Significant Differences In Rotation Research Articles

Seminal vesicle intrafraction motion during the delivery of radiotherapy sessions on a 1.5 T MR-Linac

To evaluate seminal vesicle (SV) intrafraction motion using cinematic magnetic resonance imaging (cine-MR) during the delivery of online adaptive MR-Linac radiotherapy fractions, in preparation of MR-guided extremely hypofractionated radiotherapy for intermediate to high-risk prostate cancer patients. Fifty prostate cancer patients were treated with 5×7.25Gy on a 1.5 Tesla MR-Linac. 3D Cine-MR imaging was started simultaneously and acquired over the full beam-on period. Intrafraction motion in this cine-MR was determined for each SV separately with a previously validated soft-tissue contrast-based tracking algorithm. Motion statistics and coverage probability for the SVs and prostate were determined based on the obtained results. SV motion was automatically determined during the beam-on period (approx. 10min) for 247 fractions. SV intrafraction motion shows larger spread than prostate intrafraction motion and increases over time. This difference is especially evident in the anterior and cranial translation directions. Significant difference in rotation about the left-right axis was found, with larger rotation for the SVs than the prostate. Intra-fraction coverage probability of 99% can be achieved when using 5mm isometric expansion for the left and right SV and 3mm for the prostate. This is the first study to investigate SV intrafraction motion during MR-guided RT sessions on an MR-Linac. We have shown that high quality 3D cine-MR imaging and SV tracking during RT is feasible with beam-on. The tracking method as described may be used as input for a fast replanning algorithm, which allows for intrafraction plan adaptation.

Biomechanical Evaluation of Suture Button Spread with and without Deltoid Repair in Combined Syndesmosis and Deltoid Injury

Category:Sports; Basic Sciences/BiologicsIntroduction/Purpose:Syndesmosis injuries are common and frequently occur with deltoid injuries but optimal repair remains controversial. Prior biomechanical studies have demonstrated that 1 and 2 suture buttons are equivalent to screw fixation and that parallel or divergent suture buttons are equivalent to single suture button. Prior studies, however, created constructs with suture buttons within 1cm from each other (2-3cm from joint surface). Additionally, the role of deltoid injury and repair have not been evaluated in conjunction with syndesmosis injury and repair. The purpose of this study was to biomechanically compare a narrow vs spread 2-suture button construct with and without a deltoid repair.Methods:Four matched lower leg specimens (8 total specimens) aged mean 60.2 years (range 57-66 years; 6 females and 2 males; mean BMI 21.1) were tested. Ankle motion under cyclic loading was measured in multiple planes: first in the intact state, following simulated syndesmosis and deltoid injury, then following fixation with 1 of 2 randomly assigned constructs: 2 parallel suture buttons at 2 and 3cm from joint line (narrow); and 2 parallel suture buttons at 1 and 4cm from joint line (spread), and then finally following a deltoid repair with each construct. Each state was tested at a constant 750 N axial compressive force and 5N internal/external torque. Rotation position (degrees) and anterior-posterior displacement (mm) were collected throughout the testing to characterize relative spatial relationships of the tibiofibular articulation using 3D video capture technology.Results:Narrow and spread 2-suture button constructs improved rotation and translation compared to cut state (p<0.05) but not to intact state (p>0.05). There were no significant differences in rotation or translation between Narrow and Spread constructs (p>0.05). The addition of a deltoid repair did not improve rotation or translation compared to syndesmosis repair with either construct alone (p>0.05).Conclusion:The preliminary results of this study suggest that constructs with suture button placed close together or spread apart during fixation of combined syndesmosis and deltoid injury could improve rotation and translation equally. Additionally, in a combined syndesmosis and deltoid injury, the addition of a deltoid repair to a syndesmosis repair did not strengthen the construct. These findings suggest that repair of syndesmosis alone may be sufficient in combined syndesmosis and deltoid injuries. Additional matched samples will be tested to validate preliminary findings.

