Intact Specimen Research Articles

The infra-meniscal fibers of the anterolateral ligament are stronger and stiffer than the supra-meniscal fibers despite similar histological characteristics.

The purpose of the current investigation was to characterize biomechanical differences between the supra- and infra-meniscal sections of the anterolateral ligament (ALL). We hypothesized that the supra-meniscal fibers of the ALL would be stronger and stiffer than the infra-meniscal fiber. Nine cadaveric knee specimens [mean (SD) age = 79 (14.6)years] were dissected to identify the borders of the ALL while maintaining the anatomy of the lateral meniscus. The specimens were randomly assigned to either a supra-meniscal (the ALL below the meniscus was sectioned leaving only the supra-meniscal ALL intact) or an infra-meniscal (the ALL above the meniscus was sectioned leaving only the infra-meniscal attachment intact) group. The specimens were potted into dental cement such that the ALL was pulling laterally on the meniscus when the specimens were secured within an Instron materials testing machine. The specimens were subjected to a tensile failure test at 1mm/s. The load at failure and stiffness were calculated from the force-displacement curves, while peak stress was calculated by normalizing the peak force to the cross-sectional area of the ALL. Furthermore, one intact knee specimen was used to perform a histological analysis on the two ALL sections using Masson's Trichome staining. The infra-meniscal ALL had a significantly (p = 0.03) higher load to failure (195.0 vs. 132.1N) and was significantly (p = 0.03) stiffer than the supra-meniscal fibers (24.8 vs. 12.3N/mm). The relatively similar cross-section areas also resulted in the infra-meniscal sections having a greater peak stress (p = 0.04) (11.1 vs. 5.4MPa). Histological analysis showed relatively consistent fiber orientation with similar organization noted throughout the fibers. The ALL-meniscal construct that includes the infra-meniscal fibers was significantly stronger and stiffer than the construct that includes the supra-meniscal fibers. The infra-meniscal ALL is another important component of the anterolateral complex of the knee, and should be considered when presented with an ACL and/or meniscal injury.

Effects of hip joint transverse plane range of motion with a modeled effusion and capsular tear: A cadaveric study

BackgroundMultiple factors contribute to range of motion of the hip joint in the transverse plane: bony anatomy, hip capsule, corresponding ligaments, articular labrum, ligamentum teres, and negative intra-articular pressure. We hypothesized that violation of the negative pressure of the hip and simulation of an effusion would increase range of motion in the transverse plane in a cadaver model. MethodsTen hip specimens were obtained and dissected with the femur and iliac wing mounted in a custom joint-testing rig in neutral position. Specimens were tested at 0 and at 90° of flexion with 1.5Nm internal and external rotational torque. Three conditions were assessed: (1) intact specimen, (2) an effusion modeled by a 10ml saline infusion, and (3) a capsular tear. FindingsThe modeled effusion decreased rotational range of motion limits in both 0 and 90° of flexion, with a greater effect on the specimens at 0° flexion in external rotation with 4.1° less external rotation (p=0.009). A modeled capsular tear increased rotational motion limits in 0° of flexion in both internal and external rotation and in 90° flexion in internal rotation only (p<0.025). InterpretationAn effusion may decrease the rotation of the hip, and a capsular tear may increase its rotation. This should be considered in hips with traumatic capsular tears or arthroscopic portals.

Effect of Facetectomy on the Three-Dimensional Biomechanical Properties of the Fourth Canine Cervical Functional Spinal Unit: A Cadaveric Study.

Objective To study the biomechanical effect of facetectomy in 10 large breed dogs (>24 kg body weight) on the fourth canine cervical functional spinal unit. Methods Canine cervical spines were freed from all muscles. Spines were mounted on a six-degrees-of-freedom spine testing machine for three-dimensional motion analysis. Data were recorded with an optoelectronic motion analysis system. The range of motion was determined in all three primary motions as well as range of motion of coupled motions on the intact specimen, after unilateral and after bilateral facetectomy. Repeated-measures analysis of variance models were used to assess the changes of the biomechanical properties in the three treatment groups considered. Results Facetectomy increased range of motion of primary motions in all directions. Axial rotation was significantly influenced by facetectomy. Coupled motion was not influenced by facetectomy except for lateral bending with coupled motion axial rotation. The coupling factor (coupled motion/primary motion) decreased after facetectomy. Symmetry of motion was influenced by facetectomy in flexion-extension and axial rotation, but not in lateral bending. Clinical Significance Facet joints play a significant role in the stability of the cervical spine and act to maintain spatial integrity. Therefore, cervical spinal treatments requiring a facetectomy should be carefully planned and if an excessive increase in range of motion is expected, complications should be anticipated and reduced via spinal stabilization.

