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P60. Effects of cervical flexion distraction deformities on the patency of the vertebral arterial vasculature
138S
Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S
METHODS: The following possible risk factors for the radiographic failure were assessed by multivariate logistic regression analysis: age, gender, degree of vertebral body collapse in both sagittal and axial plane, magnitude of kyphosis correction, levels of injuries, extent of fusion area, and types of fixation devices. Degree of vertebral body collapse was evaluated by the scoring system proposed by McCormack et al. in which “comminution score” in sagittal plane and “apposition score” in axial plane were independently graded from 1 to 3 points in order of severity. RESULTS: Significant correction loss (10 or more degrees) of kyphotic deformity occurred in 22 (48%) of 45 patients. In these 22 patients, an average correction loss was 14 degrees ranging from 10 to 27 degrees. The following important risk factors for the radiographic failure of the standalone posterior reconstruction were detected by multivariate logistic regression analysis: (1) degree of vertebral body comminution in axial plane (odds ratio per 1 point increase in apposition score: 16.9, p⫽.0023); and (2) levels of injuries (odds ratio of thoracolumbar/lumbar injuries: 152.2, p⫽.0107). Other factors such as extent of fusion area or types of fixation devices were proved to be insignificant. Predicted probabilities of the radiographic failure for thoracolumbar/lumbar spinal injuries with 2 or 3 points in apposition score were calculated to be 0.80 to 0.98. CONCLUSIONS: In the thoracolumbar and lumbar spine, anterior column reconstruction was mandatory for not only burst fractures but fracturedislocations with moderate to severe vertebral body comminution. Pedicle screw fixation with or without claw hooks placement or extending fusion area was not an effective solution to avoid radiographic failure following the stand-alone posterior reconstruction for thoracolumbar spinal injuries with anterior column insufficiency. DISCLOSURES: FDA device/drug: Isola. Status: Approved for this indication. FDA device/drug: Steffee VSP. Status: Approved for this indication. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.273 P59. Assessing lumbar sagittal motion using videography in an in vivo pilot study S. Craig Humphreys, MD1, Scott Hodges, DO1, Kelly Lumpkin, MS1, Jason Eck, DO, MS2, Rebecca Wurster, BS1, Justin Hagen, BS1, Danielle Farmer1, Jay Jolley, II, MD1; 1Center for Sports Medicine and Orthopaedics, Chattanooga, TN, USA; 2Memorial Hospital, York, York, PA, USA BACKGROUND CONTEXT: There is currently limited data regarding the number of cycles the spine undergoes during a given time period. PURPOSE: This in vivo pilot study was conducted to assess lumbar sagittal plane motion utilizing noninvasive and inexpensive ve´rite´ videography. STUDY DESIGN/SETTING: Routine work day environment. PATIENT SAMPLE: Five participants of differing occupations during a routine work day. OUTCOME MEASURES: Number of full and partial sagittal plane movements furing a four hour period. METHODS: Five participants of differing occupations were filmed using two video cameras at different angles during four hours of uninhibited ergonomic activities. Three independent viewers observed each recording and classified each sagittal plane movement as one-third, two-third, or full bend. A post-viewing collaborative meeting was utilized to verify results among the three viewers. RESULTS: ANOVA revealed statistically significant differences in both the number and types of sagittal plane movement among subjects of different occupations (p⬍.001). Subjects performed less full bends (M⫽120, SD⫽82.85) than one-third (M⫽285.20, SD⫽114.15) and two-thirds (M⫽240.33 SD⫽134.03). Inter-rater reliability among viewers was r⫽0. 91. Pearson’s correlations revealed viewers could consistently watch video recordings of different occupations and establish similar numbers of onethird, two-third and full bends (r⫽0.83 to 0.99). Extrapolation of the data predicted a range of 420 to1,980 full bends during a forty-hour workweek, and 218,400 to 1,029,600 extreme bends during working hours over a ten year period if the constant remained.