Complete Capsular Repair Restores Native Kinematics After Interportal and T-Capsulotomy

Background: Although the use of hip arthroscopy continues to increase, capsular management remains a controversial topic. Purpose: To investigate the biomechanical effect of capsulotomy and capsular repair techniques on hip joint kinematics in varying combinations of sagittal and coronal joint positions. Study Design: Controlled laboratory study. Methods: Eight fresh-frozen hemi-pelvises (78.3 ± 6.0 years of age; 4 left, 6 male) were dissected of all overlying soft tissue, with the exception of the hip joint capsule. The femur was potted and attached to a load cell, while the pelvis was secured to a custom-designed fixture allowing static alteration of the flexion-extension arc. Optotrak markers were rigidly attached to the femur and pelvis to track motion of the femoral head with respect to the acetabulum. After specimen preparation, 7 conditions were tested: (1) intact, (2) after portal placement (anterolateral and midanterior), (3) interportal capsulotomy (IPC) (35 mm in length), (4) IPC repair, (5) T-capsulotomy (IPC +15-mm longitudinal incision), (6) partial T-repair (repair of longitudinal incision with IPC left open), (7) full T-repair. All conditions were tested in 15° of extension (–15°), 0°, 30°, 60°, and 90° of flexion. Additionally, all flexion angles were tested in neutral, as well as in specimen-specific maximum abduction and adduction, resulting in 15 testing positions. Internal rotation (IR) and external rotation (ER) moments of 3 N·m were manually applied to the femur via the load cell at each position. Rotational range of motion and joint kinematics were recorded. Results: In the neutral coronal plane, T-capsulotomy significantly increased IR/ER rotational range of motion compared with intact state at −15° (55.96°± 6.11° vs 44.92°± 7.35°, P < .001), while IPC significantly increased rotation compared with the portal state at 0° (60.09°± 6.82° vs 51.68°± 10.35°, P = .004). No statistically significant increases were found in mediolateral joint translation after IPC or T-capsulotomy. Similarly, no statistically significant increases were noted in anteroposterior translation after IPC or T-capsulotomy. Complete capsular repair restored near native joint kinematics, with no significant differences in rotation or translation between any complete capsular repair groups and the intact state, regardless of joint position. Conclusion: Universally, across all conditions, complete capsular repair after interportal or T-capsulotomy restored rotational range of motion and joint translation to values observed in the native joint. Clinical Relevance: Where feasible, complete capsular closure should be performed, especially after T-capsulotomy. However, further clinical evaluation is required to determine whether adverse kinematic parameters of an unrepaired capsule are associated with reduced patient-reported outcomes.

Comparison of clinical outcomes of toric intraocular lens, Precizon vs Tecnis: a single center randomized controlled trial

BackgroundTo compare the clinical outcome of Precizon toric intraocular lens (IOL) (Ophtec Inc.) to that of Tecnis toric IOL (Abbott Medical Optics Inc.).MethodsThis randomized comparative study included 40 eyes (Precizon, 20 eyes; Tecnis, 20 eyes) of 40 patients with visually significant cataract and corneal astigmatism who underwent cataract surgery. Changes in uncorrected distant visual acuity (UCDVA), best corrected distant visual acuity (BCDVA), uncorrected intermediate visual acuity (UCIVA), refraction, residual astigmatism, rotation of the IOL axis, and higher order aberrations at 3 months postoperatively were evaluated. Vector analysis was performed using the Alpins method.ResultsBoth groups showed significant reduction in refractive astigmatism after the surgery (Precizon: − 1.06 ± 0.94 Diopter (D) to − 0.31 ± 0.29 D, p = 0.042; Tecnis: − 1.83 ± 1.29 D to − 0.41 ± 0.33 D, p = 0.015). There was no significant (p > 0.05) difference in postoperative UCDVA, BCDVA, or residual astigmatism between the two groups, although a tendency of better UCIVA was observed in the Precizon group. Vector analysis parameters showed no statistically significant difference beween groups(P > 0.05). Significant difference in rotation of toric IOL axis was found between the two groups (Precizon: 1.50° ± 0.84, Tecnis: 2.56° ± 0.68, p = 0.010). Spherical aberration in the Precizon group was significantly (p = 0.005) lower than that in the Tecnis group.ConclusionsThe Precizon toric IOL group had better rotational stability at 3-month postoperatively. Both Precizon toric IOL and Tecnis toric IOL could be effectively used by cataract surgeons to correct preexisting corneal astigmatism through cataract surgery.Trial registrationhttp://clinicaltrials.gov, NCT03085901, retrospectively registered on 21 March 2017.