Numerical Simulation and Experimental Study of Crack Propagation of Polydimethylsiloxane

Polydimethylsiloxane (PDMS) is applied in a wide range of application fields, due to its flexibility, transparent nature, biocompatibility, low cost, etc. Accordingly, it is a very versatile and useful soft polymeric material. However, some applications are severely limited because of its brittleness. Therefore, it is very important to study the fracture characteristics of PDMS. In this study, Neo-Hookean model and Arruda and Boyce model are applied to numerically investigate the crack propagation of three different types with pre-cut cracks. The three types of specimens with pre-cut crack and one type of intact specimen are prepared for tensile test. Meanwhile, high-speed camera is used to record the whole crack propagation during the tensile process. By comparing with the simulation results and experimental results, it is found that Neo-Hookean model and Arruda and Boyce model can satisfactorily be used to simulate the deformation of PDMS. Furthermore, the fitting parameters in the models are very close to the parameters determined experimentally. According to experimental tests, we obtain that the facture energy of PDMS is around 1310 J/m2. The cracks present bluntness before propagation and then quickly propagate to rupture in less than 1 second. In addition, edge crack is the most sensitive type for PDMS among three different cracks.

Hibridinė transanalinė ir laparoskopinė TME po TEM dėl netikėto T2 tiesiosios žarnos vėžio

57 metų moteriai dėl T1 tiesiosios žarnos vėžio buvo atlikta transanalinė endoskopinė mikrochirurginė (TME) operacija. Galutinio patologinio tyrimo duomenimis, buvo konstatuota T2 invazija (1 pav.). Ligonei buvo pasiūlyta totalinė mezorektinė ekscizija (TME). Operacija buvo pradėta pusiau sulenkto lenktinio peilio padėtyje, atliekant dalį TME per išangę (2, 3 pav.). Mobilizuota tiesioji žarna (4 pav.) ir tiesiosios žarnos bigė (5 pav.) buvo užsiūtos rauktinėmis siūlėmis. TME buvo užbaigta laparoskopiškai, sudarant storosios žarnos J rezervuaro jungtį su analiniu kanalu. Tokiu būdu pavyko suformuoti vientisą tiesiosios žarnos preparatą (6 pav.).

A Visualization Method for Corrosion Damage on Aluminum Plates Using an Nd:YAG Pulsed Laser Scanning System.

This paper proposes a non-contact nondestructive evaluation (NDE) technique that uses laser-induced ultrasonic waves to visualize corrosion damage in aluminum alloy plate structures. The non-contact, pulsed-laser ultrasonic measurement system generates ultrasonic waves using a galvanometer-based Q-switched Nd:YAG laser and measures the ultrasonic waves using a piezoelectric (PZT) sensor. During scanning, a wavefield can be acquired by changing the excitation location of the laser point and measuring waves using the PZT sensor. The corrosion damage can be detected in the wavefield snapshots using the scattering characteristics of the waves that encounter corrosion. The structural damage is visualized by calculating the logarithmic values of the root mean square (RMS), with a weighting parameter to compensate for the attenuation caused by geometrical spreading and dispersion of the waves. An intact specimen is used to conduct a comparison with corrosion at different depths and sizes in other specimens. Both sides of the plate are scanned with the same scanning area to observe the effect of the location where corrosion has formed. The results show that the damage can be successfully visualized for almost all cases using the RMS-based functions, whether it formed on the front or back side. Also, the system is confirmed to have distinguished corroded areas at different depths.

