restoration of normal blood flow. Conclusion. Intraoperative ICG video-angiography serves an important role in the microsurgical treatment of DAVF. It is simple and provides real-time information about the precise location of spinal DAVF and result after obliteration of spinal DAVF.

Stand-alone cervical cages versus anterior cervical plate in 2-level cervical anterior interbody fusion patients: clinical outcomes and radiologic changes.

Study Design: Retrospective study. Objectives: To compare the efficacy of 2-level anterior cervical discectomy and fusion with cage alone (ACDF-CA) and with cage and plate construct (ACDF-CPC) with regard to clinical outcome and radiologic changes. Summary of Background Data: The use of stand-alone cervical interbody cages in ACDF has become popular, but high subsidence rates have been reported in the literature. Methods: A total of 54 consecutive patients who underwent 2-level ACDF-CA or ACDF-CPC after suffering from cervical radiculopathy were divided into 2 groups: group A (n=28) underwent ACDF-CA, group B (n=26) underwent ACDF-CPC. Fusion rate, global and segmental kyphosis, disk height, and subsidence rate were assessed by radiolographs. Clinical outcomes were assessed using Robinson’s criteria. Results: Solid fusion was achieved in 96.43% (27/28) in group A and in 96.15% (25/26) in group B. Fusion segmental kyphosis of >5 degrees occurred in 14.29% (4/28) of group A and in 7.69% (2/26) of group B; however, there was no statistical difference between the 2 groups (P>0.05). Subsidence occurred in 35.71% (10/28) of group A as compared with 11.54% (3/26) of group B (P<0.05). Clinical outcomes were similar in the 2 treatment groups. Conclusions: The use of cage and plate construct in 2-level ACDF results in a shorter fusion duration and a lower subsidence rate than that of cage alone; however, there is no significant difference in the postoperative global and segmental alignment and clinical outcomes between groups.

Effects of Lumbar Arthrodesis on Adjacent Segments Differences Between Surgical Techniques

Study Design. A finite element analysis. Objective. To evaluate the differences between surgical techniques in terms of the effects of arthrodesis on adjacent segments. Summary of Background Data. Augmentation with posterior rigid fixation combined with transpedicular screw insertion, which is one of the most popular techniques for lumbar arthrodesis, shows benefits in immediate stabilization and a higher fusion rate but is reportedly correlated with greater stress on adjacent segments. However, the increased stress on adjacent segments needs further evaluation because the differences of the effects on adjacent segments between surgical techniques, including anterior lumbar interbody fusion, posterior lumbar interbody fusion, and semirigid fixation, have not yet been determined. Methods. A finite element model of the human lumbar spine was developed. Three spinal segments (L2–L5) were used to investigate. The intact spinal model was validated by comparing it with previously reported models. Then, 4 arthrodesis models were analyzed and compared: (1) anterior lumbar interbody fusion model; (2) posterior lumbar interbody fusion model; (3) semirigid fixation model combined with posterior lumbar interbody fusion; and (4) rigid fixation model combined with posterior lumbar interbody fusion. Results. Among these 4 models, the rigid fixation model showed the greatest amount of stress, with increased intervertebral disc pressure and contact force of the facet joints of both upper and lower adjacent segments. The second highest stress levels were seen in the semirigid fixation model and the lowest stress levels were seen in the anterior lumbar interbody fusion model. Conclusion. Although bony fusion had been completed, the effects of lumbar arthrodesis on adjacent segments could vary according to the surgical technique used for arthrodesis. Semirigid fixation combined with arthrodesis deserves careful consideration and further detailed study because it may cause less stress on adjacent segments than rigid fixation while maintaining the benefits of the latter procedure.

T1 slope and degenerative cervical spondylolisthesis.

Study Design. Retrospective analysis. Objective. The main objectives of this study were to analyze and compare cervical sagittal parameters, including the T1 slope, in a population of 45 patients with degenerative cervical spondylolisthesis (DCS) and to compare these patients with a control group of asymptomatic population. Summary of Background Data. Sagittal balance in the cervical spine is as important as the pelvic incidence and is related to the concept of T1 slope. Compared with degenerative lumbar spondylolisthesis, there are few studies evaluating DCS, and characteristic changes of the cervical sagittal parameters (including T1 slope) in patients with DCS are not well studied. Methods. We identified 45 patients with DCS (5.8%) from a database of 767 patients, using cervical radiograph in a standing position. All had radiograph and computed tomographic scan at the same time. Cervical sagittal parameters were analyzed on computed tomographic scan in a standardized supine position. The following cervical sagittal parameters were measured: T1 slope, neck tilt, thoracic inlet angle, and cervical lordosis (C2–C7 angle). The DCS group was compared with a control group of 45 asymptomatic age- and sex-matched adults to the DCS group, who were studied in a recently published study. Results. Of our initial group of 767 patients, 45 with anterolisthesis (5.8%) were included for this study. The T1 slope was significantly greater for DCS (26.06° ± 7.3°) compared with the control group (22.32° ± 7.0°). No significant difference of the neck tilt, thoracic inlet angle, and C2–C7 angle was seen between the DSC group and the control group. Therefore, the T1 slope of the DSC group was significantly greater than that of the control group (P < 0.005). Conclusion. The DCS group was characterized by a greater T1 slope than the control group; therefore, we suggest that a high T1 slope may be a predisposing factor in developing DCS. Level of Evidence: 3