An observational study of ultrasound to confirm cervical spine segmental positional rotation

ObjectivesVarious studies demonstrate the significance of ultrasound use in undergraduate medical education. Palpatory assessment and diagnosis of the body is fundamental to osteopathic medical education and may be improved by ultrasonographic imaging. A previous study determined that ultrasound is a reliable instrument to assess lumbar spine somatic dysfunctions, yet the use of ultrasound to assess those of the cervical spine has not yet been established. This study investigated the use of ultrasound as an instrument to assess cervical spine vertebral rotation as a component of somatic dysfunctions and to establish the validity of cervical segmental rotatory motion testing. MethodsIn this observational study, two physicians independently confirmed the diagnosis of the most prominent cervical rotational asymmetry. Ultrasound measurements of the left and right articular pillars were obtained by a separate, blinded musculoskeletal radiologist and then compared to palpatory findings. Results: Nineteen of the 41 palpatory findings agreed with ultrasound findings. Results demonstrate no significant difference in rotation of the articular pillars in cases where ultrasound agreed with palpatory findings and in cases where ultrasound did not agree with palpatory findings (p=.099). ConclusionsOur results demonstrate that ultrasound was not an appropriate tool to assess cervical spine segmental rotation compared to palpatory findings. Further studies need to be conducted to improve the assessment of the cervical spine utilizing ultrasound. Differences in cervical spine anatomy and biomechanics as compared to those of the lumbar spine may account for the discrepancy compared to prior studies.

Does a new knee design perform as well as the design it replaces?

ObjectivesThe objective of this study was to compare the early migration characteristics and functional outcome of the Triathlon cemented knee prosthesis with its predecessor, the Duracon cemented knee prosthesis (both Stryker).MethodsA total 60 patients were prospectively randomised and tibial component migration was measured by radiostereometric analysis (RSA) at three months, one year and two years; clinical outcome was measured by the American Knee Society score and the Knee Osteoarthritis and Injury Outcome Score.ResultsThere were no statistically significant differences in rotation or translation around or along the three coordinal axes, or in the maximum total point motion (MTPM) during the two-year follow-up.ConclusionsThe Triathlon cemented knee prosthesis has similar early stability and is likely to perform at least as well as the Duracon cemented knee prosthesis over the longer term.

Fracture fixation with two locking screws versus three non-locking screws

ObjectivesWe aimed to further evaluate the biomechanical characteristics of two locking screws versus three standard bicortical screws in synthetic models of normal and osteoporotic bone.MethodsSynthetic tubular bone models representing normal bone density and osteoporotic bone density were used. Artificial fracture gaps of 1 cm were created in each specimen before fixation with one of two constructs: 1) two locking screws using a five-hole locking compression plate (LCP) plate; or 2) three non-locking screws with a seven-hole LCP plate across each side of the fracture gap. The stiffness, maximum displacement, mode of failure and number of cycles to failure were recorded under progressive cyclic torsional and eccentric axial loading.ResultsLocking plates in normal bone survived 10% fewer cycles to failure during cyclic axial loading, but there was no significant difference in maximum displacement or failure load. Locking plates in osteoporotic bone showed less displacement (p = 0.02), but no significant difference in number of cycles to failure or failure load during cyclic axial loading (p = 0.46 and p = 0.25, respectively). Locking plates in normal bone had lower stiffness and torque during torsion testing (both p = 0.03), but there was no significant difference in rotation (angular displacement) (p = 0.84). Locking plates in osteoporotic bone showed lower torque and rotation (p = 0.008), but there was no significant difference in stiffness during torsion testing (p = 0.69).ConclusionsThe mechanical performance of locking plate constructs, using only two screws, is comparable to three non-locking screw constructs in osteoporotic bone. Normal bone loaded with either an axial or torsional moment showed slightly better performance with the non-locking construct.

