Factors affecting internal rotation following total shoulder arthroplasty.

Background: Reverse shoulder arthroplasty (RSA) was developed in the late twentieth century to provide a stable arthroplasty option for patients with rotator cuff deficiency arthropathy. Since its inception, there have been changes in materials, design, and positioning. One of the persistent clinical issues has been difficulty with internal rotation (IR) and the associated difficulty with behind the back activities. Implant design, positioning, and the available soft tissues may influence IR after RSA. The purpose of this systematic review is to assess factors that impact IR following RSA. Methods: The literature search, based on PRISMA guidelines, used 4 databases: Pubmed, Embase, Web of Science, and Cochrane Central Register of Controlled Trials. We included clinical trials that compared different implantation and design modifications and assessed IR. Results: Of the 617 articles identified in the initial search, 46 satisfied the inclusion criteria. The articles explored multiple factors of RSA and their effects on IR, including humeral and glenoid components and muscle function and integrity. Among humeral factors affecting rotation, there was a broad consensus that: IR decreases as retroversion increases, humeral neck-shaft angle less than 155° improves IR, lateralized humeral offset does not improve IR, and shallow cups improve IR. Insert thickness was not associated with a reproducible effect. Of the studies evaluating the effect of glenoid components, there was majority agreement that glenosphere lateralization improved IR, and there were mixed results regarding the effects of glenosphere size and tilt. Others included one study in each: glenoid overhang, retroversion, and baseplate. One study found an association between teres minor insufficiency and improved IR, with mixed results in the presence of fatty infiltration in both teres minor and subscapularis. Most studies noted subscapularis repair had no effect on IR. Conclusion: Prosthetic variables affecting IR are not widely studied. Based on the existing literature, evidence is conflicting. More research needs to be undertaken to gain a greater understanding regarding which factors can be modified to improve IR in RSA patients.

The Association Between Patient Satisfaction and Mode of Visit (Telemedicine Versus In-Person) in a Large Orthopaedic Practice During the COVID-19 Pandemic Lockdown: A Retrospective Study.

BACKGROUND: During the novel coronavirus disease 2019 (COVID-19) pandemic, telemedicine was rapidly adopted to provide continued, efficient, and safe medical care. Little is known about patient satisfaction with telemedicine in orthopedics or the factors associated with selection of telemedicine versus face-to-face care. Thus, we examined (1) the association between patient satisfaction and mode of visit (telemedicine versus in-person) and (2) predictors of patient satisfaction in a large orthopedic practice during the onset of the pandemic. METHODS: We conducted a retrospective cohort study of in-person and telemedicine visits within a large, university-affiliated orthopaedic practice between March 2020 and April 2020 during the onset of the COVID-19 pandemic. Patients who completed a patient satisfaction survey were included. Demographic and other office visit (eg, type of provider and type of visit) data were collected. A Patient Satisfaction Aggregate (PSA, range 0 to 1) score was calculated by taking the average of five patient satisfaction questions. Linear regression was used to examine (1) the association between PSA score and mode of visit and (2) predictors of PSA score. RESULTS: A total of 2,049 of 6,515 patient satisfaction surveys were completed and included for analysis, of which 748 had telemedicine visits and 1,301 had in-person visits. No association was found between PSA score and mode of visit with and without adjustment for duration of patient-physician relationship, appointment type (new versus follow-up), provider type (physician versus nonphysician), and provider subspecialty (ßunadjusted = 0.004 [SE = 0.01], P = 0.44; ßadjusted = 0.001 [SE = 0.01], P = 0.92). Predictors of increased PSA score were White race (P = 0.001), >1 year relationship with provider (P1-3 years = 0.01, P3-5 years = 0.04, and P5+ years = 0.002), physician provider (P = 0.004), and foot/ankle provider (P = 0.04), whereas predictors of decreased PSA score were oncology provider (P = 0.02) and spine provider (P = 0.001). CONCLUSION: We found no association between PSA score and mode of visit. Predictors of PSA score included race, duration of patient-physician relationship, provider type, and provider subspecialty.

