scholarly journals Variation in the position of the conus medullaris and dural sac in adult dogs

2019 ◽  
Vol 185 (1) ◽  
pp. 20-20 ◽  
Author(s):  
Zohra Khan ◽  
Elizabeth Munro ◽  
Darren Shaw ◽  
Kiterie ME Faller
Keyword(s):  
Spinal Cord ◽  
Regression Analysis ◽  
Significant Relationship ◽  
Conus Medullaris ◽  
Similar Relationship ◽  
Terminal Position ◽  
Dural Sac ◽  
Termination Point ◽  
T2 Weighted Images

Although it has long been stated that the level of spinal cord termination varies depending on the size of the dog, the evidence for this remains limited. The aim of this study is to investigate the position of the conus medullaris (CM) and dural sac (DS) in a population of dogs of varying size. MRIs of the thoracolumbosacral spine of 101 dogs were included. The location of CM and DS was determined on sagittal T2-weighted images and T1-weighted images, respectively, by three independent observers. The bodyweight and the back length were used as markers of size. Regression analysis showed that the termination point of the CM had a statistically significant relationship with bodyweight (R2=0.23, P<0.05). Although not statistically significant (P=0.058), a similar relationship was found between CM and back length (R2=0.21). No statistically significant relationship was found between the termination point of the DS and bodyweight (P=0.24) or back length (P=0.19). The study confirms the terminal position of the CM is dependent on size, with a more cranial position with increasing size; however, the termination point of DS remains constant irrespective of dog size.

Surgical treatment of the retethered spinal cord after repair of lipomyelomeningocele

1991 ◽  
Vol 74 (5) ◽  
pp. 709-714 ◽  
Author(s):  
Hiroaki Sakamoto ◽  
Akira Hakuba ◽  
Ken Fujitani ◽  
Shuro Nishimura
Keyword(s):  
Spinal Cord ◽  
Dura Mater ◽  
Conus Medullaris ◽  
Posterior Arch ◽  
Pia Mater ◽  
Dense Adhesion ◽  
Content Type ◽  
Dural Sac ◽  
Long Term Observation

✓ In a series of 75 patients with surgically treated lipomyelomeningoceles, the neurological condition of six patients deteriorated 6 months to 14 years after the operation due to repeat tethering of the spinal cord. The tethering resulted from postoperative dense adhesion between the cord and the overlying dura mater. Two of the six patients underwent conventional repeat untethering procedures, and the remaining four were successfully treated with a new surgical technique developed by the authors to prevent such dural adhesion. For this procedure, after complete untethering of the spinal cord, the lumbosacral cord is retained in the center of the dural sac by fine stay sutures between the pia mater of the conus medullaris and the ventral dura mater. In addition, the dura mater is tacked to the posterior arch which is reconstructed with bone grafts at one or two bifid vertebral levels. During a postoperative follow-up period of 1 to 3 years, no further deterioration has been observed and magnetic resonance studies have demonstrated a space filled with cerebrospinal fluid (CSF) around the lumbosacral cord. The authors conclude that long-term observation, both neurological and radiological, is essential even after successful repair of a lipomyelomeningocele. This new surgical procedure can maintain a CSF bath around the lumbosacral cord, thus preventing dural adhesion. Application of this technique will hopefully be beneficial in lipomyelomeningocele patients with a high risk of cord retethering after initial repair.

scholarly journals The Level of Conus Medullaris in 629 Healthy Japanese Individuals

2021 ◽  
Vol 10 (14) ◽  
pp. 3182
Author(s):  
Hiroaki Nakashima ◽  
Keigo Ito ◽  
Yoshito Katayama ◽  
Mikito Tsushima ◽  
Kei Ando ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Magnetic Resonance ◽  
Pelvic Tilt ◽  
Pelvic Incidence ◽  
Multivariate Regression Analysis ◽  
Conus Medullaris ◽  
Magnetic Resonance Images ◽  
Factors Affecting ◽  
Adult Volunteers ◽  
Significant Factors