Long-Term Outcomes of Fractures of Both Bones of the Forearm

Previous studies identified limited impairment and disability several years after diaphyseal fractures of both the radius and ulna, although the relationship between impairment and disability was inconsistent. This investigation studied skeletally mature and immature patients more than ten years after injury and addressed the hypotheses that (1) objective measurements of impairment correlate with disability, (2) depression and misinterpretation of nociception correlate with disability, and (3) patients injured when skeletally mature or immature have comparable impairment and disability. Seventy-one patients with diaphyseal fractures of the radius and ulna were evaluated at an average of twenty-one years after injury. Twenty-five of the thirty-five patients who were skeletally immature at the time of injury were treated nonoperatively, and thirty-one of the thirty-six skeletally mature patients were treated operatively. Objective evaluation included radiographs, functional assessment, and grip strength. Validated questionnaires were used to measure arm-specific disability (the Disabilities of the Arm, Shoulder and Hand [DASH] score), misinterpretation of pain (Pain Catastrophizing Scale [PCS]), and depression (the validated Dutch form of the Center for Epidemiologic Studies-Depression scale [CES-D]). The average DASH score was 8 points (range, 0 to 54); 97% of patients had excellent or satisfactory results according to the criteria of Anderson et al., and 72% reported no pain. Both the forearm rotation and the wrist flexion/extension arc was 91% of that seen on the uninjured side; grip strength was 94%. There were small but significant differences in rotation (151° versus 169°, p = 0.004) and wrist flexion-extension (123° versus 142°, p = 0.002) compared with the results in the uninjured arm. There was no difference in disability between patients who were skeletally mature or immature at the time of injury. Pain, pain catastrophizing (misinterpretation of nociception), and grip strength were the most important predictors of disability. An average of twenty-one years after sustaining diaphyseal fractures of both the radius and the ulna, patients who were skeletally immature or mature at the time of fracture have comparable disability. Disability correlates better with subjective and psychosocial aspects of illness, such as pain and pain catastrophizing, than with objective measurements of impairment. Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

Long-term Outcomes of Fractures of Both Bones of the Forearm: Level 4 Evidence

Background: Previous studies identified limited impairment and disability several years after diaphyseal fractures of both the radius and ulna, although the relationship between impairment and disability was inconsistent. This investigation studied skeletally mature and immature patients more than ten years after injury and addressed the hypotheses that (1) objective measurements of impairment correlate with disability, (2) depression and misinterpretation of nociception correlate with disability, and (3) patients injured when skeletally mature or immature have comparable impairment and disability. Methods: Seventy-one patients with diaphyseal fractures of the radius and ulna were evaluated at an average of twenty-one years after injury. Twenty-five of the thirty-five patients who were skeletally immature at the time of injury were treated nonoperatively, and thirty-one of the thirty-six skeletally mature patients were treated operatively. Objective evaluation included radiographs, functional assessment, and grip strength. Validated questionnaires were used to measure arm-specific disability (the Disabilities of the Arm, Shoulder and Hand [DASH] score), misinterpretation of pain (Pain Catastrophizing Scale [PCS]), and depression (the validated Dutch form of the Center for Epidemiologic Studies-Depression scale [CES-D]). Results: The average DASH score was 8 points (range, 0 to 54); 97% of patients had excellent or satisfactory results according to the criteria of Anderson et al., and 72% reported no pain. Both the forearm rotation and the wrist flexion/extension arc was 91% of that seen on the uninjured side; grip strength was 94%. There were small but significant differences in rotation (151° versus 169°, p = 0.004) and wrist flexion-extension (123° versus 142°, p = 0.002) compared with the results in the uninjured arm. There was no difference in disability between patients who were skeletally mature or immature at the time of injury. Pain, pain catastrophizing (misinterpretation of nociception), and grip strength were the most important predictors of disability. Conclusions: An average of twenty-one years after sustaining diaphyseal fractures of both the radius and the ulna, patients who were skeletally immature or mature at the time of fracture have comparable disability. Disability correlates better with subjective and psychosocial aspects of illness, such as pain and pain catastrophizing, than with objective measurements of impairment. Level of Evidence: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

The effect of the offset humeral head on the micromovement of pegged glenoid components

In a prospective study between 2000 and 2005, 22 patients with primary osteoarthritis of the shoulder had a total shoulder arthroplasty with a standard five-pegged glenoid component, 12 with non-offset humeral head and ten with offset humeral head components. Over a period of 24 months the relative movement of the glenoid component with respect to the scapula was measured using radiostereometric analysis. Nine glenoids needed reaming for erosion. There was a significant increase in rotation about all three axes with time (p < 0.001), the largest occurring about the longitudinal axis (anteversion-retroversion), with mean values of 3.8 degrees and 1.9 degrees for the non-offset and offset humeral head eroded subgroups, respectively. There was also a significant difference in rotation about the anteversion-retroversion axis (p = 0.01) and the varus-valgus (p < 0.001) z-axis between the two groups. The offset humeral head group reached a plateau at early follow-up with rotation about the z-axis, whereas the mean of the non-offset humeral head group at 24 months was three times greater than that of the offset group accounting for the highly significant difference between them.