The Ferguson Operating Anoscope for Resection of T1 Rectal Cancer

The Ferguson Operating Anoscope (FOA) is a surgical instrument, which can facilitate transanal excision of appropriate rectal tumors within 15 cm of the anal verge. Previous work showed low recurrence (4.3%) for favorable T1 tumors (no lymphovascular invasion, well/moderate differentiation, negative margins). This follow-up study evaluates outcomes in rectal cancer excised with FOA at a tertiary care center. T1 rectal cancer patients were identified in a prospectively maintained database. Tumor pathology and patient characteristics were reviewed. Primary outcomes include tumor recurrence and patient and disease-free survival. Secondary outcomes are quality of excision (intact specimen). Twenty-eight patients had pathologic stage T1 rectal cancer (average 8 ± 2.6 cm from the anal verge). Final path demonstrated 14 per cent to be well differentiated, 82 per cent moderately differentiated, and 93 per cent without angiolymphatic invasion. All specimens removed were intact. One patient had a true local recurrence and underwent a salvage operation 24 months after her index operation. Patient survival was 96.4 per cent (n = one death from primary lung cancer) at median follow-up 64 ± 35 months. With appropriate tumor selection and quality of initial resection, FOA has demonstrated utility in achieving optimal oncologic resection of T1 rectal tumors.

Three-Dimensional Analysis of Fibular Motion After Fixation of Syndesmotic Injuries With a Screw or Suture-Button Construct

Suture-button constructs are an alternative to screw fixation for syndesmotic injuries, and proponents advocate that suture-button constructs may allow physiological motion of the syndesmosis. Recent biomechanical data suggest that fibular instability with syndesmotic injuries is greatest in the sagittal plane, but the design of a suture-button construct, being a rope and 2 retention washers, is most effective along the axis of the rope (in the coronal plane). Some studies report that suture-button constructs are able to constrain fibular motion in the coronal plane, but the ability of a tightrope to constrain sagittal fibular motion is unknown. The purpose of this study was to assess fibular motion in response to an external rotation stress test in a syndesmotic injury model after fixation with a screw or suture-button constructs. Eleven fresh-frozen cadaver whole legs with intact tibia-fibula articulations were secured to a custom fixture. Fibular motion (coronal, sagittal, and rotational planes) in response to a 6.5-Nm external rotation moment applied to the foot was recorded with fluoroscopy and a high-resolution motion capture system. Measures were taken for the following syndesmotic conditions: intact, complete lateral injury, complete lateral and deltoid injury, repair with a tetracortical 4.0-mm screw, and repair with a suture button construct (Tightrope; Arthrex, Naples, FL) aimed from the lateral fibula to the anterior medial malleolus. The suture-button construct allowed significantly more sagittal plane motion than the syndesmotic screw. Measurements acquired with mortise imaging did not detect differences between the intact, lateral injury, and 2 repair conditions. External rotation of the fibula was significantly increased in both injury conditions and was not restored to intact levels with the screw or the suture-button construct. A single suture-button placed from the lateral fibula to the anterior medial malleolus was unable to replicate the motion observed in the intact specimen when subjected to an external rotation stress test and allowed significantly more posterior motion of the fibula than when fixed with a screw in simulated highly unstable injuries. Fixation of a syndesmotic injury with a single suture-button construct did not restore physiological fibular motion, which may have implications for postoperative care and clinical outcomes.

Dynamic Strength and Fracturing Behavior of Single-Flawed Prismatic Marble Specimens Under Impact Loading with a Split-Hopkinson Pressure Bar

Dynamic impact tests are performed on prismatic marble specimens containing a single flaw using a modified split-Hopkinson pressure bar device. The effects of pre-existing flaws with different flaw angles and lengths on the dynamic mechanical properties are analyzed. The results demonstrate that the dynamic strength of marble is influenced by the flaw geometry. The dynamic fracturing process of flawed specimens is monitored and characterized with the aid of a high-speed camera. Cracking of marble specimens with a single pre-existing flaw under impact loading is analyzed based on experimental investigations. Cracking involves two major stages: formation of white patches and development of macrocracks. Six typical crack types are identified on the basis of their trajectories and initiation mechanisms. The presence of an artificial flaw may change the failure mode of marble from splitting-dominated for an intact specimen to shear-dominated for a flawed specimen under dynamic loading. Nevertheless, the geometry of the flaws appears to have a slight influence on the failure modes of flawed specimens under impact loading.