CONCLUSIONS: Quantifying sagittal motion with two-dimensional video analysis appears to be a reliable method. Extent of bending within occupations appeared to be different; however, results were not reflective of general assumptions about activity levels in each occupation. Occupations perceived as sedentary such as receptionist and medical records personnel produced greater numbers of bends than the physical therapy technician, although, the number of participants in this study was limited. All activities of daily living will need to be accounted for to provide an accurate projection of spinal movement. Reliably estimating spinal motion cycles will be necessary for the development of biomechanical studies of wear and fatigue testing in the emerging technology of spinal arthroplasty. It is hoped that this pilot data will allow for future studies to better define the cyclic motion patterns of the lumbar spine. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: Author (SCH) Grant Research Support: Medtronic Sofamor Danek. doi: 10.1016/j.spinee.2005.05.274
P60. Effects of cervical flexion distraction deformities on the patency of the vertebral arterial vasculature Ernst Sim, MD; UKH–Meidling, Vienna, Austria BACKGROUND CONTEXT: Asymptomatic vertebral artery injury is found in up to 19% of all patients who incur trauma to the lower cervical spine. This incidence increases in flexion–distraction injuries. It is unclear as to the individual contributions of various force loads and resultant deformity on the etiology of these injuries. PURPOSE: To evaluate the degree of vertebral vessel deformation and potential injury in staged flexion–distraction deformities of the cervical spine. STUDY DESIGN/SETTING: Thirty-five fresh frozen cervical spine specimens underwent vertebral artery cannulization and angiography to determine the static influence of the four stages of subaxial flexion–distraction injuries as described by Allen et al. on vertebral artery patency. PATIENT SAMPLE: The patency of vertebral artery patency was studied in thirty–five specimens. OUTCOME MEASURES: To evaluate the degree of vertebral vessel deformation and potential injury in staged static flexion–distraction deformities of the cervical spine. METHODS: Each specimen was examined radiographically so as to exclude any preexisting cervical deformities. A cannula was inserted into the isolated cranial and caudal stumps of the vertebral arteries and perfused with contrast agent. A fluoro image intensifier recorded deformations in dye fluid passage in the four stages of flexion–distraction injuries. RESULTS: No significant deformation in vertebral artery flow was noted in the flexion–distraction Stage I injuries within the physiologic range of cervical flexion. Flexion–distraction Type II and III injuries (unilateral and bilateral facet dislocations, respectively) demonstrated considerable impairment to vertebral artery dye flow in proportion to the degree of vertebral deformity. Manipulating the dislocated vertebral segments into a localized lordosis(flexion–distraction Stage II) further impaired vertebral vessel patency. Coexisting rupture of the vertebral radicular vessel was a constant finding in Stage II and III injuries. Longitudinal stretch deformities of the vertebral artery were limited primarily to the injured vertebral segment. Stage IV injuries resulted in irreversible disruption of vertebral dye flow. CONCLUSIONS: The static deformity of flexion–distraction Stage II to IV subaxial cervical injuries results in significant objective compression of the vertebral vasculature. The precise contribution of static cervical malalignment related to advanced staged flexion–distraction injuries on irreversible vertebral vessel flow disruption is presently uncertain DISCLOSURES: FDA device/drug: Iopamiro. Status: Approved for this indication. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.275
Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S
METHODS: The following possible risk factors for the radiographic failure were assessed by multivariate logistic regression analysis: age, gender, degree of vertebral body collapse in both sagittal and axial plane, magnitude of kyphosis correction, levels of injuries, extent of fusion area, and types of fixation devices. Degree of vertebral body collapse was evaluated by the scoring system proposed by McCormack et al. in which “comminution score” in sagittal plane and “apposition score” in axial plane were independently graded from 1 to 3 points in order of severity. RESULTS: Significant correction loss (10 or more degrees) of kyphotic deformity occurred in 22 (48%) of 45 patients. In these 22 patients, an average correction loss was 14 degrees ranging from 10 to 27 degrees. The following important risk factors for the radiographic failure of the standalone posterior reconstruction were detected by multivariate logistic regression analysis: (1) degree of vertebral body comminution in axial plane (odds ratio per 1 point increase in apposition score: 16.9, p⫽.0023); and (2) levels of injuries (odds ratio of thoracolumbar/lumbar injuries: 152.2, p⫽.0107). Other factors such as extent of fusion area or types of fixation devices were proved to be insignificant. Predicted probabilities of the radiographic failure for thoracolumbar/lumbar spinal injuries with 2 or 3 points in apposition score were calculated to be 0.80 to 0.98. CONCLUSIONS: In the thoracolumbar and lumbar spine, anterior column reconstruction was mandatory for not only burst fractures but fracturedislocations with moderate to severe vertebral body comminution. Pedicle screw fixation with or without claw hooks placement or extending fusion area was not an effective solution to avoid radiographic failure following the stand-alone posterior reconstruction for thoracolumbar spinal injuries with anterior column insufficiency. DISCLOSURES: FDA device/drug: Isola. Status: Approved for this indication. FDA device/drug: Steffee VSP. Status: Approved for this indication. