Faculty Bibliography

STUDY DESIGN: Prospective, randomized, controlled animal study. OBJECTIVE: To determine the efficacies of 2 ceramic composite bone graft extenders for promoting spinal fusion. SUMMARY OF BACKGROUND DATA: Although autogenous bone is still considered the "gold standard" graft material for fusion procedures, its use is associated with a number of limitations. Synthetic ceramic composites represent a class of osteoconductive materials that may be employed as supplements or even alternatives to autograft. In this study, we compared the fusion rates generated by 2 ceramic composite bone graft extenders (MasterGraft and Mozaik Strips) with that obtained with autograft in a rabbit bone paucity model. METHODS: Thirty-two New Zealand white rabbits undergoing noninstrumented posterolateral lumbar fusion were randomized to 1 of the following 4 groups: 100% autograft, 50% autograft, 50% autograft with Mozaik Strip, and 50% autograft with MasterGraft Strip. The rabbits were followed postoperatively for 8 weeks at which time the spinal segments were explanted and assessed for the presence of a solid fusion. RESULTS: The arthrodesis rates by manual palpation of the 100% and 50% autograft controls were 75% (6 of 8 animals) and 12.5% (1 of 8), respectively (P < 0.01). In the 50% autograft/Mozaik and 50% autograft/MasterGraft groups, 3/8 and 1/8 of the rabbits were determined to have fused successfully, respectively (P = 0.569). However, there were no significant differences between the fusion rate of the 50% autograft cohort and those exhibited by the Mozaik or MasterGraft animals (P = 0.569 and 1.00, respectively). CONCLUSION: This study provides further evidence that the quantity of autograft may influence the process of spinal fusion such that the arthrodesis rate was significantly lower when less bone was implanted. Neither of the ceramic composite scaffolds seemed to enhance the fusion response compared to an equivalent amount of autograft alone, suggesting that these substances may need to be combined with other osteogenic materials to optimize bone production.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To quantify which 3 common lumbar orthoses of varying rigidity restrict both full, active range of motion (ROM) and functional ROM required for activities of daily living (ADL). SUMMARY OF BACKGROUND DATA: Spinal orthoses are implemented to restrict lumbar motion. Despite widespread prevalence of lumbar bracing, the efficacy of these appliances for immobilizing the spine has not been definitively established. METHODS: The full, active ROM of 10 asymptomatic individuals was quantified using an electrogoniometer that registered maximum rotation in all planes. Subjects subsequently completed 15 simulated ADLs during which time their functional ROM was measured; performed without a brace and while wearing a corset, semirigid lumbosacral orthosis (LSO), and rigid custom-molded LSO. RESULTS: For flexion/extension, the mean percentage decreases (with SDs) in full, active ROM that were recorded with corset, semirigid, and a custom orthosis were 24.1 +/- 7.9%, 46.8 +/- 7.1%, and 64.7 +/- 8%, respectively (P < 0.001 relative to no brace). In the coronal plane, motion was restricted by 33.9 +/- 8.8%, 51.9 +/- 9.4%, and 49.1 +/- 11.8%, respectively (P < 0.001). Finally, rotation was limited by 39.6 +/- 8.8%, 59.2 +/- 10.2%, and 70.6 +/- 5.4%, respectively (P < 0.001). There were no significant discrepancies between the ROM recorded in the semirigid and custom LSOs for the ADLs. Likewise, functional ROM associated with corset and semirigid LSOs were only different for 2 ADLs whereas significant disparities between values with corset and custom LSOs were observed for 4 simulations. CONCLUSION: The full, active ROM allowed by lumbar braces evaluated was greater than employed during ADLs in absence of any brace. The motion decrease beyond actual restriction of the braces suggests they will act primarily as proprioceptive guides to regulate movement.