Anchorage behaviour of reinforced specimens containing a single fissure under uniaxial loading: a particle mechanics approach

Particle flow code (PFC2D) software was adopted to investigate the anchorage behaviour and the characteristics of crack initiation, propagation and coalescence of reinforced specimens containing a single fissure (RSCSF). The microscopic parameters of the specimens in the numerical simulation were first validated by experimental outcomes of intact specimens, while the microscopic parameters of the rock bolts were validated based on the results of the RSCSF tests. Then, the mechanical parameters as well as the failure modes in the physical experiments were compared with those derived by the numerical simulation; the results showed good agreement between the simulated macroscopic mechanical properties and failure modes and those obtained in the laboratory experiments. The peak strength, number of cracks and the failure mode varied considerably as the anchorage angle α and fissure angle β increased. Three types of stress–strain curves, types I to III, were obtained from the RSCSF. Shear cracks were observed for all three categories of curves, but the tensile cracks were dominant. The number of cracks and the rate of bond failures decreased as the curve changed from type II to type I to type III. RSCSF failure can be classified into three failure modes: (1) tip crack propagation mode, (2) midpoint crack propagation mode and (3) rock bolt crack propagation mode. These failure modes are primarily differentiated by relations between α and β, and the ratio UCSS/UCSI between the uniaxial compressive strength (UCS, σ max) of the RSCSF (UCSS) and the uniaxial compressive strength of the intact specimen (UCSI).

Biomechanical Comparison of Acute Hill-Sachs Reduction and Remplissage to Treat Complex Anterior Instability

Objectives:Acute Hill-Sachs (HS) reduction represents a potential alternative method to remplissage for the treatment of an engaging HS lesion. The purpose of this study is to biomechanically compare the stabilizing effects of an acute HS reduction technique and remplissage in a complex instability model.Methods:This was a comparative cadaveric study of 6 shoulders. For the acute HS lesion, a unique model was used to create a 30% defect, compressing the subchondral bone while preserving the articular surface in a more anatomic fashion. In addition, a 15% glenoid defect was made in all specimens. The HS lesion was reduced through a lateral cortical window with a bone tamp, and the subchondral void was filled with Quickset (Arthrex) bone cement to prevent plastic deformation. Five scenarios were tested; intact specimen, bipolar lesion, Bankart repair, remplissage with Bankart repair and HS reduction technique with Bankart repair. Translation, kinematics and dislocation events were recorded.Results:For all 6 specimens no dislocations occurred after either remplissage or the reduction technique. At 90 degrees of abduction and external rotation (ABER), anterior-inferior translation was 11.1 mm (SD 0.9) for the bipolar lesion. This was significantly reduced following both remplissage (5.1±0.7 mm; p<0.001) and HS reduction (4.4 ±0.3 mm; p<0.001). For anterior-inferior translation there was no significant difference in translation between the reduction technique and remplissage (p=0.91). At 90 degrees of ABER, the intact specimens average joint stiffness was 7.0 ±1.0N/mm, which was not significantly different from the remplissage (7.8±0.9 N/mm; p=0.9) and reduction technique (9.1±0.6 N/mm; p=0.50). Compared with an isolated Bankart repair, the average external rotation loss after also performing a remplissage procedure was 4.3 ±3.5 deg (p=0.65), while average ER loss following HS reduction was 1.1 ±3.3 deg (p=0.99). There was no significant difference in external rotation between remplissage and the reduction technique (p=0.83).Conclusion:Similar joint stability was conferred following both procedures, though remplissage had 3.2-degree loss of ER in comparison. While not statistically significant, even slight ER loss may be clinically detrimental in overhead athletes. Overall, the acute reduction technique is a more anatomic alternative to the remplissage procedure with similar ability to prevent dislocation in a biomechanical model, making it a viable treatment option for engaging Hill-Sachs lesions.

Biomechanical Comparison of a Hill-Sachs Reduction Technique and Remplissage: The Potential Benefits of Anatomic Reconstruction

Biomechanical Comparison of a Hill-Sachs Reduction Technique and Remplissage: The Potential Benefits of Anatomic Reconstruction

Modeling the Human Tibiofemoral Joint Using Ex Vivo Determined Compliance Matrices.

