Development of Neuromonitoring Pedicle Screw - Results of Electrical Resistance and Neurophysiologic Test in Pig Model.

OBJECTIVE: To analyze the electrical resistance of a newly developed neuromonitoring pedicle screw (Neuro-PS) and to verify the electrophysiologic properties of the Neuro-PS in a pig model. METHODS: We developed 2 types of the Neuro-PS in which a gold lead was located internally (type I) and externally (type II). We measured the electrical resistance of the Neuro-PS and the conventional screw and analyzed the electrical thresholds of triggered EMG (t-EMG) of each screw by intentionally penetrating the medial pedicle wall and contacting the exiting nerve root in a pig model. RESULTS: The electrical resistances of the Neuro-PS were remarkably lower than that of the conventional screw. In electrophysiologic testing, only the type II Neuro-PS under the leadnerve contact condition showed a significantly lower stimulation threshold as compared to the conventional screw. CONCLUSION: The Neuro-PS demonstrated lower electrical resistances than the conventional screw. The type II Neuro-PS under the lead-nerve contact condition showed a significantly lower stimulation threshold compared to that of the other screws in the t-EMG test.

Correction of marked sagittal deformity with circumferential minimally invasive surgery using oblique lateral interbody fusion in adult spinal deformity.

BACKGROUND: Spinal surgery performed entirely with minimally invasive surgery is referred to as circumferential MIS (cMIS). However, cMIS still has a limited sagittal correction capability for adult spinal deformity (ASD) with a marked sagittal deformity. We investigated the effectiveness of cMIS using oblique lateral interbody fusion (OLIF) and percutaneous posterior spine fixation in correcting marked sagittal deformity. METHODS: This study retrospectively evaluated 23 patients with ASD with marked sagittal deformity who underwent cMIS using OLIF without osteotomy and were followed-up for at least 24 months (whole group). The whole group was divided into the following two groups according to the type of interbody fusion at L5-S1: the OLIF51 group (n = 13) underwent OLIF at L1-L5 and L5-S1 and the TLIF51 group (n = 10) underwent OLIF at L1-L5 and transforaminal lumbar interbody fusion (TLIF) at L5-S1. RESULTS: Sagittal vertebral axis (SVA; 125.7 vs. 29.5 mm, p < 0.001), lumbar lordosis (LL; 18.2° vs. 51.7°, p < 0.001), and pelvic incidence-LL mismatch (PI-LL, 35.5° vs. 5.3°) significantly improved postoperatively in the whole group. The OLIF51 group showed significantly higher postoperative LL than the TLIF51 group (55.5° vs. 46.9°, p < 0.001). OLIF yielded a significantly greater disc angle at L5-S1 than did TLIF (18.4° vs. 6.9°, p < 0.001). Proximal junctional kyphosis occurred significantly earlier in the OLIF51 group than in the TLIF51 group (8.6 vs. 26.3 months, p < 0.001). CONCLUSION: Successful sagittal correction in ASD patients with marked sagittal deformity was achieved with cMIS using OLIF. OLIF at L5-S1 showed a synergistic effect in sagittal deformity correction by cMIS.

Risk Factors for Symptomatic Contralateral Foraminal Stenosis After Unilateral Transforaminal Lumbar Interbody Fusion.

OBJECTIVE: The most common cause of contralateral symptoms after unilateral transforaminal lumbar interbody fusion (TLIF) is contralateral foraminal stenosis (FS). This retrospective cohort study aimed to investigate the cause of and risk factors for contralateral FS after unilateral TLIF with a single cage. METHODS: Patients with degenerative lumbar spinal disorders who underwent unilateral TLIF at L4-5 were divided into 2 groups: those without contralateral radicular symptoms after surgery (group A; n = 340) and those with contralateral radicular symptoms after surgery (group B; n = 16). We investigated the influence of various radiological and cage-related factors on postoperative contralateral FS with radicular symptoms. The cage location indicates whether the cage's anterior tip crosses the disc midline-exceeding 50%-and in such a case, how far. RESULTS: Group B showed significantly increased postoperative coronal angle and sagittal angle and decreased contralateral foraminal height and foraminal area. Statistically significant (P < 0.01) factors according to the multivariate logistic regression analysis were the preoperative sagittal range of motion (odds ratio [OR]: 1.562, P = 0.004) and cage location (OR: 2.047, P = 0.015). The cutoff values for the sagittal range of motion and the cage location were 9.0° and 50.5%, respectively. The preoperative and postoperative 6-month visual analog scale scores and Oswestry disability index values were not significantly different between the groups. CONCLUSIONS: The 2 most meaningful risk factors were the preoperative sagittal range of motion and cage location. Inserting the cage beyond the disc midline, especially in patients with a high preoperative sagittal range of motion (≥9.0°), would help reduce postoperative complications.