The conus medullaris typically terminates at the L1 level; however, variations in its level and the factors associated with the conus medullaris level are unclear. We investigated the level of conus medullaris on magnetic resonance imaging in healthy volunteers. In total, 629 healthy adult volunteers (≥50 individuals of each sex and in each decade of age from 20 to 70) were enrolled. The level of the conus medullaris was assessed based on the T2-weighted sagittal magnetic resonance images, and factors affecting its level were investigated employing multivariate regression analysis including the participants’ background and radiographical parameters. L1 was the most common conus medullaris level. Participant height was significantly shorter in the caudally placed conus medullaris (p = 0.013). With respect to the radiographical parameters, pelvic incidence (p = 0.003), and pelvic tilt (p = 0.03) were significantly smaller in participants with a caudally placed conus medullaris. Multiple regression analysis showed that the pelvic incidence (p < 0.0001) and height (p < 0.0001) were significant factors affecting the conus medullaris level. These results indicated that the length of the spinal cord varies little among individuals and that skeletal differences affect the level of the conus medullaris.

Multisession CyberKnife Radiosurgery for Intramedullary Spinal Cord Arteriovenous Malformations

Neurosurgery ◽  
2006 ◽  
Vol 58 (6) ◽  
pp. 1081-1089 ◽  
Author(s):  
John Sinclair ◽  
Steven D. Chang ◽  
Iris C. Gibbs ◽  
John R. Adler
Keyword(s):  
Magnetic Resonance Imaging ◽  
Spinal Cord ◽  
Magnetic Resonance ◽  
Arteriovenous Malformations ◽  
Conus Medullaris ◽  
Spinal Angiography ◽  
Resonance Imaging ◽  
Intramedullary Spinal Cord ◽  
Cyberknife Radiosurgery

Abstract OBJECTIVE: Intramedullary spinal cord arteriovenous malformations (AVMs) have an unfavorable natural history that characteristically involves myelopathy secondary to progressive ischemia and/or recurrent hemorrhage. Although some lesions can be managed successfully with embolization and surgery, AVM size, location, and angioarchitecture precludes treatment in many circumstances. Given the poor outlook for such patients, and building on the successful experience with radiosurgical ablation of cerebral AVMs, our group at Stanford University has used CyberKnife (Accuray, Inc., Sunnyvale, CA) stereotactic radiosurgery (SRS) to treat selected spinal cord AVMs since 1997. In this article, we retrospectively analyze our preliminary experience with this technique. METHODS: Fifteen patients with intramedullary spinal cord AVMs (nine cervical, three thoracic, and three conus medullaris) were treated by image-guided SRS between 1997 and 2005. SRS was delivered in two to five sessions with an average marginal dose of 20.5 Gy. The biologically effective dose used in individual patients was escalated gradually over the course of this study. Clinical and magnetic resonance imaging follow-up were carried out annually, and spinal angiography was repeated at 3 years. RESULTS: After a mean follow-up period of 27.9 months (range, 3–59 mo), six of the seven patients who were more than 3 years from SRS had significant reductions in AVM volumes on interim magnetic resonance imaging examinations. In four of the five patients who underwent postoperative spinal angiography, persistent AVM was confirmed, albeit reduced in size. One patient demonstrated complete angiographic obliteration of a conus medullaris AVM 26 months after radiosurgery. There was no evidence of further hemorrhage after CyberKnife treatment or neurological deterioration attributable to SRS. CONCLUSION: This description of CyberKnife radiosurgical ablation demonstrates its feasibility and apparent safety for selected intramedullary spinal cord AVMs. Additional experience is necessary to ascertain the optimal radiosurgical dose and ultimate efficacy of this technique.