Several approaches have been used to devise a model of the human tibiofemoral joint for embedment in lower limb musculoskeletal models. However, no study has considered the use of cadaveric 6 × 6 compliance (or stiffness) matrices to model the tibiofemoral joint under normal or pathological conditions. The aim of this paper is to present a method to determine the compliance matrix of an ex vivo tibiofemoral joint for any given equilibrium pose. Experiments were carried out on a single ex vivo knee, first intact and, then, with the anterior cruciate ligament (ACL) transected. Controlled linear and angular displacements were imposed in single degree-of-freedom (DoF) tests to the specimen, and the resulting forces and moments were measured using an instrumented robotic arm. This was done starting from seven equilibrium poses characterized by the following flexion angles: 0 deg, 15 deg, 30 deg, 45 deg, 60 deg, 75 deg, and 90 deg. A compliance matrix for each of the selected equilibrium poses and for both the intact and ACL-deficient specimen was calculated. The matrix, embedding the experimental load-displacement relationship of the examined DoFs, was calculated using a linear least squares inversion based on a QR decomposition, assuming symmetric and positive-defined matrices. Single compliance matrix terms were in agreement with the literature. Results showed an overall increase of the compliance matrix terms due to the ACL transection (2.6 ratio for rotational terms at full extension) confirming its role in the joint stabilization. Validation experiments were carried out by performing a Lachman test (the tibia is pulled forward) under load control on both the intact and ACL-deficient knee and assessing the difference (error) between measured linear and angular displacements and those estimated using the appropriate compliance matrix. This error increased nonlinearly with respect to the values of the load. In particular, when an incremental posterior-anterior force up to 6 N was applied to the tibia of the intact specimen, the errors on the estimated linear and angular displacements were up to 0.6 mm and 1.5 deg, while for a force up to 18 N, the errors were 1.5 mm and 10.5 deg, respectively. In conclusion, the method used in this study may be a viable alternative to characterize the tibiofemoral load-dependent behavior in several applications.

Sagittal Plane Correction Using Lateral Transpsoas Approach: Effect of Cage Angulation and Surgical Technique on Segmental Lordosis

Introduction Lordotic cage insertion through lateral transpsoas approach is being used increasingly for restoration of sagittal alignment. However, the degree of correction achieved by varying cage angle as well as ALL release and posterior element resection is not well defined. The objective of this study is to determine the degree of segmental correction which could be achieved through lateral transpsoas approach by varying cage angle as well as adding anterior longitudinal ligament (ALL) release and posterior element resection. Material and Methods Thirteen human cadaveric lumbar motion segments between L1 and L5 were dissected into single motion segments. Segmental angles and disk heights were measured under both 50N and 500N loads under the following conditions: Intact specimen, discectomy (collapsed disk simulation), insertion of parallel cage, 10° cage, 30° cage with ALL release, 30° cage with ALL release and spinous process (SP) resection, 30° cage with ALL release, SP resection, facetectomy and compression with pedicle screws. Results Segmental lordosis was not increased by with either parallel or 10° cages as compared with intact disks, and contributed small amounts of lordosis when compared with the collapsed disk condition. Placement of 30° cages with ALL release increased segmental lordosis by 10.5°. Adding SP resection increased lordosis to 12.39°. Facetectomy and compression with pedicle screws further increased gains in lordosis to 26.4° in the 50N group and 25.8° in the 500N group. Neither group experienced a decrease in either anterior or posterior disk height. Conclusion Insertion of parallel or 10° cage has little effect on lordosis. 30° cage insertion and ALL release resulted in an increase of lordosis by ~10.5°. The addition of SP resection and facetectomy allowed increases in correction of up to 26.4°. No interventions resulted in decrease in either anterior or posterior disk height suggesting gains were achieved without causing foraminal stenosis.

Myofiber Architecture of the Human Atria as Revealed by Submillimeter Diffusion Tensor Imaging.

Accurate knowledge of the human atrial fibrous structure is paramount in understanding the mechanisms of atrial electric function in health and disease. Thus far, such knowledge has been acquired from destructive sectioning, and there is a paucity of data about atrial fiber architecture variability in the human population. In this study, we have developed a customized 3-dimensional diffusion tensor magnetic resonance imaging sequence on a clinical scanner that makes it possible to image an entire intact human heart specimen ex vivo at submillimeter resolution. The data from 8 human atrial specimens obtained with this technique present complete maps of the fibrous organization of the human atria. The findings demonstrate that the main features of atrial anatomy are mostly preserved across subjects although the exact location and orientation of atrial bundles vary. Using the full tractography data, we were able to cluster, visualize, and characterize the distinct major bundles in the human atria. Furthermore, quantitative characterization of the fiber angles across the atrial wall revealed that the transmural fiber angle distribution is heterogeneous throughout different regions of the atria. The application of submillimeter diffusion tensor magnetic resonance imaging provides an unprecedented level of information on both human atrial structure, as well as its intersubject variability. The high resolution and fidelity of this data could enhance our understanding of structural contributions to atrial rhythm and pump disorders and lead to improvements in their targeted treatment.