Reference markers in computer aided orthopaedic surgery: rotational stability testings and clinical implications

Navigation procedures rely on the stability of the reference arrays (RA) fixed to the bony anatomy. The risk of inadvertent collision and unnoticed movements of the RA may occur, and limb movements might also provocate collisions. Consequently, relevant measurements failures during the navigated procedure might occur and reduce the overall precision of the system. The magnitude of torque to destabilize an RA from its bony-fixation is unknown. The purpose of this study was to determine the ability of standard RA's to resist applied torque. A digital torque application device was developed to allow for precise torque application to the RA system at four cadavers. Clockwise, gradually increasing rotational force was applied to the RA in 1, 2, or 3 Nm, held for 1 s and released, repeated in 10 cycles. One pin fixation systems with 4.0 Schanz pins were used. A second RA was fixed 20 cm proximal to the tested RA. A navigation system was used to measure the relative positions of both RA's during torque application. The rotational differences at torque application were calculated and statistically evaluated. Results revealed averaged 1.0 degrees rotation [range (r), 1.0-1.1 degrees ] with first cycle of 1 Nm torque, the last cycle averaged 1.0 degrees (r, 1.0-1.1 degrees ) with no significant differences in rotation between any of the cycles (p > 0.5). Torque of 2 Nm resulted in 1.8 degrees rotation (r, 1.5-1.8 degrees ) with no significant increases between first and second cycle (p = 0.56), second and third trials (p = 0.35) while fourth cycle averaged 2.0 degrees , with significant increase (p = 0.011). All subsequent cycles resulted in significant increases. Torque of 3 Nm produced 2.9 degrees of rotation for initial cycle (r,2.5-3.3 degrees ), with significant increases with each cycle (p < 005). Torques of > or =2 Nm may cause loosening of the RA, thus may lose its original position relative to the bone. Surgeons using computer aided surgery systems should be aware of possible unrecognized movements of the RA, however, gentle collisions do not appear to cause significant motion or destabilization.

Occlusal Changes Following Posterior Tooth Loss in Adults. Part 2. Clinical Parameters Associated with Movement of Teeth Adjacent to the Site of Posterior Tooth Loss

Much anecdotal evidence is available on tooth positional changes following loss of an adjacent tooth, but only a few studies are available. In Part 1 of this series, supraeruption was assessed and Generalized Linear Models were made to determine the clinical parameters associated with the supraeruptive process. The models demonstrated that clinical parameters were not only associated with the extent of supraeruption, but also with the type of eruption present. This investigation of tooth positional changes adjacent to sites of posterior tooth loss attempts to provide increased understanding of the magnitude, direction, and associated features that may be helpful in decision making and treatment planning in the clinical setting. One hundred patients with an unopposed posterior tooth, with 100 age, sex, and bone level matched controls, were drawn from patients undergoing routine restorative care at Leeds Dental Institute. Study models were scanned, and the extent of eruption, type of eruption of the unopposed tooth, the overbite, overjet, buccal occlusion, and degree of crowding in the dentition, tipping, rotation, and buccal movement of the teeth associated with the edentulous site were recorded. Generalized Linear Models were developed to examine associations between each tooth movement and patient or dental factors. A statistical significance in the degree of tipping of teeth both mesial and distal to the extraction site was detected between the subject and control groups. There was also a significant difference in rotation of the tooth mesial to the site. Four Generalized Linear Models were produced of the types of non-vertical movements found in teeth associated with sites of tooth loss. Teeth adjacent to the site of tooth loss may undergo non-vertical movements. Teeth mesial to the extraction site had a tendency to tip distally. The degree of tipping was increased in upper teeth and in subjects with a cusp-to-cusp buccal occlusion. Rotation of teeth mesial to the extraction site was more prevalent in the lower arch. Tipping of the tooth distal to the extraction site could be extreme and was found to be more prevalent in subjects with a reduced (Code 1) overbite and in the lower arch. Rotation of teeth distal to the extraction site was greater in the upper arch and was also associated with a reduced (Code 1) overbite. It also had an association with rotation of the tooth mesial to the extraction site. Models of non-vertical movement are likely to be of limited value due to overdispersion, indicating a high degree of variability within the model.