STUDY DESIGN: Laboratory biomechanical experiment. OBJECTIVE: To evaluate how different anterior cervical collar heights restrict full, active range of motion (ROM), and functional ROM during 15 activities of daily living. SUMMARY OF BACKGROUND DATA: Hard cervical collars are commonly used in the clinical setting. Collar fit is presumed to affect immobilization, making neck height an important variable. No prior study has evaluated how different collar heights affect full, active and functional ROM. METHODS: A previously validated electrogoniometer device was employed to quantify both full, active, and functional ROM. For each of 10 subjects, these ROM measurements were repeated without a collar and with an adjustable, hard collar (Aspen Vista) at each of 6 collar neck height settings. RESULTS: For each increase in collar height, there was a corresponding decrease in mean full, active ROM of 3.7% (3 degrees ) in the sagittal plane (R2 = 0.91, P = 0.003), 3.9% (3 degrees ) in the coronal plane (R2 = 0.88, P = 0.005), and 2.8% (4 degrees ) in the rotational plane (R2 = 0.86, P = 0.006). For each increase in collar height, there was a corresponding decrease in mean functional ROM across all of the tested activities of daily living of 1.1% (1 degrees ) in the sagittal plane (R2 = 0.90, P = 0.004), 0.4% (0.4 degrees ) in the coronal plane (R2 = 0.86, P = 0.007), and 0.6% (0.5 degrees ) in the rotational plane (R2 = 0.81, P = 0.014). For each increase in collar height, there was a 1.7 degrees increase in mean neck extension while in the neutral position (R2 = 0.99, P < 0.001). CONCLUSION: This study suggests that greater cervical collar height for hard cervical collars will better restrict full, active, and functional cervical ROM. However, the change in functional ROM was only about one quarter to that of full active ROM and the clinical significance of this may be questioned. This must be balanced by the fact that this increased collar height forces the neck into greater extension which may not be the most clinical desired or functional position and may cause skin-related issues at the jaw or chest.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To evaluate the relative efficacies of soft and rigid collars for restricting both the full, active and functional ranges of motion (ROM) of the cervical spine during 15 activities of daily living (ADLs). SUMMARY OF BACKGROUND DATA: Cervical collars are frequently used for the purpose of limiting cervical motion after surgical procedures or as a treatment for certain injuries. Rigid collars are generally believed to reduce cervical motion to a greater extent than soft collars but the latter are often preferred by patients because of their greater comfort. Although there are some data to suggest that soft collars restrict full, active ROM (i.e., the extremes of motion) to a lesser degree than rigid braces, there are currently no comparative studies that have assessed the effects of these 2 types of cervical collars on the functional ROM that is required to perform multiple ADLs. METHODS: In this investigation, a previously validated electrogoniometer device was used to quantify both the full, active ROM of 10 subjects as well as the functional ROM they exhibited during a series of 15 ADLs. For each individual, these ROM measurements were repeated after the application of both a soft collar and a rigid orthosis. RESULTS: The soft collar limited flexion/extension, lateral bending, and rotation by 27.1%+/-9.9% (mean+/-standard deviation), 26.1%+/-4.8%, and 29.3%+/-10.3%, respectively. The corresponding reductions in ROM with a rigid collar were 53.7%+/-7.2%, 34.9%+/-6%, and 59.2%+/-5.3%, respectively. The rigid collar resulted in significantly lower full, active ROM in both the sagittal and axial planes but not in the lateral bending plane. Compared with the soft collar, the rigid collar afforded no difference in motion during 13 of the 15 simulated ADLs. Greater motion was only noted with backing up a car and sitting from a standing position. CONCLUSION: Although subjects exhibited less full, active ROM of the cervical spine when immobilized in a rigid collar than when they were placed in a soft collar, the motion recorded during various functional tasks was not significantly different for nearly all of the ADLs in this study, regardless of which cervical device was applied. One potential explanation for this finding is that both collars may serve as proprioceptive guides, which allow patients to regulate their own cervical motion based on their level of comfort. Given the paucity of data supporting the use of postoperative bracing, especially after procedures which incorporate internal fixation, this study indicates that a rigid orthosis may be unnecessary in many cases because even a soft collar seems to be sufficient for restricting motion during routine activities until the normal, physiologic ROM of the cervical spine has been restored.