Phillip Spiegel Orthopaedic Research Laboratory

Tampa, FL, United States

Phillip Spiegel Orthopaedic Research Laboratory

Tampa, FL, United States

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Hee C.K.,BioMimetic Therapeutics | Dines J.S.,Hospital for Special Surgery | Dines D.M.,Hospital for Special Surgery | Roden C.M.,BioMimetic Therapeutics | And 6 more authors.
American Journal of Sports Medicine | Year: 2011

Background: Rotator cuff tears are a common source of shoulder pain. High rates (20%-94%) of structural failure of the repair have been attributed to multiple factors, including poor repair tissue quality and tendon-to-bone integration. Biologic augmentation using growth factors has potential to promote tendon-to-bone integration, improving the function and long-term success of the repair. One such growth factor is platelet-derived growth factor-BB (PDGF-BB), which has been shown to improve healing in tendon and bone repair models. Hypothesis: Recombinant human PDGF-BB (rhPDGF-BB) combined with a highly porous type I bovine collagen matrix will improve the biomechanical function and morphologic appearance of the repair in a dose-dependent manner, relative to a suture-only control, after 12 weeks in an acute ovine model of rotator cuff repair. Study Design: Controlled laboratory study. Methods: An interpositional graft consisting of rhPDGF-BB and a type I collagen matrix was implanted in an ovine model of rotator cuff repair. Biomechanical and histologic analyses were performed to determine the functional and anatomic characteristics of the repair after 12 weeks. Results: A significant increase in the ultimate load to failure was observed in repairs treated with 75 mg (1490.5 6 224.5 N, P = .029) or 150 mg (1486.6 6 229.0 N, P = .029) of rhPDGF-BB, relative to suture-only controls (910.4 6 156.1 N) and the 500-mg rhPDGF-BB group (677.8 6 105.9 N). The 75-mg and 150-mg rhPDGF-BB groups also exhibited increased tendon-to-bone interdigitation histologically. No differences in inflammation or cellularity were observed among treatments. Conclusion: This study demonstrated that an interpositional graft consisting of rhPDGF-BB (75 or 150 mg) and a type I collagen matrix was able to improve the biomechanical strength and anatomic appearance in an ovine model of rotator cuff repair compared to a suture-only control and the 500-mg rhPDGF-BB group. Clinical Relevance: Recombinant human PDGF-BB combined with a type I collagen matrix has potential to be used to augment surgical repair of rotator cuff tears, thereby improving clinical success. © 2011 The Author(s).


Santoni B.G.,Phillip Spiegel Orthopaedic Research Laboratory | Ehrhart N.,Colorado State University | Betancourt-Benitez R.,University of Rochester | Beck C.A.,University of Rochester | Schwarz E.M.,University of Rochester
Clinical Orthopaedics and Related Research | Year: 2012

Background: Allograft integration in segmental osseous defects is unpredictable. Imaging techniques have not been applied to investigate angiogenesis and bone formation during allograft healing in a large-animal model. Questions/purposes: We used dynamic contrast-enhanced (DCE)-MRI and cone beam (CB)-CT to quantify vascularity and bone volume in a canine femoral allograft model and determined their relationship with biomechanical testing and histomorphometry. Methods: Femoral ostectomy was performed in three dogs and reconstructed with a 5-cm allograft and compression plate. At 0.5, 3, and 6 months, we performed DCE-MRI to quantify vascular permeability (Ktrans) and perfused fraction and CB-CT to quantify bone volume. We also performed posteuthanasia torsional testing and dynamic histomorphometry of the grafted and nonoperated femurs. Results: DCE-MRI confirmed the avascular nature of allograft healing (perfused fraction, 2.08%-3.25%). CB-CT demonstrated new bone formation at 3 months (26.2, 3.7, and 2.2 cm 3) at the graft-host junctions, which remodeled down at 6 months (14.0, 2.2, and 2.0 cm 3). The increased bone volume in one subject was confirmed with elevated Ktrans (0.22) at 3 months. CB-CT-identified remodeled bone at 6 months was corroborated by histomorphometry. Allografted femurs recovered only 40% of their strength at 6 months. Conclusions: CB-CT and DCE-MRI can discriminate differences in angiogenesis and bone formation in the canine allograft model, which has potential to detect a small (32%) drug or device effect on biomechanical healing with only five animals per group. Clinical Relevance: These radiographic tools may have the potential to assess adjuvant effects on vascular invasion and new bone formation after segmental allograft transplantation. © 2012 The Association of Bone and Joint Surgeons®.


Marulanda G.A.,Florida Orthopedic Institute | Nayak A.,Phillip Spiegel Orthopaedic Research Laboratory | Murtagh R.,University of Florida | Santoni B.G.,Phillip Spiegel Orthopaedic Research Laboratory | And 2 more authors.
Journal of Spinal Disorders and Techniques | Year: 2014