Usefulness of Oblique Lateral Interbody Fusion at L5-S1 Level Compared to Transforaminal Lumbar Interbody Fusion.

OBJECTIVE: The use of oblique lateral interbody fusion at the L5-S1 level (OLIF51) is increasing, but no study has directly compared OLIF51 and transforaminal lumbar interbody fusion (TLIF) at the L5-S1 level. We evaluated the usefulness of OLIF51 by comparing clinical and radiologic outcomes with those of TLIF at the same L5-S1 level. METHODS: We retrospectively reviewed and compared 74 patients who underwent OLIF51 (OLIF51 group) and 74 who underwent TLIF at the L5-S1 level (TLIF51 group). Clinical outcomes were assessed with the visual analogue scale for back pain and leg pain and the Oswestry Disability Index. Mean disc height (MDH), foraminal height (FH), disc angle (DA), fusion rate, and subsidence rate were measured for radiologic outcomes. RESULTS: The OLIF51 group used significantly higher, wider, and larger-angled cages than the TLIF51 group (p<0.001). The postoperative MDH and FH were significantly greater in the OLIF51 group than in the TLIF51 group (p<0.001). The postoperative DA was significantly larger in the OLIF51 group than in the TLIF51 group by more than 10º (p<0.001). The fusion rate was 81.1% and 87.8% at postoperative 6 months in the OLIF51 and TLIF51 groups, respectively, and the TLIF51 group showed a higher fusion rate (p<0.05). The subsidence rate was 16.2% and 25.3% in the OLIF51 and TLIF51 groups, respectively, and the OLIF51 group showed a lower subsidence rate (p<0.05). CONCLUSION: OLIF51 was more effective for the indirect decompression of foraminal stenosis, providing strong mechanical support with a larger cage, and making a greater lordotic angle with a high-angle cage than with TLIF.

Correction of Spondylolisthesis by Lateral Lumbar Interbody Fusion Compared with Transforaminal Lumbar Interbody Fusion at L4-5.

OBJECTIVE: In an aging society, the number of patients with symptomatic degenerative spondylolisthesis (DS) is increasing and there is an emerging need for fusion surgery. However, few studies have compared transforaminal lumbar interbody fusion (TLIF) and lateral lumbar interbody fusion (LLIF) for the treatment of patients with DS. The purpose of this study was to investigate the clinical and radiological outcomes between TLIF and LLIF in DS. METHODS: We enrolled patients with symptomatic DS at L4-5 who underwent TLIF with open pedicle screw fixation (TLIF group, n=41) or minimally invasive LLIF with percutaneous pedicle screw fixation (LLIF group, n=39) and were followed-up for more than one year. Clinical (visual analog scale and Oswestry disability index) and radiological outcomes (spondylolisthesis rate, segmental sagittal angle [SSA], mean disc height [MDH], intervertebral foramen height [FH], cage subsidence, and fusion rate) were assessed. And we assessed the changes in radiological parameters between the postoperative and the last follow-up periods. RESULTS: Preoperative radiological parameters were not significantly different between the two groups. LLIF was significantly superior to TLIF in immediate postoperative radiological results, including reduction of spondylolisthesis rate (3.8% and 7.2%), increase in MDH (13.9 mm and 10.3 mm) and FH (21.9 mm and 19.4 mm), and correction of SSA (18.9° and 15.6°) (p<0.01), and the changes were more stable from the postoperative period to the last follow-up (p<0.01). Cage subsidence was observed significantly less in LLIF (n=6) than TLIF (n=21). Fusion rate was not different between the two groups. The clinical outcomes did not differ significantly at any time point between the two groups. Complications were not statistically significant. However, TLIF showed chronic mechanical problems with screw loosening in four patients and LLIF showed temporary symptoms associated with the surgical approach, such as psoas and ileus muscle symptoms in three and two cases, respectively. CONCLUSION: LLIF was more effective than TLIF for spondylolisthesis reduction, likely due to the higher profile cage and ligamentotactic effect. In addition, LLIF showed mechanical stability of the reduction level by using a cage with a larger footprint. Therefore, LLIF should be considered a surgical option before TLIF for patients with unstable DS.