The Impact of Anterior Glenoid Defects on Reverse Shoulder Glenoid Fixation in a Composite Scapula Model.

BACKGROUND: Achieving glenoid fixation with anterior bone loss can be challenging. Limited guidelines have been established for critical defect sizes that can be treated without supplemental bone graft when performing reverse shoulder arthroplasty. METHODS: We quantified the impact of two sizes of anterior glenoid defects on glenoid baseplate fixation in a composite scapula using the ASTM F 2028-14 reverse shoulder glenoid loosening test method. RESULTS: All glenoid baseplates remained well-fixed after cyclic loading in composite scapula without a defect and in scapula with an 8.5 mm anterior glenoid defect; however, one of seven baseplates loosened in a scapula with a 12.5 mm defect. No difference was observed between pre- and post-cyclic baseplate displacements in scapula with 8.5 mm or 12.5 mm defects or in the control group scapula. However, baseplate displacement in scapula with 12.5 mm anterior defects was significantly greater after cyclic loading than that of baseplates in 8.5 mm defects (superior-inferior displacement, p = 0.0004; anterior-posterior displacement, p < 0.0001), where baseplate displacement in 8.5 mm (superior- inferior displacement, p = 0.0003; anterior-posterior displacement, p = 0.0014) and 12.5 mm (superior-inferior displacement, p < 0.0001; anterior-posterior displacement, p < 0.0001) defects after cyclic loading was significantly greater than that of baseplates in scapula without a defect. DISCUSSION: Adequate and stable fixation can be achieved in scapula with anterior glenoid defects of at least 8.5 mm in this biomechanical model using an established testing methodology; however, supplemental bone grafting should be utilized for anterior glenoid defects of 12.5 mm and larger using the reverse shoulder prosthesis tested in this study.

Controlled Laboratory Comparison Study of Motion With Football Equipment in a Destabilized Cervical Spine: Three Spine-Board Transfer Techniques.

BACKGROUND: Numerous studies have shown that there are better alternatives to log rolling patients with unstable spinal injuries, although this method is still commonly used for placing patients onto a spine board. No previous studies have examined transfer maneuvers involving an injured football player with equipment in place onto a spine board. PURPOSE: To test 3 different transfer maneuvers of an injured football player onto a spine board to determine which method most effectively minimizes spinal motion in an injured cervical spine model. STUDY DESIGN: Controlled laboratory study. METHODS: Five whole, lightly embalmed cadavers were fitted with shoulder pads and helmets and tested both before and after global instability was surgically created at C5-C6. An electromagnetic motion analysis device was used to assess the amount of angular and linear motion with sensors placed above and below the injured segment during transfer. Spine-boarding techniques evaluated were the log roll, the lift and slide, and the 8-person lift. RESULTS: The 8-person lift technique resulted in the least amount of angular and linear motion for all planes tested as compared with the lift-and-slide and log-roll techniques. This reached statistical significance for lateral bending (P = .031) and medial-lateral translation (P = .030) when compared with the log-roll maneuver. The lift-and-slide technique was significantly more effective at reducing motion than the log roll for axial rotation (P = .029) and lateral bending (P = .006). CONCLUSION: The log roll resulted in the most motion at an unstable cervical injury as compared with the other 2 spine-boarding techniques examined. The 8-person lift and lift-and-slide techniques may both be more effective than the log roll at reducing unwanted cervical spine motion when spine boarding an injured football player. Reduction of such motion is critical in the prevention of iatrogenic injury.

Incidence and etiology of unplanned cast changes for fractures in the pediatric population.