Comparison and discussion on fragmentation behavior of soft rock in multi-indentation tests by a single TBM disc cutter

This paper is to investigate the mechanical responses and failure characteristics of soft rock in multi-indentation tests by a single TBM constant cross section (CCS) disc cutter. Different pre-set penetration depths and totally three cycles of indentation processes were employed in the repeated indentation tests conducted on the cubic cement mortar specimens. The load-penetration depth curve, penetration load, peak-load penetration depth, rock breakage work and compacted zone depth for the three indentation processes were analyzed. The strength and deformation properties and failure behavior of soft rock under different indentation conditions were revealed. The rock breakage behavior after several indentation processes still presents brittle failure characteristic with small pre-set penetration depths, but the specimens with large pre-set penetration depths appear obvious plastic failure mode. Approximately equal leap loads are obtained from both the intact specimen in direct indentation failure test and the weakened specimens after several indentation processes with different pre-set penetration depths, but the peak-load penetration depths for specimens with different pre-set penetration depths are varying. Curves of the cumulative penetration depth and cumulative rock breakage work both reach the corresponding peak values for one certain pre-set penetration depth. Along with this most unfavourable pre-set penetration depth, rock breakage efficiency is the lowest and energy consumption is the highest.

Abstract P4-03-05: Wide-field optical coherence tomography (WF-OCT) for near real-time, point-of-care assessment of margin status in breast-conserving surgery specimens: Results of a feasibility study at a high-volume single-centre

Abstract Wide-Field Optical Coherence Tomography (WF-OCT) is a non-destructive, non-contact light imaging modality capable of label-free visualization of the internal microscopic architecture of breast tissue specimens. Its unique combination of high-resolution imaging in near real-time with tissue penetration depths approaching 2-mm makes it a promising imaging modality for obtaining detailed surgical margin status in breast-conserving surgery (BCS) specimens. A prototype WF-OCT imaging platform developed by Perimeter Medical Imaging, Inc. (Toronto, Canada) has permitted fully-automated, dynamically-focused visualization of margin widths around the intact surfaces of freshly excised BCS specimens. Herein are reported the results of a feasibility study at a high-volume single-centre evaluating the routine use of WF-OCT for sampling of surgical margin status in BCS specimens at the point-of-care. Methods: Women with biopsy confirmed breast cancer and scheduled for primary BCS were recruited at Princess Margaret Cancer Centre (Toronto, Canada). Standard medical care was not altered. Freshly excised BCS specimens including all lumpectomy samples were imaged by WF-OCT immediately prior to standard histological processing. The system acquired dynamically-focused, hemispherical coverage over two contra-lateral surfaces of the intact BCS specimen within the time constraints of the cold ischemic time window. High-resolution (10 μm) images of the tissue surface down to a 1 to 2-mm depth were obtained. Blinded assessments were performed on image data sets by two clinical readers (surgeon and radiologist) trained on a validated and unrelated data set correlating OCT images with histology slides. The readers were first asked to independently assess margin status using only blinded pre- and intra-operative knowledge (without OCT). Upon completion, the readers were provided OCT images of all scanned surface and similarly asked to assess the margin status with the additional OCT information. These assessments were subsequently evaluated by a breast pathologist comparing the OCT images and corresponding histopathology sections. The added utility of WF-OCT imaging information for margin prediction was studied. Results: [Pending study completion in August 2015]. Through accurate correlation with the histopathologic gold standard, OCT demonstrated capability to differentiate tissue microstructures, including: distinctive patterns for adipose tissue, fibrous stroma, breast lobules and ducts, cysts and microcysts, as well as in-situ and invasive carcinomas. Implications: The fully-automated WF-OCT imaging platform can integrate conveniently into standard pathological processing workflows to provide comprehensive sampling of surgical margin status in BCS specimens at the point-of-care. Clinical readers from surgical and radiological backgrounds can be trained to competently interpret WF-OCT images of BCS specimens for accurate prediction margin status. The implementation of WF-OCT at the point-of-care for routine surgical margin assessments will be further explored in future clinical trials. Citation Format: Valic MS, Leong WL, Done SJ, Wilson BC, Kulkarni S, McCready DR, Niu CJ, Atachia Y, Munro EA, Rempel D. Wide-field optical coherence tomography (WF-OCT) for near real-time, point-of-care assessment of margin status in breast-conserving surgery specimens: Results of a feasibility study at a high-volume single-centre. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-03-05.