Mechanical behavior of the foot and ankle after plantar fascia release in the unstable foot.

The change in position of the bones of the foot was studied in three dimensions after plantar fascia release in intact and destabilized feet. Fifteen fresh-frozen human foot specimens were used. Physiologic loads of 445 newtons were applied axially to simulate standing at ease, and the three-dimensional position of tarsal bones was determined with a magnetic tracking device. The positions were presented in the form of screw axis displacements, quantitating rotation, and axis of rotation orientation. After fasciotomy in the six intact feet, significant differences in rotation were observed at the talotibial and calcaneotalar levels. After fasciotomy in the four unstable feet with three supporting elements sectioned, significant differences in position were observed at the talotibial joint and a significant decrease in arch height was observed. After fasciotomy in the five unstable feet with five supporting elements sectioned, significant differences in rotation were observed at the talotibial joint (mean, 5.5 +/- 1.6 degrees; P = 0.001), calcaneotalar joint (mean, 6.1 +/- 2.1 degrees; P = 0.003), and metatarsotalar level (mean, 9.3 +/- 4.1 degrees; P = 0.007). The average decrease in arch height was 7.4 +/- 4.1 mm (P = 0.015). Displacement of all joints tested occurred after fasciotomy, with rotation about all three axes. These changes in displacement were more pronounced in unstable or destabilized feet. The data suggest that operations involving fasciotomy affect arch stability and should not be performed in patients with evidence of concomitant pes planus deformity, because of the likelihood of further deformation.

Functional enhancement of intrastriatal dopamine-containing grafts by the co-transplantation of sciatic nerve tissue in 6-hydroxydopamine-lesioned rats

Peripheral nerve “bridges” demonstrate the ability to facilitate axonal growth and regenerate adult and fetal central nervous system tissue. The purpose of this study was to determine if co-grafted peripheral nerve tissue could enhance the ability of fetal dopamine (DA) cell transplants to reinnervate host striatum that had been denervated unilaterally. Male Fisher-344 rats were unilaterally lesioned with 6-hydroxydopamine to eliminate the nigrostriatal DA pathway. A total of 31 rats demonstrated a pattern of rotation indicative of a greater than 98% depletion in DA. Rats were kept as nongrafted controls ( n = 6), grafted with sciatic nerve (PN) minces ( n = 6), grafted with fetal ventral mesencephalon (VM; n = 10), or co-grafted with VM and PN minces ( n = 9). All groups were then tested for changes in apomorphine-induced rotational behavior. The PN control group showed no significant differences in rotation when compared to pregrafting levels and to the lesioned nongrafted group. Both the VM-grafted group and the VM-PN co-grafted group showed significant ( P < 0.01, one-way ANOVA) decreases in rotations beginning at 1.5 weeks postgrafting. There was a progressive decrease in rotations up to 12 weeks, the last test point examined. Interestingly, the co-graft group revealed a significantly greater decrease in rotation ( P < 0.05) than the VM group beginning at 5 weeks and continuing out to the 12-week test point. Histological and immunocytochemical studies showed good survival of both PN and VM grafts. The augmented recovery could not be accounted for by increased DA cell survival or host brain DA reinnervation in the co-graft group. Taken together, these findings suggest that PN tissue enhances the ability of fetal VM grafts to reinnervate host brain.

Factors influencing hydrogel toric lens rotation

This study assessed the influence of refractive power variation, corneal topography, and initial wearing time on the rotation of BAUSCH & LOMB® OPTIMA™ Toric lenses. Twenty-three patients wore all combinations of two sphere powers (+3.OOD, −3.OOD), two cylinder powers (−.75D, −2.75D), and three axes (45, 90,180) for 15 minutes each. The results indicate that OPTIMA Toric lenses usually orient closely to the base-down position and that lens rotation is generally independent of lens prescription. No significant difference in rotation was found between with- and-against-the-rule corneas. Little change in rotation was observed over the first 15 minutes of wear, suggesting that shorter trial fitting periods are justified.