Effect of Cage in Radiological Differences between Direct and Oblique Lateral Interbody Fusion Techniques.

OBJECTIVE: Few studies have reported direct comparative data of lumbar spine angles between direct lateral interbody fusion (DLIF) and oblique lateral interbody fusion (OLIF). The purpose of this study was to investigate the clinical and radiological outcomes of DLIF and OLIF, and determine influential factors. METHODS: The same surgeon performed DLIF from May 2011 to August 2014 (n=201) and OLIF from September 2014 to September 2016 (n=142). Radiological parameters, cage height, cage angle (CA), cage width (CW), and cage location were assessed. We checked the cage location as the distance (mm) from the anterior margin of the disc space to the anterior metallic indicator of the cage in lateral images. RESULTS: There were significant differences in intervertebral foramen height (FH; 22.0±2.4 vs. 21.0±2.1 mm, p<0.001) and sagittal disc angle (SDA; 8.7±3.3 vs. 11.3±3.2˚, p<0.001) between the DLIF and OLIF groups at 7 days postoperatively. CA (9.6±3.0 vs. 8.1±2.9˚, p<0.001) and CW (21.2±1.6 vs. 19.2±1.9 mm, p<0.001) were significantly larger in the OLIF group compared to the DLIF group. The cage location of the OLIF group was significantly more anterior than the DLIF group (6.7±3.0 vs. 9.1±3.6 mm, p<0.001). Cage subsidence at 1 year postoperatively was significantly worse in the DLIF group compared to the OLIF group (1.0±1.5 vs. 0.4±1.1 mm, p=0.001). Cage location was significantly correlated with postoperative FH (ß=0.273, p<0.001) and postoperative SDA (ß=-0.358, p<0.001). CA was significantly correlated with postoperative FH (ß=-0.139, p=0.044) and postoperative SDA (ß=0.236, p=0.001). Cage location (ß=0.293, p<0.001) and CW (ß=-0.225, p<0.001) were significantly correlated with cage subsidence. CONCLUSION: The cage location, CA, and CW seem to be important factors which result in the different-radiological outcomes between DLIF and OLIF.

The Effect of Postoperative Use of Teriparatide Reducing Screw Loosening in Osteoporotic Patients.

OBJECTIVE: The loosening of pedicle screws (PS) is one of the frequent problems of spinal surgery in the patients with osteoporosis. Previous studies had revealed that intermittent injection of teriparatide could reduce PS loosening by improving bone mass and quality when their patients took parathyroid hormone for a considerable duration before surgery. However, although the teriparatide is usually used after spine surgery in most clinical situations, there was no report on the efficacy of teriparatide treatment started after spine surgery. The purpose of this retrospective study was to examine the efficacy of teriparatide treatment started immediately after lumbar spinal surgery to prevent pedicle screw loosening in patients with osteoporosis. METHODS: We included 84 patients with osteoporosis and degenerative lumbar disease who underwent transforaminal interbody fusion and PS fixation and received parathyroid hormone or bisphosphonate (BP) postoperatively. They were divided into teriparatide group (daily injection of 20 µg of teriparatide for 6 months, 33 patients, 172 screws) and BP group (weekly oral administration of 35 mg of risedronate, 51 patients, 262 screws). Both groups received calcium (500 mg/day) and cholecalciferol (1000 IU/day) together. The screw loosening was evaluated with simple radiographic exams at 6 and 12 months after the surgery. We counted the number of patients with PS loosening and the number of loosened PS, and compared them between the two groups. Clinical outcomes were evaluated using visual analog scale (VAS) and Oswestry disability index (ODI) preoperatively, and at 12 months after surgery. RESULTS: There was no significant difference in the age, sex, diabetes, smoking, bone mineral density, body mass index, and the number of fusion levels between the two groups. The number of PS loosening within 6 months after surgery did not show a significant difference between the teriparatide group (6.9%, 12/172) and the BP group (6.8%, 18/272). However, during 6-12 months after surgery, it was significantly lower in the teriparatide group (2.3%, 4/172) than the BP group (9.2%, 24/272) (p<0.05). There was no significant difference in the number of patients showing PS loosening between the teriparatide and BP groups. The teriparatide group showed a significantly higher degree of improvement of the bone mineral density (T-score) than that of BP group (p<0.05). There was no significant difference in the pre- and post-operative VAS and ODI between the groups. CONCLUSION: Our data suggest that the teriparatide treatment starting immediately after lumbar spinal fusion surgery could reduce PS loosening compared to BP.