BACKGROUND: The majority of pediatric fractures are treated in casts due to the child's ability to heal rapidly and remodel. Unplanned cast changes are a time and economic burden with potentially adverse effects on fracture management. The purpose of this study is to document the incidence, etiology, and complications related to unplanned cast changes. METHODS: A prospective study was conducted over a 6-month period to determine the incidence of unplanned cast changes. All casts applied were nonwaterproof. Data collected include the reason for cast placement, type of cast placed, duration of wear before the unplanned change, reason for the unplanned change, experience level of the original cast applicator, and cast-related complications. RESULTS: A total of 1135 casts were placed with 58% placed by a resident, 38% by a cast technician, 2% by a physician's assistant, and 2% by an attending physician. Sixty casts (5.3%) required an unplanned change including 19 short-arm casts, 18 short-leg casts, 17 long-arm casts, 4 thumb spica casts, and 2 long-leg casts. The average duration from cast application until the unplanned change was 13 days. Twenty-eight (47%) were changed for wetness, 20 (33%) for wear/breakage, 2 (3%) for skin irritation, and 10 (17%) for other reasons including objects in the cast and patient self-removal. Two patients had superficial skin infections requiring oral antibiotics. No fracture reductions were lost secondary to an unplanned cast change. The need for an unplanned cast change did not correlate with the level of experience of the applicator. CONCLUSIONS: Most unplanned cast changes were the result of patient nonadherence to instructions and not related to cast application technique. Improved patient and family education regarding cast care may reduce the frequency of unplanned cast changes, thus reducing an economic and time burden on the health care system. LEVEL OF EVIDENCE: Level II--prognostic study.

Reverse shoulder glenoid baseplate fixation: a comparison of flat-back versus curved-back designs and oval versus circular designs with 2 different offset glenospheres.

BACKGROUND: In this glenoid loosening study, we compared the fixation strength of multiple generic reverse shoulder glenoid baseplates that differed only in backside geometry and shape and size to optimize design from a fixation perspective. METHODS: The fixation strength of 4 generic baseplates was quantified in a low-density polyurethane substrate to isolate the contribution of baseplate profile and size (25 mm circular vs 25 × 34 mm oval) and backside geometry (flat back vs curved back) on fixation using 2 center-of-rotation glenospheres (0 mm and 10 mm lateral). The cyclic test simulated 55° of abduction as a 750 N load was continuously applied to induce a variable shear and compressive load. Before and after cyclic loading, baseplate displacement was measured in the directions of the applied static shear and compressive loads. Each generic baseplate was cyclically tested 7 times with each offset glenosphere for a total of 56 samples. RESULTS: Circular baseplates were associated with significantly more shear displacement in both the superior-inferior (SI) and anterior-posterior (AP) directions after cyclic loading than oval baseplates. No such significant differences in fixation were observed between flat-back and curved-back baseplates. Circular baseplates were also associated with significantly more SI and AP shear displacement with 10 mm glenospheres than with 0 mm glenospheres. No significant difference in SI or AP motion was observed with oval baseplates between 0 mm and 10 mm glenospheres. DISCUSSION: Our results suggest that baseplate shape and size affects fixation strength more than backside geometry. The 25 × 34 mm oval baseplates showed better fixation characteristics than their 25 mm circular counterparts; no discernible difference in fixation was observed between flat-back and curved-back baseplates.

Reverse shoulder glenoid loosening: an evaluation of the initial fixation associated with six different reverse shoulder designs.

INTRODUCTION: This study quantified glenoid fixation before and after cyclic loading of six reverse shoulder prosthesis designs when secured to low and high density bone substitute blocks. METHODS: A displacement test quantified fixation of six reverse shoulder designs: 38 mm Equinoxe standard offset (EQ), 38 mm Equinoxe lateral offset (EQL), 36 mm Depuy Delta III (DRS), 36 mm Zimmer (ZRS), 32 mm DJO RSP (DJO), and a 36 mm Tornier BIO-RSA (BIO), secured to 0.24 and 0.48 g/cm 3 polyurethane blocks as a shear (357 N) and compressive (50 N) load were applied before and after cyclic loading. Displacement was measured with a dial indicator in the directions of the applied loads along the superior/inferior axis. A cyclic test rotated each glenosphere (N= 7) at 0.5 Hz for 10 k cycles as 750 N was constantly applied. A two-tailed Student's unpaired t-test compared mean displacements. RESULTS: The average displacement of the EQ, EQL, ZRS, DJO, DRS, and BIO-RSA devices in the low density substrate was 182, 137, 431, 321, 190, and 256 microns, respectively. The average displacement of the EQ, EQL, ZRS, DRS, and BIO-RSA devices in the high density substrate was 102, 95, 244, 138, and 173 microns, respectively. Pre- and post-cyclic displacement was significantly less in the high density bone substitutes than in the low density bone substitutes for the majority of implant comparisons. During the cyclic test, six of seven ZRS devices failed at an average of 2,603 cycles, one of seven 32 mm DJO failed at 7,342 cycles, and four of seven BIO devices failed at an average of 2,926 cycles. All seven of the EQ, EQL, and DRS devices remained well fixed throughout cyclic loading. DISCUSSION AND CONCLUSIONS: This study quantified glenoid fixation of six reverse shoulder designs; significant differences in fixation were observed between nearly every implant design tested.