The clinical features and surgical outcomes of patients with intramedullary spinal cord cavernous malformations

BackgroundCavernous malformations (CMs) are not uncommon, but most of them are found to be located intracranially. Intramedullary CMs are rare, accounting for only 3–5% of identified total central nervous system lesions. The natural history of intramedullary CMs and their clinical features, including the risk of hemorrhage from a large series, still remains unclear and needs to be elucidated. We review our experience with surgically treated patients with intramedullary CMs and discuss the clinical features and surgical outcomes.MethodsBetween March 2004 and March 2010, a total of 21 patients with intramedullary spinal cord CMs were surgically treated in a single institution. Data from 21 patients were retrospectively analyzed.ResultsThere were 13 females and 8 males ranging in age from 10 to 70xa0years (mean age 39.3xa0years). All patients harbored single symptomatic CM of the nervous system, and multiple lesions were not found. The annual retrospective hemorrhage rate was 2.18% per patient/year. All but one CM were completely resected, and the average follow-up period was 22.1xa0months (1–73xa0months). Ten of the 21 patients experienced an improvement in neurological state, 9 patients remained unchanged, and 2 patients experienced worsening of their conditions.ConclusionsSymptomatic intramedullary CMs should be surgically removed to avoid further neurological deterioration. Though there are some limitations due to the retrospective nature of this study and its small number of patients, the prognosis was found to be related to the preoperative neurological state and to the type of symptom presentation.

Robotic resection of huge presacral tumors: Case series and comparison with an open resection

Study Design: Clinical case series and analysis. Objective: The purpose of the present study is to evaluate the advantages and disadvantages of robotic presacral tumor resection compared with conventional open approach. Summary of Background Data: Conventional open approach for huge presacral tumors in the retroperitoneal space often demands excessive hospitalization and poor cosmesis. Furthermore, narrow surgical field sometimes interrupt delicate procedures. Methods: Nine patients with huge (diameter >10 cm) presacral tumors underwent surgery. Five patients among them had robotic procedure and the others had open transperitoneal tumor resection. Operation time, blood loss, hospitalization, and complications were analyzed. Results: Robotic presacral tumor resection showed shorter operation time, less bleeding, and shorter hospitalization. Moreover, there was no complication related to abdominal adhesion. Conclusions: Although robotic resection for presacral tumor still has limitations technically and economically, robotic resection for huge presacral tumors demonstrated advantages over open resection specifically for benign neurogenic tumors.

Impact of Movement Disorders on Management of Spinal Deformity in the Elderly.

Spinal deformities are frequent and disabling complications of movement disorders such as Parkinson disease and multiple system atrophy. The most distinct spinal deformities include camptocormia, antecollis, Pisa syndrome, and scoliosis. Spinal surgery has become lower risk and more efficacious for complex spinal deformities, and thus more appealing to patients, particularly those for whom conservative treatment is inappropriate or ineffective. Recent innovations and advances in spinal surgery have revolutionized the management of spinal deformities in elderly patients. However, spinal deformity surgeries in patients with Parkinson disease remain challenging. High rates of mechanical complications can necessitate revision surgery. The success of spinal surgery in patients with Parkinson disease depends on an interdisciplinary approach, including both surgeons and movement disorder specialists, to select appropriate surgical patients and manage postoperative movement in order to decrease mechanical failures. Achieving appropriate correction of sagittal alignment with strong biomechanical instrumentation and bone fusion is the key determinant of satisfactory results.Spinal deformities are frequent and disabling complications of movement disorders such as Parkinson disease and multiple system atrophy. The most distinct spinal deformities include camptocormia, antecollis, Pisa syndrome, and scoliosis. Spinal surgery has become lower risk and more efficacious for complex spinal deformities, and thus more appealing to patients, particularly those for whom conservative treatment is inappropriate or ineffective. Recent innovations and advances in spinal surgery have revolutionized the management of spinal deformities in elderly patients. However, spinal deformity surgeries in patients with Parkinson disease remain challenging. High rates of mechanical complications can necessitate revision surgery. The success of spinal surgery in patients with Parkinson disease depends on an interdisciplinary approach, including both surgeons and movement disorder specialists, to select appropriate surgical patients and manage postoperative movement in order to decrease mechanical failures. Achieving appropriate correction of sagittal alignment with strong biomechanical instrumentation and bone fusion is the key determinant of satisfactory results.