Preservation of Motion at the Surgical Level after Minimally Invasive Posterior Cervical Foraminotomy.

OBJECTIVE: Although minimally invasive posterior cervical foraminotomy (MI-PCF) is an established approach for motion preservation, the outcomes are variable among patients. The objective of this study was to identify significant factors that influence motion preservation after MI-PCF. METHODS: Forty-eight patients who had undergone MI-PCF between 2004 and 2012 on a total of 70 levels were studied. Cervical parameters measured using plain radiography included C2-7 plumb line, C2-7 Cobb angle, T1 slope, thoracic outlet angle, neck tilt, and disc height before and 24 months after surgery. The ratios of the remaining facet joints after MI-PCF were calculated postoperatively using computed tomography. Changes in the distance between interspinous processes (DISP) and the segmental angle (SA) before and after surgery were also measured. We determined successful motion preservation with changes in DISP of ≤3 mm and in SA of ≤2°. RESULTS: The differences in preoperative and postoperative DISP and SA after MI-PCF were 0.03±3.95 mm and 0.34±4.46°, respectively, fulfilling the criteria for successful motion preservation. However, the appropriate level of motion preservation is achieved in cases in which changes in preoperative and postoperative DISP and SA motions are 55.7 and 57.1%, respectively. Based on preoperative and postoperative DISP, patients were divided into three groups, and the characteristics of each group were compared. Among these, the only statistically significant factor in motion preservation was preoperative disc height (Pearson's correlation coefficient=0.658, p<0.001). The optimal disc height for motion preservation in regard to DISP ranges from 4.18 to 7.08 mm. CONCLUSION: MI-PCF is a widely accepted approach for motion preservation, although desirable radiographic outcomes were only achieved in approximately half of the patients who had undergone the procedure. Since disc height appears to be a significant factor in motion preservation, surgeons should consider disc height before performing MI-PCF.

What Effects Does Necrotic Area of Contrast-Enhanced MRI in Osteoporotic Vertebral Fracture Have on Further Compression and Clinical Outcome?

OBJECTIVE: The objective of this study was to analyze the correlation between further compression and necrotic area in osteoporotic vertebral fracture (OVF) patients with contrast-enhanced magnetic resonance imaging (CEMRI). In addition, we investigated the radiological and clinical outcome according to the range of the necrotic area. METHODS: Between 2012 and 2014, the study subjects were 82 OVF patients who did not undergo vertebroplasty or surgical treatment. The fracture areas examined on CEMRI at admission were defined as edematous if enhancement was seen and as necrotic if no enhancement was seen. The correlation between further compression and the necrotic and edematous areas of CEMRI, age, and bone mineral density was examined. Also, necrotic areas were classified into those with less than 25% (non-necrosis group) and those with more than 25% (necrosis group) according to the percentages of the entire vertebral body. For both groups, further compression and the changes in wedge and kyphotic angles were examined at admission and at 1 week, 3 months, and 6 months after admission, while the clinical outcomes were compared using the visual analog scale (VAS) and Eastern Cooperative Oncology Group (ECOG) performance status grade. RESULTS: Further compression was 14.78±11.11% at 1 month and 21.75±14.43% at 6 months. There was a very strong correlation between the necrotic lesion of CEMRI and further compression (r=0.690, p<0.001). The compression of the necrosis group was 33.52±12.96%, which was higher than that of the non-necrosis group, 14.96±10.34% (p<0.005). Also, there was a statistically significantly higher number of intervertebral cleft development and surgical treatments being performed in the necrosis group than in the non-necrosis group (p<0.005). Moreover, there was a statistical difference in the decrease in the height of the vertebral body, and an increase was observed in the kyphotic change of wedge angle progression. There was also a difference in the VAS and ECOG performance scales. CONCLUSION: The necrotic area of CEMRI in OVF had a strong correlation with further compression over time. In addition, with increasing necrosis, intervertebral clefts occurred more frequently, which induced kyphotic changes and resulted in poor clinical outcomes. Therefore, identifying necrotic areas by performing CEMRI on OVF patients would be helpful in determining their prognosis and treatment course.

Comparative Analysis between Total Disc Replacement and Posterior Foraminotomy for Posterolateral Soft Disc Herniation with Unilateral Radiculopathy : Clinical and Biomechanical Results of a Minimum 5 Years Follow-up.