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.273 P59. Assessing lumbar sagittal motion using videography in an in vivo pilot study S. Craig Humphreys, MD1, Scott Hodges, DO1, Kelly Lumpkin, MS1, Jason Eck, DO, MS2, Rebecca Wurster, BS1, Justin Hagen, BS1, Danielle Farmer1, Jay Jolley, II, MD1; 1Center for Sports Medicine and Orthopaedics, Chattanooga, TN, USA; 2Memorial Hospital, York, York, PA, USA BACKGROUND CONTEXT: There is currently limited data regarding the number of cycles the spine undergoes during a given time period. PURPOSE: This in vivo pilot study was conducted to assess lumbar sagittal plane motion utilizing noninvasive and inexpensive ve´rite´ videography. STUDY DESIGN/SETTING: Routine work day environment. PATIENT SAMPLE: Five participants of differing occupations during a routine work day. OUTCOME MEASURES: Number of full and partial sagittal plane movements furing a four hour period. METHODS: Five participants of differing occupations were filmed using two video cameras at different angles during four hours of uninhibited ergonomic activities. Three independent viewers observed each recording and classified each sagittal plane movement as one-third, two-third, or full bend. A post-viewing collaborative meeting was utilized to verify results among the three viewers. RESULTS: ANOVA revealed statistically significant differences in both the number and types of sagittal plane movement among subjects of different occupations (p⬍.001). Subjects performed less full bends (M⫽120, SD⫽82.85) than one-third (M⫽285.20, SD⫽114.15) and two-thirds (M⫽240.33 SD⫽134.03). Inter-rater reliability among viewers was r⫽0. 91. Pearson’s correlations revealed viewers could consistently watch video recordings of different occupations and establish similar numbers of onethird, two-third and full bends (r⫽0.83 to 0.99). Extrapolation of the data predicted a range of 420 to1,980 full bends during a forty-hour workweek, and 218,400 to 1,029,600 extreme bends during working hours over a ten year period if the constant remained.
CONCLUSIONS: Quantifying sagittal motion with two-dimensional video analysis appears to be a reliable method. Extent of bending within occupations appeared to be different; however, results were not reflective of general assumptions about activity levels in each occupation. Occupations perceived as sedentary such as receptionist and medical records personnel produced greater numbers of bends than the physical therapy technician, although, the number of participants in this study was limited. All activities of daily living will need to be accounted for to provide an accurate projection of spinal movement. Reliably estimating spinal motion cycles will be necessary for the development of biomechanical studies of wear and fatigue testing in the emerging technology of spinal arthroplasty. It is hoped that this pilot data will allow for future studies to better define the cyclic motion patterns of the lumbar spine. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: Author (SCH) Grant Research Support: Medtronic Sofamor Danek. doi: 10.1016/j.spinee.2005.05.274
P60. Effects of cervical flexion distraction deformities on the patency of the vertebral arterial vasculature Ernst Sim, MD; UKH–Meidling, Vienna, Austria BACKGROUND CONTEXT: Asymptomatic vertebral artery injury is found in up to 19% of all patients who incur trauma to the lower cervical spine. This incidence increases in flexion–distraction injuries. It is unclear as to the individual contributions of various force loads and resultant deformity on the etiology of these injuries. PURPOSE: To evaluate the degree of vertebral vessel deformation and potential injury in staged flexion–distraction deformities of the cervical spine. STUDY DESIGN/SETTING: Thirty-five fresh frozen cervical spine specimens underwent vertebral artery cannulization and angiography to determine the static influence of the four stages of subaxial flexion–distraction injuries as described by Allen et al. on vertebral artery patency. PATIENT SAMPLE: The patency of vertebral artery patency was studied in thirty–five specimens. OUTCOME MEASURES: To evaluate the degree of vertebral vessel deformation and potential injury in staged static flexion–distraction deformities of the cervical spine. METHODS: Each specimen was examined radiographically so as to exclude any preexisting cervical deformities. A cannula was inserted into the isolated cranial and caudal stumps of the vertebral arteries and perfused with contrast agent. A fluoro image intensifier recorded deformations in dye fluid passage in the four stages of flexion–distraction injuries. RESULTS: No significant deformation in vertebral artery flow was noted in the flexion–distraction Stage I injuries within the physiologic range of cervical flexion. Flexion–distraction Type II and III injuries (unilateral and bilateral facet dislocations, respectively) demonstrated considerable impairment to vertebral artery dye flow in proportion to the degree of vertebral deformity. Manipulating the dislocated vertebral segments into a localized lordosis(flexion–distraction Stage II) further impaired vertebral vessel patency. Coexisting rupture of the vertebral radicular vessel was a constant finding in Stage II and III injuries. Longitudinal stretch deformities of the vertebral artery were limited primarily to the injured vertebral segment. Stage IV injuries resulted in irreversible disruption of vertebral dye flow. CONCLUSIONS: The static deformity of flexion–distraction Stage II to IV subaxial cervical injuries results in significant objective compression of the vertebral vasculature. The precise contribution of static cervical malalignment related to advanced staged flexion–distraction injuries on irreversible vertebral vessel flow disruption is presently uncertain DISCLOSURES: FDA device/drug: Iopamiro. Status: Approved for this indication. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.275