Achieving fixation in glenoids with superior wear using reverse shoulder arthroplasty.

BACKGROUND: Superior glenoid wear is a common challenge with reverse shoulder arthroplasty and, if left uncorrected, can result in superior glenoid tilt, which increases the risk of aseptic glenoid loosening. This study evaluates the impact of an E2 superior defect on reverse shoulder glenoid fixation in composite scapulae after correction of glenoid tilt by use of 2 different glenoid reaming techniques: eccentric reaming and off-axis reaming. MATERIALS AND METHODS: A superior glenoid defect was created in 14 composite scapulae. The superior defect was corrected by 2 different glenoid reaming techniques: (1) eccentric reaming with implantation of a standard glenoid baseplate and (2) off-axis reaming with implantation of a superior-augment glenoid baseplate. Each corrected superior-defect scapula was then cyclically loaded (along with a control group consisting of 7 non-worn scapulae) for 10,000 cycles at 750 N; glenoid baseplate displacement was measured for each group to quantify fixation before and after cyclic loading. RESULTS: Regardless of the glenoid reaming technique or the glenoid baseplate type, each standard and superior-augment glenoid baseplate remained well fixed in this superior-defect model scenario after cyclic loading. No differences in baseplate displacement were observed either before or after cyclic loading between groups. DISCUSSION: Our results suggest that either glenoid reaming technique may be used to achieve fixation in the clinically challenging situation of superior wear with reverse shoulder arthroplasty. LEVEL OF EVIDENCE: Basic science, biomechanical study.

Initial glenoid fixation using two different reverse shoulder designs with an equivalent center of rotation in a low-density and high-density bone substitute.

BACKGROUND: Numerous glenoid implant designs have been introduced into the global marketplace in recent years; however, little comparative biomechanical data exist to substantiate one design consideration over another. MATERIALS AND METHODS: This study dynamically evaluated reverse shoulder glenoid baseplate fixation and compared the initial fixation associated with 2 reverse shoulder designs having an equivalent center of rotation in low-density and high-density bone substitute substrates. RESULTS: Significant differences in fixation were observed between implant designs, where the circular-porous reverse shoulder was associated with approximately twice the micromotion per equivalent test than the oblong-grit-blasted design. Additionally, 6 of the 7 circular-porous reverse shoulders failed catastrophically in the low-density bone model at an average of 2603 ± 981 cycles. None of the oblong-grit-blasted designs failed in the low-or high-density bone models and none of the circular-porous designs failed in the high-density bone models after 10,000 cycles of loading. CONCLUSION: These results demonstrate that significant differences in initial fixation exist between reverse shoulder implants having an equivalent center of rotation and suggest that design parameters, other than the position of the center of rotation, significantly affect fixation in low-density and high-density polyurethane bone substitutes. Subtle changes in glenoid baseplate design can dramatically affect fixation, particularly in low-density bone substitutes that are intended to simulate the bone quality of the recipient population for reverse shoulders.

The impact of scapular notching on reverse shoulder glenoid fixation.