OBJECTIVE: To compare the clinical outcomes and biomechanical effects of total disc replacement (TDR) and posterior cervical foraminotomy (PCF) and to propose relative inclusion criteria. METHODS: Thirty-five patients who underwent surgery between 2006 and 2008 were included. All patients had single-level disease and only radiculopathy. The overall sagittal balance and angle and height of a functional segmental unit (FSU; upper and lower vertebral body of the operative lesion) were assessed by preoperative and follow-up radiographs. C2-7 range of motion (ROM), FSU, and the adjacent segment were also checked. RESULTS: The clinical outcome of TDR (group A) was tended to be superior to that of PCF (group B) without statistical significance. In the group A, preoperative and postoperative upper adjacent segment level motion values were 8.6±2.3 and 8.4±2.0, and lower level motion values were 8.4±2.2 and 8.3±1.9. Preoperative and postoperative FSU heights were 37.0±2.1 and 37.1±1.8. In the group B, upper level adjacent segment motion values were 8.1±2.6 and 8.2±2.8, and lower level motion values were 6.5±3.3 and 6.3±3.1. FSU heights were 37.1±2.0 and 36.2±1.8. The postoperative FSU motion and height changes were significant (p<0.05). The patient's satisfaction rates for surgery were 88.2% in group A and 88.8% in group B. CONCLUSION: TDR and PCF have favorable outcomes in patients with unilateral soft disc herniation. However, patients have different biomechanical backgrounds, so the patient's biomechanical characteristics and economic status should be understood and treated using the optimal procedure.

The fatty degeneration of lumbar paraspinal muscles on computed tomography scan according to age and disc level.

BACKGROUND CONTEXT: Spinal degeneration can occur not only in the bone and disc but also in muscles. Fatty infiltration (FI) and decreased volume have been described as characteristic changes that occur in muscle degeneration. Many studies about the lumbar paraspinal muscles have been conducted on patients with spine problems. However, the natural changes of age-dependent degeneration in the paraspinal muscles have not been studied properly. PURPOSE: The purpose of this study is to investigate age- and level-dependent changes of the lumbar paraspinal muscles in the population without lumbar spinal symptoms. STUDY DESIGN: This study is a retrospective case-control study. PATIENT SAMPLE: A total of 887 patients who underwent computed tomography scan for abdomen and pelvis (APCT) between January 2013 and December 2013 were enrolled. After excluding 237 patients with medical history of spine surgery, low back pain, myopathy, muscular dystrophy, infectious disease, vertebral fracture, and deformity, 650 patients were finally subjected to this study. OUTCOME MEASURE: The patients were divided into three age groups: young (20-39 years old), middle (40-59 years old), and old (60-89 years old). The degree of FI was checked twice for multifidus muscle (MF), erector spinae muscle (ES), and psoas muscle (PS) at each disc level from L1 to S1 on APCT by two investigators. The FI was measured as the Hounsfield unit, a mean density (MD) on CT. METHODS: The age differences were compared with the data of the young group, and the level differences were compared with the data of the L1-L2 level. Student t test and intraclass correlation coefficient were checked for statistical analysis. RESULTS: The gender ratio was not significantly different among the groups. Comparing with the young group, the MD of MF significantly decreased at L5-S1 in the middle group (p<.05), and at L3-L4-L5-S1 in the old group (p<.05). The MD of ES was significantly decreased at all levels in the old group (p<.05) but not significant in the middle group. Comparing with the L1-L2 level, the MD of MF significantly decreased at L5-S1 in the middle group (p<.05) and at L4-L5-S1 in the old group (p<.05). The MD of ES was significantly decreased at L5-S1 in the young and middle groups (p<.05) and at L4-L5-S1 in the old group (p<.01) compared with those at L1-L2. According to the age- and level-dependent changes of MD in the MF and ES, there was a tendency of progressive increase of FI in the muscles with age, which seemed to start from L5-S1 and spread to the upper levels. The age-dependent fatty degeneration appeared wider in the ES than the MF. The level-dependent FI of the ES showed a similar pattern with the MF, but the change of the ES seemed to start earlier in age than the MF at the L5-S1. There was no significant MD change in the PS according to age and level. Intraobserver and interobserver reliabilities were both high across all of the muscles (0.86-0.94 and 0.83-0.92). CONCLUSIONS: As a result, the degree of intramuscular fat infiltration seems to be affected by age, disc level, and muscle type. It seems to be more prominent in the extensor muscles, extending from lower to upper levels.