Avoiding Morcellation of Laparoscopic Hysterectomy Specimens with Preoperative Measurement of Uterine Volume

Abstract Background: Hysterectomy is the second most common surgery among women, with ∼600,000 performed each year in the United States. Objective: The aim of this research was to identify preoperative factors associated with the ability to remove an intact uterine specimen transvaginally and avoid morcellation during laparoscopic hysterectomy. Materials and Methods: Patients were identified who underwent robotic-assisted total laparoscopic hysterectomy from January 9, 2008, to November 15, 2012. Charts were reviewed retrospectively for demographics. Preoperative uterine dimensions were used to calculate uterine volume. Subjects without preoperative uterine dimensions based on imaging were excluded. Demographics, indication for hysterectomy, need for uterine morcellation, histology, and actual uterine weight were noted. Statistical analysis was performed, using recursive partitioning and logistical regression analyses. Results: Four hundred and thirty-six patients were identified, with 136 excluded becaus...

Safety of Manual Morcellation After Vaginal or Laparoscopic-assisted Vaginal Hysterectomy

Study ObjectiveTo determine the safety of manual vaginal morcellation by evaluating the rates of incidental uterine malignancy and manual vaginal morcellation after vaginal or laparoscopic-assisted vaginal hysterectomy. DesignRetrospective analysis (Canadian Task Force classification II-2). SettingUniversity of Texas Southwestern Medical Center, Dallas, TX. PatientsWomen (n = 1,629) undergoing vaginal or laparoscopic-assisted vaginal hysterectomy. InterventionsVaginal hysterectomy (n = 1,091) or laparoscopic-assisted vaginal hysterectomy (n = 538) with and without scalpel morcellation. Measurements and Main ResultsThe number of uterine malignancies, rate of vaginal morcellation, surgical indications, pathology diagnoses, and uterine weights were evaluated. Chi-square analysis was used to compare categoric data, and analysis of variance was used to compare uterine weights. There were no cases of leiomyosarcomas. There were 2 other sarcomas, 4 smooth muscle tumors of uncertain malignant potential, and 8 endometrial adenocarcinomas. The vaginal morcellation rate was 19.4%, but no malignancy was morcellated. Myomas were more common preoperatively and histologically in morcellated specimens. Mean (± standard deviation) uterine weights for morcellated versus nonmorcellated laparoscopic-assisted vaginal hysterectomy specimens were 285.5 ± 159.3 versus 140.1 ± 83.6 g (p < .001), respectively, and 199.9 ± 92.8 versus 111.9 ± 61.4 (p < .001), respectively, for vaginal hysterectomy. ConclusionVaginal manual morcellation is safe with a low risk of incidental malignancy. Variables that influence the decision for the vaginal approach may also affect malignancy risk and morcellation decisions. Thus, all patients undergoing vaginal or laparoscopic-assisted vaginal hysterectomy should be counseled regarding incidental malignancy, risk of morcellation, and alternatives for intact specimen removal.

The effect of coracoacromial ligament excision and acromioplasty on the amount of rotator cuff force production necessary to restore intact glenohumeral biomechanics

Coracoacromial ligament (CAL) excision and acromioplasty increase superior and anterosuperior glenohumeral translation. It is unknown how much of an increase in rotator cuff force production is required to re-establish intact glenohumeral biomechanics after these surgical procedures. We hypothesized that, after CAL excision and acromioplasty, an increase in rotator cuff force production would not be necessary to reproduce the anterosuperior and superior translations of the intact specimens. Nine cadaveric shoulders were subjected to loading in the superior and anterosuperior directions in the intact state after CAL excision, acromioplasty, and recording of the translations. The rotator cuff force was then increased to normalize glenohumeral biomechanics. After CAL excision at 150 and 200 N of loading, an increase in the rotator cuff force by 25% decreased anterosuperior translation to the point where there was no significant difference from the intact specimen's translation. After acromioplasty (and CAL excision) at 150 and 200 N, an increase in the rotator cuff force of 25% and 30%, respectively, decreased superior translation to the point where there was no significant difference from the intact specimen's translation. At 150 to 200 N of loading, CAL excision and acromioplasty increase the rotator cuff force required to maintain normal glenohumeral biomechanics by 25% to 30%. After a subacromial decompression, the rotator cuff has an increased force production requirement to maintain baseline glenohumeral mechanics. Under many circumstances, in vivo force requirements may be even greater after surgical attenuation of the coracoacromial arch. Basic Science Study; Biomechanics.