BACKGROUND: Scapular notching is a well-documented complication of reverse shoulder arthroplasty. The effect of scapular notching on glenoid fixation is unknown. MATERIALS AND METHODS: This study dynamically evaluated reverse shoulder glenoid baseplate fixation and assessed the effect of scapular notching on fixation in composite scapulae. A cyclic test was conducted to simulate 55° of humeral abduction in the scapular plane as a 750-N axial load was continuously applied to induce a variable shear and compressive load. Before and after cyclic loading, a displacement test was conducted to measure glenoid baseplate displacement in the directions of the applied static shear and compressive loads. RESULTS: For the scapulae without a scapular notch, glenoid baseplate displacement did not exceed the generally accepted 150-µm threshold for osseous integration before or after cyclic loading in any component tested. For the scapulae with a scapular notch, glenoid baseplate displacement exceeded 150 µm in 2 of the 7 samples before cyclic loading and in 3 of the 7 samples after cyclic loading. The average pre-cyclic glenoid baseplate displacement in the direction of the shear load was significantly greater in scapulae with a scapular notch than those without a scapular notch both before (P = .003) and after (P = .023) cyclic loading. CONCLUSIONS: Adequate glenoid baseplate fixation was achievable in most cases in scapulae with a severe scapular notch; however, the fact that this micromotion threshold was not met in all scapulae with a notch is concerning and implies that severe notching may play a role in initial glenoid baseplate stability.

Outcomes of arthroscopic repair of panlabral tears of the glenohumeral joint.

BACKGROUND: Combined lesions of the glenoid labrum involving tears of the anterior, posterior, and superior labrum have been infrequently reported in the literature. PURPOSE: To evaluate the clinical outcomes of arthroscopic repair of these lesions in a general population using validated scoring instruments, presence of complications, and need for revision surgery. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Fifty-eight patients who had arthroscopic labral repair of tears involving the anterior, posterior, and superior labrum (defined as a panlabral repair) were identified at our institution by retrospective review. All patients underwent arthroscopic labral repair with suture anchor fixation by a uniform approach and with a standardized postoperative protocol. Forty-four patients had a minimum 16-month postoperative follow-up. Outcomes were assessed postoperatively by the American Shoulder and Elbow Surgeons (ASES) score and the Penn Shoulder score. Complications were also documented, including need for revision surgery. RESULTS: The mean age at the time of surgery was 32 years (range, 15-55 years) in the 44 patients. Presenting shoulder complaints included pain alone (40%), instability alone (14%), or pain and instability (45%). Mean number of anchors per repair was 7.9 (range, 5-12). Mean follow-up was 42 months (range, 16-78 months). Mean ± standard deviation ASES score at final follow-up was 90.1 ± 17.7 (range, 22-100), and mean Penn Shoulder score was 90.2 ± 15.3 (range, 38-100). Three of the 4 patients with outcome scores of 70 or less at final follow-up had undergone prior surgery. Thirteen postoperative complications (30%) occurred, with 3 (7%) requiring a second surgery. Five patients (11%) had an instability event following panlabral repair, but only 1 of these patients (2%) required revision surgery for a recurrent labral tear. CONCLUSION: Combined tears of the anterior, posterior, and superior glenoid labrum represent a small but significant portion of labral injuries. Arthroscopic repair of these injuries can be performed with good postoperative outcomes and a low rate of recurrent labral injury.

Management of humeral and glenoid bone loss--associated with glenohumeral instability.