Chronic Paraspinal Muscle Injury Model in Rat.

OBJECTIVE: The objective of this study is to establish an animal model of chronic paraspinal muscle injury in rat. METHODS: Fifty four Sprague-Dawley male rats were divided into experimental group (n=30), sham (n=15), and normal group (n=9). Incision was done from T7 to L2 and paraspinal muscles were detached from spine and tied at each level. The paraspinal muscles were exposed and untied at 2 weeks after surgery. Sham operation was done by paraspinal muscles dissection at the same levels and wound closure was done without tying. Kyphotic index and thoracolumbar Cobb's angle were measured at preoperative, 2, 4, 8, and 12 weeks after the first surgery for all groups. The rats were sacrificed at 4, 8, and 12 weeks after the first surgery, and performed histological examinations. RESULTS: At 4 weeks after surgery, the kyphotic index decreased, but, Cobb's angle increased significantly in the experimental group (p<0.05), and then that were maintained until the end of the experiment. However, there were no significant differences of the kyphotic index and Cobb's angle between sham and normal groups. In histological examinations, necrosis and fibrosis were observed definitely and persisted until 12 weeks after surgery. There were also presences of regenerated muscle cells which nucleus is at the center of cytoplasm, centronucleated myofibers. CONCLUSION: Our chronic injury model of paraspinal muscles in rats shows necrosis and fibrosis in the muscles for 12 weeks after surgery, which might be useful to study the pathophysiology of the degenerative thoracolumbar kyphosis or degeneration of paraspinal muscles.

Cervical Myelopathy Caused by Intracranial Dural Arteriovenous Fistula.

Intracranial dural arteriovenous fistula (dAVF) usually results in various problems in the brain. But it can be presented as a myelopathy, which may make early diagnosis and management to be difficult. We recently experienced a case of cervical myelopathy caused by intracranial dAVF. A 60-year-old man presented with a 3-year history of gait disturbance due to a progressive weakness of both legs. Neurological examination revealed spastic paraparesis (grade IV) and Babinski sign on both sides. Magnetic resonance imaging showed serpentine vascular signal voids at C2-T1 on T2-weighted image with increased signal intensity and swelling of spinal cord at C1-C4. We performed a brain computed tomography angiography and found intracranial dAVF with multiple arteriovenous shunts. Venous drainages were noted at tentorial veins and cervical perimedullary veins. After Onyx embolization, the patient showed gradual improvement in motor power and gait disturbance. The venous drainage pattern is a well-known prognostic factor of dAVF. In our case, the intracranial dAVF drained to spinal perimedullary vein, which seemed to result in the ischemic myelopathy. Although it is rare condition, it sometimes can cause serious complications. Therefore, we should keep in mind the possibility of intracranial dAVF when a patient presents myelopathy.

The Prevalence of Undiagnosed Presurgical Cognitive Impairment and Its Postsurgical Clinical Impact in Older Patients Undergoing Lumbar Spine Surgery.

OBJECTIVE: Because elderly patients are undergoing more surgeries, the importance of postoperative cognitive impairment (CI) evaluations is rising, especially for spine surgery, which is related to subjective pain. We investigated the prevalence of undiagnosed CI among elderly patients who underwent spine surgery and the impact of CI on postoperative outcomes. METHODS: The preoperative cognitive statuses of 129 patients over 65 who underwent lumbar spine surgery from 2012 to 2014 were determined with the Mini-Mental State Examination, and patients with scores under 24 were diagnosed with CI. The patients were then divided into a CI group (n=49) and non-cognitive impairment (NCI) group (n=80). RESULTS: Among the 129 patients, 49 (38.0%) were diagnosed with CI, and 9 (7.0%) had severe CI. The age of the CI group (72.88±6.20 years) was significantly greater than that of the NCI group (69.96±4.53 years). In contrast, the postoperative visual analog scale scores and performance statuses did not differ significantly. However, postoperative delirium was more frequent and the hospital stay length was longer in the CI group compared with the NCI group (p<0.05). CONCLUSION: A high prevalence of undiagnosed CI was discovered among elderly patients undergoing spine surgery. The existence of CI was associated with higher rates of postoperative delirium and prolonged hospital stays, which affected clinical outcomes. Thus, CI assessments should be included in preoperative evaluations of elderly patients prior to spine surgery.