Ratings gathered online vs. in person

2011 ◽  
Vol 6 (2) ◽  
pp. 325-350
Author(s):  
Lee H. Wurm ◽  
Annmarie Cano ◽  
Diana A. Barenboym
Keyword(s):  
Regression Analysis ◽  
Significant Relationship ◽  
Online Ratings

Barenboym, Wurm, and Cano (2010) recently showed that significant differences emerged for ratings gathered online and in person. They also showed that researchers could reach different statistical conclusions in a regression analysis, depending on whether the norms were gathered online or in person. In the current study that research was extended. Familiarity ratings gathered online were significantly higher than those gathered in the lab, for a set of 300 potential stimuli. The in-person ratings correlated significantly better with an existing database of familiarity values. It is also shown that under three different grouping methods, online and in-person familiarity ratings produce different sets of stimuli. Finally, it is demonstrated that in each case, different conclusions are reached about variables that have a significant relationship with familiarity. Simulations show that the effects are driven disproportionately by higher intra-item variability in the online ratings. Studies in which stimuli are grouped on the basis of ratings can be affected by the choice of rating methodology.

MR imaging of ventriculus terminalis of the conus medullaris: A report of two operated patients and review of the literature

2003 ◽  
Vol 44 (4) ◽  
pp. 444-446
Author(s):  
R. Dullerud ◽  
A. Server ◽  
J. Berg-Johnsen
Keyword(s):  
Spinal Cord ◽  
Mr Imaging ◽  
Signal Intensity ◽  
Incidental Finding ◽  
Conus Medullaris ◽  
Review Of The Literature ◽  
Per Se ◽  
Specific Symptoms ◽  
Work Up

We report on 2 patients in whom a cystic dilation of the conus medullaris was incidentally found at MR imaging carried out in the work-up for sciatica. The cysts were well circumscribed and had signal intensity identical to the CSF on both T1- and T2-weighted images. There was no evidence of contrast enhancement. None of the patients had specific symptoms related to the spinal cord. At surgery, no evidence of malignancy was seen in any of the patients. A benign cystic dilation, also called dilated ventriculus terminalis, occasionally can be seen in the conus medullaris as an incidental finding at thoracolumbar MR imaging. Unless the expansion per se indicates cyst drainage, these patients may be monitored by clinical and MR follow-up, avoiding surgery in a substantial number of cases.

Spinal cord arteriovenous fistulas involving the conus medullaris: presentation, management, and embryologic considerations

1999 ◽  
Vol 52 (1) ◽  
pp. 95-99 ◽  
Author(s):  
Robert W Hurst ◽  
Linda J Bagley ◽  
Paul Marcotte ◽  
Luis Schut ◽  
Eugene S Flamm
Keyword(s):  
Spinal Cord ◽  
Conus Medullaris ◽  
Arteriovenous Fistulas

scholarly journals The Effect of Internal Communication on Employees’ Commitment to Change in Malaysian Large Companies

2017 ◽  
Vol 8 (1) ◽  
pp. 1 ◽  
Author(s):  
Leonis Marchalina ◽  
Hartini Ahmad
Keyword(s):  
Decision Making ◽  
Regression Analysis ◽  
Significant Relationship ◽  
Multivariate Regression ◽  
Multivariate Regression Analysis ◽  
Internal Communication ◽  
Commitment To Change ◽  
Theoretical Contribution ◽  
Structured Questionnaire

Employees’ commitment seems to be vital in decision making for any organizations in order to be able in business competition and to adapt with changes. The commitment among employees can be a crucial tool for improving their performance in organizations. Communication is needed to raise awareness among employees on the need of change as well as creating the readiness to the change whereby it leads to the commitment to change. The objective of this paper is to examine the influence of internal communication on employees’ commitment to change. Apparently, this issue likely has attracted the attention among either scholars or researchers. The theoretical contribution has been added in this study by investigating the effect of internal communication in influencing employees’ commitment to change. A survey of structured questionnaire was conducted in five-hundred fifty employees in Malaysian large companies. The significant relationship has been found between internal communication and employees’ commitment to change through multivariate regression analysis. Moreover, the implications to practice and theory are discussed.

Sign in / Sign up

Export Citation Format

Share Document