UNLABELLED: Anterior glenohumeral instability complicated by bone loss is a challenging problem and, when severe, may require surgical treatment with bone grafting. We review our institution's experience with humeral head and glenoid bone grafting for large Hill-Sachs lesions and glenoid defects. MATERIALS AND METHODS: Patients who underwent intra-articular bone reconstruction for Hill-Sachs and large glenoid defects for anterior instability at our institution during 2002-2008 were retrospectively reviewed. Those who had undergone concomitant humeral head replacement were excluded. Six patients were identified as having undergone allograft or autograft iliac crest bone graft reconstruction of the glenoid, with four available for full follow-up (average 39 months; range, 7 to 63). Five patients were identified as having undergone humeral head allograft reconstruction and four were available for full follow-up (average 28 months; range, 11 to 40). The remaining three patients were available for telephone follow-up. American Shoulder and Elbow Society (ASES) and University of California, Los Angles (UCLA) scores were recorded and radiographs obtained. RESULTS: Average postoperative ASES and UCLA scores for glenoid bone graft patients were 91 and 33, respectively. Average postoperative ASES and UCLA scores for humeral bone graft patients were 85.3 and 28.4, respectively. Glenoid bone graft shoulders, when compared to the opposite normal side, lost an average of 3° of forward flexion, 10° of external rotation, and two levels of internal rotation. Humeral head bone-grafted shoulders, lost an average of 23° of forward flexion, 8° of external rotation, and two levels of internal rotation. No episodes of recurrent subluxation or dislocations were reported. Radiographs showed no evidence of graft resorption or hardware prominence. CONCLUSIONS: Bone grafting procedures around the shoulder for the treatment of instability provided relief from recurrent instability and good functional results.

Cervical spine motion generated with manual versus jackson table turning methods in a cadaveric c1-c2 global instability model.

STUDY DESIGN.: Cadaveric biomechanical study. OBJECTIVE.: To quantify spinal motion created by transfer methods from supine to prone position in a cadaveric C1-C2 global instability model. SUMMARY OF BACKGROUND DATA.: Patients who have sustained a spinal cord injury remain at high risk for further secondary injury until their spine is adequately stabilized. To date, no study has evaluated the effect of patient transfer methods from supine to prone position in the operating room, on atlantoaxial cervical spine motion. METHODS.: A global instability was surgically created at the C1-C2 level in 4 fresh cadavers. Two transfer protocols were tested on each cadaver. The log-roll technique entailed performing a standard 180 degrees log-roll rotation of the supine patient from a stretcher to the prone position onto the operating room Jackson table (OSI, Union City, CA). The "Jackson technique" involved sliding the supine patient to the Jackson table, securing them to the table, and then rotating them into a prone position. An electromagnetic tracking device registered motion between the C1 and C2 vertebral segments. Three different head holding devices (Mayfield, Prone view, and blue foam pillow) were also compared for their ability to restrict C1-C2 motion. Six motion parameters were tracked. Repeated measures statistical analysis was performed to evaluate angular and translational motion. RESULTS.: For 6 of 6 measures of angulation and translation, manual log-roll prone positioning generated significantly more C1-C2 motion than the Jackson table turning technique. Out of 6 motion parameters, 5 were statistically significant (P < 0.001-0.005). There was minimal difference in C1-C2 motion generated when comparing all 3 head holding devices. CONCLUSION.: The data demonstrate that manual log-roll technique generated significantly more C1-C2 motion compared to the Jackson table technique. Choice of headrest has a minimal effect on the amount of motion generated during patient transfer, except that the Mayfield device demonstrates a slight trend toward increased C1-C2 motion.

Comparison of the flat torso versus the elevated torso shoulder pad removal techniques in a cadaveric cervical spine instability model.

STUDY DESIGN: Controlled laboratory study in a cadaveric model. OBJECTIVE: To determine if removing shoulder pads using the elevated torso technique generated less spinal segment motion than using the flat torso method. SUMMARY OF BACKGROUND DATA: Guidelines for care of the injured football player with a suspected spinal injury recommend initial immobilization with shoulder pads and helmet in place. There is a need to develop a safe protocol, for shoulder pad removal that maintains optimum cervical stability. METHODS: Five lightly embalmed cadavers were studied before and after a globally unstable segment was created at C5-C6. A trained group of medical staff conducted repeated measures trials for 2 pad removal protocols. The elevated torso technique, outlined by the NATA Inter-Association Task Force, is the same as the flat torso except an additional assistant is employed to lift the patient's shoulders 30 degrees to 40 degrees off the ground while the head holder maintains spinal alignment as the pads are removed. An electromagnetic tracking device captured angular and linear motions in 3 planes between the C5-C6 segments. RESULTS: The elevated torso technique generated significantly less C5-C6 motion in flexion/extension (P = 0.015) and lateral bending (P = 0.001), with a trend toward decreased cervical motion in axial rotation (P = 0.052). When moving the spine-injured cadavers, linear translation was also slightly, but not significantly less when the elevated torso technique was used. In the intact spine, significantly less motion was seen in 5 of 6 measures when the elevated torso technique was used. However, the differences were not large enough to be clinically significant in an intact spine. CONCLUSION: These findings support use of the elevated torso method to minimize cervical spine motion during shoulder pad removal when neither thoracic nor lumbar spinal injury is a concern.