Spinous Process-Splitting Hemilaminoplasty for Intradural and Extradural Lesions.

OBJECTIVE: To describe a novel spinous process-splitting hemilaminoplasty technique for the surgical treatment of intradural and posterior epidural lesions that promotes physiological restoration. METHODS: The spinous process was split, the area of the facet lamina junction was drilled, and en bloc hemilaminectomy was then performed. After removing intradural and posterior epidural lesions, we fitted the previously en bloc-removed bone to the pre-surgery same shape, and held it in place with non-absorbable sutures. Surgery was performed on 16 laminas from a total of nine patients between 2011 and 2014. Bony union of the reconstructed lamina was assessed using computed tomography (CT) at 6 months after surgery. RESULTS: Spinous process-slitting hemilaminoplasty was performed for intradural extramedullary tumors in eight patients and for ossification of the ligament flavum in one patient. Because we were able to visualize the margin of the ipsilateral and contralateral dura, we were able to secure space for removal of the lesion and closure of the dura. None of the cases showed spinal deformity or other complications. Bone fusion and maintenance of the spinal canal were found to be perfect on CT scans. CONCLUSION: The spinous process-splitting hemilaminoplasty technique presented here was successful in creating sufficient space to remove intradural and posterior epidural lesions and to close the dura. Furthermore, we were able to maintain the physiological barrier and integrity after surgery because the posterior musculature and bone structures were restored.

Acute Contralateral Radiculopathy after Unilateral Transforaminal Lumbar Interbody Fusion.

OBJECTIVE: Cases of contralateral radiculopathy after a transforaminal lumbar interbody fusion with a single cage (unilateral TLIF) had been reported, but the phenomenon has not been explained satisfactorily. The purpose of this study was to determine its incidence, causes, and risk factors. METHODS: We did retrospective study with 546 patients who underwent a unilateral TLIF, and used CT and MRI to study the causes of contralateral radicular symptoms that appeared within a week postoperatively. Clinical and radiological results were compared by dividing the patients into the symptomatic group and asymptomatic group. RESULTS: Contralateral symptoms occurred in 32 (5.9%) of the patients underwent unilateral TLIF. The most common cause of contralateral symptoms was a contralateral foraminal stenosis in 22 (68.8%), screw malposition in 4 (12.5%), newly developed herniated nucleus pulposus in 3 (9.3%), hematoma in 1 (3.1%), and unknown origin in 2 patients (6.3%). 16 (50.0%) of the 32 patients received revision surgery. There was no difference in visual analogue scale and Oswestry disability index between the two groups at discharge. Both preoperative and postoperative contralateral foraminal areas were significantly smaller, and postoperative segmental angle was significantly greater in the symptomatic group comparing to those of the asymptomatic group (p<0.05). CONCLUSION: The incidence rate is not likely to be small (5.9%). If unilateral TLIF is performed for cases when preoperative contralateral foraminal stenosis already exists or when a large restoration of segmental lordosis is required, the probability of developing contralateral radiculopathy is increased and caution from the surgeon is needed.

The Effects of Spinopelvic Parameters and Paraspinal Muscle Degeneration on S1 Screw Loosening.

OBJECTIVE: To investigate risk factors for S1 screw loosening after lumbosacral fusion, including spinopelvic parameters and paraspinal muscles. METHODS: We studied with 156 patients with degenerative lumbar disease who underwent lumbosacral interbody fusion and pedicle screw fixation including the level of L5-S1 between 2005 and 2012. The patients were divided into loosening and non-loosening groups. Screw loosening was defined as a halo sign larger than 1 mm around a screw. We checked cross sectional area of paraspinal muscles, mean signal intensity of the muscles on T2 weight MRI as a degree of fatty degeneration, spinopelvic parameters, bone mineral density, number of fusion level, and the characteristic of S1 screw. RESULTS: Twenty seven patients showed S1 screw loosening, which is 24.4% of total. The mean duration for S1 screw loosening was 7.3±4.1 months after surgery. Statistically significant risk factors were increased age, poor BMD, 3 or more fusion levels (p<0.05). Among spinopelvic parameters, a high pelvic incidence (p<0.01), a greater difference between pelvic incidence and lumbar lordotic angle preoperatively (p<0.01) and postoperatively (p<0.05). Smaller cross-sectional area and high T2 signal intensity in both multifidus and erector spinae muscles were also significant muscular risk factors (p<0.05). Small converging angle (p<0.001) and short intraosseous length (p<0.05) of S1 screw were significant screw related risk factors (p<0.05). CONCLUSION: In addition to well known risk factors, spinopelvic parameters and the degeneration of paraspinal muscles also showed significant effects on the S1 screw loosening.

An Intramuscular Hemangioma at the Cervical Muscle: A Case Report.

Intramuscular hemangioma (IMH) primarily develops in the skeletal muscles of the limbs or trunk. The occurrence of IMH in the neck muscle is very rare. In the present report, we describe a case of IMH in the posterior neck muscle. A 58-year-old woman presented with a mass on the right posterior neck area, which had developed 2 years previously. The tumor was round in shape, had a size of 3.5×3.0 cm, and was fixed to the surrounding soft tissue. The patient complained of mild dull pain and tenderness at the mass without reddish discoloration. The mass showed a diurnal variation in size - the mass grew in size in the morning and became smaller in the afternoon. Preoperative study confirmed the vascular nature of the tumor. During peritumoral dissection, the mass shrank rapidly following profuse bleeding and arterial cauterization, and hence, it was difficult to distinguish the mass from the surrounding tissues. A total resection was possible with careful dissection of its fibrotic boundary. Based on the histological findings, a definitive diagnosis of cavernous type IMH was made. An initial suspicion of IMH, according to the clinical findings, would be helpful for decision making of further evaluations and surgical plan.

Two Cases of Klippel-Feil Syndrome with Cervical Myelopathy Successfully Treated by Simple Decompression without Fixation.

Klippel-Feil syndrome (KFS) is a congenital developmental disorder of cervical spine, showing short neck with restricted neck motion, low hairline, and high thoracic cage due to multilevel cervical fusion. Radiculopathy or myelopathy can be accompanied. There were 2 patients who were diagnosed as KFS with exhibited radiological and physical characteristics. Both patients had stenosis and cord compression at C1 level due to anterior displacement of C1 posterior arch secondary to kyphotic deformity of upper cervical spine, which has been usually indicative to craniocervical fixation. One patient was referred due to quadriparesis detected after surgery for aortic arch aneurysmal dilatation. The other patient was referred to us due to paraparesis and radiating pain in all extremities developed during gynecological examinations. Decompressive C1 laminectomy was done for one patient and additional suboccipital craniectomy for the other. No craniocervical fixation was done because there was no spinal instability. Motor power improved immediately after the operation in both patients. Motor functions and spinal stability were well preserved in both patients for 2 years. In KFS patients with myelopathy at the C1 level without C1-2 instability, a favorable outcome could be achieved by a simple decompression without spinal fixation.

Does a zero-profile anchored cage offer additional stabilization as anterior cervical plate?

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: This study aimed to compare 3 different surgical methods of single-level anterior cervical interbody fusion consisting of stand-alone cages (SCs), cages with plates (CPs), and anchored cages (ACs) (zero-profile). It focused on postoperative retention and motion stabilization. SUMMARY OF BACKGROUND DATA: Several authors reported the radiological and clinical results of ACs, which seem similar to plates. However, it remains unclear whether ACs offer additional stabilization like plates. METHODS: Between 2005 and 2011, SCs (n=60) and CPs (n=18) were used to surgically treat patients with single-level cervical degenerative diseases. From January 2012 to June 2013, ACs were used (n=23). We compared retention (cervical alignment, segmental angle, and segmental height) and motion stabilization (change of segmental angle and distance of interspinous process in flexion/extension). We also investigated subsidence, fusion rates, and clinical outcomes. The mean follow-up period was 19.9 months. RESULTS: The CP and AC groups showed significantly more retention at 12 months after surgery than the SC group (P<0.05). The CP group had significantly greater motion stabilization than the SC group (P<0.05). However, there was no statistically significant difference between the AC and SC groups. The subsidence rates of the SC, AC, and CP groups were 40.0%, 21.7%, and 11.1%, whereas the fusion rates were 83.3%, 87.0%, and 100.0%, respectively. Arm and neck visual analogue scale scores and Odom criteria showed superior results in the CP and AC groups than in the SC group (P<0.05). CONCLUSION: The AC displayed similar retention and clinical outcomes to those of the CP. However, the AC was inferior to the CP in motion stabilization, subsidence prevention, and fusion rate. Therefore, for patients who require strong postoperative motion stabilization, CPs rather than ACs should be used. LEVEL OF EVIDENCE: 4.