Comparing cervical spine motion with different halo devices in a cadaveric cervical instability model.

STUDY DESIGN: Biomechanical evaluation of conventional and noninvasive halos in cadaveric C1-C2 and C5-C6 instability models. OBJECTIVE: To compare the ability of a conventional halo and noninvasive halo (NIH) to immobilize the unstable cervical spine at the C1-C2 and C5-C6 levels. SUMMARY OF BACKGROUND DATA: Many successful outcomes have been reported in cervical spine injury treatment with the conventional halo (CH); however, complications related to pin sites have been reported. The NIH was designed to overcome these complications. To date, no investigation has compared the biomechanical efficacy of the NIH with that of the CH in restricting three-dimensional cervical spine motion. METHODS: A global instability was created at the C1-C2 level in 4 cadavers and at C5-C6 in 4 others. Relative motion was measured between the superior and inferior vertebrae during the donning process, execution of the log roll technique, and during the process of sitting up. This testing sequence was followed for all treatment conditions. RESULTS: During the application of the orthoses there was a significant increase in motion at C1-C2 instability and a trend toward increased motion at the C5-C6 instability with CH compared with NIH. In the log roll maneuver, the CH and NIH restrict motion to a similar degree at the C1-C2 instability level, except in frontal plane translation, where CH immobilizes the segment to a greater extent. For the C5-C6 instability the CH provides significantly better immobilization for lateral bending and axial translation. No significant differences were found between the NIH and CH for the sit-up maneuver at either of the levels. CONCLUSION: Donning of the NIH generates significantly less cervical spine motion than application of the CH. The CH provides superior immobilization for a C5-C6 instability during the log roll maneuver and a C1-C2 instability in the frontal plane during the log-roll maneuver. The CH and NIH immobilize the C1-C2 and C5-C6 instability to a similar degree during the sit-up maneuver.

Comparison of thoracolumbar motion produced by manual and Jackson-table-turning methods. Study of a cadaveric instability model.

BACKGROUND: Patients who have sustained a spinal cord injury remain at risk for further neurologic deterioration until the spine is adequately stabilized. To our knowledge, no study has previously addressed the effects of different bed-to-operating room table transfer techniques on thoracolumbar spinal motion in an instability model. We hypothesized that the conventional logroll technique used to transfer patients from a supine position to a prone position on the operating room table has the potential to confer significantly more motion to the unstable thoracolumbar spine than the Jackson technique. METHODS: Three-column instability was surgically created at the L1 level in seven cadavers. Two protocols were tested. The manual technique entailed performing a standard logroll of a supine cadaver to a prone position on an operating room Jackson table. The Jackson technique involved sliding the supine cadaver to the Jackson table, securing it to the table, and then rotating it into a prone position. An electromagnetic tracking device measured motion--i.e., angular motion (flexion-extension, lateral bending, and axial rotation) and linear translation (axial, medial-lateral, and anterior-posterior) between T12 and L2. RESULTS: The logroll technique created significantly more motion than the Jackson technique as measured with all six parameters. Manual logroll transfers produced an average of 13.8 degrees to 18.1 degrees of maximum angular displacement and 16.6 to 28.3 mm of maximum linear translation. The Jackson technique resulted in an average of 3.1 degrees to 5.8 degrees of maximum angular displacement (p < 0.001) and 4.0 to 10.0 mm of maximum linear translation (p < 0.05). CONCLUSIONS: Compared with the logroll, the Jackson-table transfer method provides superior immobilization of an unstable thoracolumbar spine during transfer of supine cadavers to a prone position on the operating room table. CLINICAL RELEVANCE: This study addresses in-hospital patient safety. Performing the Jackson turn requires approximately half as many people as required for a manual logroll. This study suggests that the Jackson technique should be considered for supine-to-prone transfer of patients with known or suspected instability of the thoracolumbar spine.

Transferring patients with thoracolumbar spinal instability: are there alternatives to the log roll maneuver?

STUDY DESIGN: Using a cadaveric model, the amount of spinal motion generated during the execution of various prehospital transfer techniques was evaluated using a crossover study design. OBJECTIVE: To assess the quantity of segmental motion generated across a globally unstable thoracolumbar spine during the execution of the log roll (LR), lift-and-slide, and 6-plus-person (6+) lift. SUMMARY OF BACKGROUND DATA: The LR has been reported to be inappropriate for transferring patients with thoracolumbar injuries. Although potentially safer methods have been identified for use with cervical spine injuries, alternatives to the LR have not been recognized in the case of thoracolumbar injuries. METHODS.: Three-dimensional angular motion was recorded across the T12-L2 vertebrae during execution of 3 transfer techniques using cadavers with intact spines and then repeated following an L1 corpectomy. Using a three-dimensional electromagnetic tracking device, the maximum angular motion was measured 3 times for each technique, and the mean value from the 3 trials was included in the statistical analysis. RESULTS: Statistical tests revealed that there was a significant difference in axial rotation between the LR and lift-and-slide (P = 0.008) but only when these were executed in the presence of a destabilized T12-L1 segment. In addition, analysis of lateral flexion data identified a main effect for technique with the LR generating greater motion than either lifting technique. Finally, no significant difference was noted for flexion-extension among techniques. CONCLUSION: The execution of the LR maneuver tends to generate more motion than either of the lifting methods examined in this investigation. More research is needed to identify the safest possible method for transferring or moving patients with thoracolumbar instability.

Cervical spine motion in manual versus Jackson table turning methods in a cadaveric global instability model.

STUDY DESIGN: A study of spine biomechanics in a cadaver model. OBJECTIVE: To quantify motion in multiple axes created by transfer methods from stretcher to operating table in the prone position in a cervical global instability model. SUMMARY OF THE BACKGROUND DATA: Patients with an unstable cervical spine remain at high risk for further secondary injury until their spine is adequately surgically stabilized. Previous studies have revealed that collars have significant, but limited benefit in preventing cervical motion when manually transferring patients. The literature proposes multiple methods of patient transfer, although no one method has been universally adopted. To date, no study has effectively evaluated the relationship between spine motion and various patient transfer methods to an operating room table for prone positioning. METHODS: A global instability was surgically created at C5-6 in 4 fresh cadavers with no history of spine pathology. All cadavers were tested both with and without a rigid cervical collar in the intact and unstable state. Three headrest permutations were evaluated Mayfield (SM USA Inc), Prone View (Dupaco, Oceanside, CA), and Foam Pillow (OSI, Union City, CA). A trained group of medical staff performed each of 2 transfer methods: the "manual" and the "Jackson table" transfer. The manual technique entailed performing a standard rotation of the supine patient on a stretcher to the prone position on the operating room table with in-line manual cervical stabilization. The "Jackson" technique involved sliding the supine patient to the Jackson table (OSI, Union City, CA) with manual in-line cervical stabilization, securing them to the table, then initiating the table's lock and turn mechanism and rotating them into a prone position. An electromagnetic tracking device captured angular motion between the C5 and C6 vertebral segments. Repeated measures statistical analysis was performed to evaluate the following conditions: collar use (2 levels), headrest (3 levels), and turning technique (2 levels). RESULTS: For all measures, there was significantly more cervical spine motion during manual prone positioning compared with using the Jackson table. The use of a collar provided a slight reduction in motion in all the planes of movement; however, this was only significantly different from the no collar condition in axial rotation. Differences in gross motion between the headrest type were observed in lateral bending (Foam Pillow