Study Design: Cadaveric Biomechanical and Radiographic Analysis. Objective: The Purpose of this study was to quantify the changes in intervertebral height and lateral and central recess areas afforded by lateral interbody fusion cages with 2 supplemental forms of internal fixation in cadaveric specimens. BACKGROUND DATA: When conservative treatment for symptomatic lumbar stenosis fails, traditional intervention has been direct posterior decompression. The minimally invasive, lateral transpsoas approach may be a viable alternative to direct decompression by providing restoration of the foraminal and intervertebral dimensions, yet few reports have examined the anatomic and radiographic changes that occur using this technique. Methods: Computed tomography (CT) scans were taken of 18 intact lumbar (L1-S1) cadaveric specimens under a 400 N preload. Intervertebral height, foraminal areas, and canal area were measured at L3-L4 and L4-L5. Thereafter, the cadaveric specimens were instrumented with lateral cages placed in the central or posterior third of the disk space at L3-L4 and L4-L5 and either (1) lateral plate (n=9) or (2) bilateral posterior pedicle screw fixation (n=9). All constructs were again subjected to a 400 N preload, postinstrumentation CT scans were taken, and changes in intervertebral height and lateral and central recess areas were calculated. Results: There was no effect of cage placement on any radiographic metric of indirect decompression for either fusion construct. In the lateral plate and pedicle screw groups, respectively, significant increases in average posterior disk height (30.9%, 60.1%), average right (35.3%, 61.5%) and left foraminal area (48.3%, 57.8%), and average canal area (32.3%, 33.3%) were observed. Pedicle screw instrumentation afforded a significantly greater increase in average posterior disk height and foraminal area compared with the lateral plate group, though there was no difference in the average increase in canal area afforded by either form of fixation. Conclusions: The radiographic results reported here using a cadaveric model add validity to the underlying rationale described for the minimally invasive lateral approach technique. Increases in disk height, foraminal and canal areas were not dependent on cage positioning within the disk space. As intraoperative placement of a cage in the central portion of the disk is an easier and safer technique, our results suggest that central placement may be preferable in a clinical setting. © 2014 by Lippincott Williams & Wilkins.


Cuff D.,Suncoast Orthopaedic Surgery | Levy J.C.,Orthopaedic Institute at Holy Cross | Gutierrez S.,Phillip Spiegel Orthopaedic Research Laboratory | Frankle M.A.,Florida Orthopaedic Institute
Journal of Shoulder and Elbow Surgery | Year: 2011

Hypothesis/background: Patients who are treated with reverse shoulder arthroplasty in the setting of proximal humeral bone loss present a technical challenge for humeral component fixation. The purpose of this study was to determine the effect of proximal humeral bone loss on fixation of reverse shoulder humeral implants. Materials and methods: Three reverse humeral designs (two modular and one monobloc) were cemented into twenty-four Sawbones humeri prepared to simulate intact and proximal humeral bone loss. Torque was applied to the humerus for 1,000 cycles in increments of 2.5 N-m to 25 N-m. Rotational micromotion of the implant was measured. Results: There was a significant decrease in rotational micromotion in the intact constructs when compared with the bone loss constructs (we found P < .01 when looking at torsion levels of 5 to 17.5 N-m). In the intact humerus, 10 of 12 implant constructs survived testing. The 2 that failed were modular implants. In the bone loss setting, 7 of 12 implant constructs survived testing. The 5 that failed were also modular implants. Conclusions: This is the first investigation on humeral component fixation in reverse shoulder arthroplasty. The proximal humerus adds stability to the fixation of a cemented humeral implant. Modular components in the presence of proximal humeral bone loss may be at increased risk of mechanical failure. Conversely, non-modular cemented humeral components can withstand greater loads before failure. © 2011.


Virani N.A.,Phillip Spiegel Orthopaedic Research Laboratory | Cabezas A.,Phillip Spiegel Orthopaedic Research Laboratory | Gutierrez S.,Phillip Spiegel Orthopaedic Research Laboratory | Santoni B.G.,Phillip Spiegel Orthopaedic Research Laboratory | And 2 more authors.
Journal of Shoulder and Elbow Surgery | Year: 2013

Background: Modifications in reverse shoulder arthroplasty (RSA) have been made with the intent of maximizing motion, although there is little objective evidence outlining their benefit. This study investigated the RSA component combinations that impart the greatest effect on impingement-free glenohumeral motion. Methods: A previously validated virtual shoulder model was implanted with RSA components that varied by humeral implant type (inset/onset), glenosphere diameter (30, 36, and 42 mm), glenosphere placement (inferior/neutral), glenosphere center-of-rotation offset (0, 5, and 10 mm), humeral neck-shaft angle (130° and 150°), and humeral offset (zero, five, and ten mm). Motion was simulated in all technique combinations until the point of impingement in abduction, flexion/extension (F/E), and internal/external rotation (IR/ER). Regression analysis was used to rank combinations based on motion. Results: Of 216 possible study combinations, 126 constructs (58%) demonstrated no arm-at-side impingement and were included for analysis. Models with the largest motion in abduction, F/E, and IR/ER, respectively, were inset-42-inferior-10-150-zero (107°), inset-36-inferior-10-130-five (146°), and inset-42-inferior-10-130-ten (121°). Humeral neck-shaft angle, glenosphere center-of-rotation offset, glenosphere placement, and glenosphere diameter had a significant effect on motion in all planes tested. Of these variables, humeral neck-shaft angle was most predictive of a change in abduction and F/E motion, whereas glenosphere placement was most predictive of a change in IR/ER motion. Conclusion: Higher glenosphere center-of-rotation offsets led to an increase in motion in all planes. To maximize motion in abduction, a valgus humeral component should be selected; to maximize F/E, a varus humeral component should be selected; and, to maximize IR/ER, the glenosphere should be placed inferiorly. © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees.


Pervaiz K.,Florida Orthopaedic Institute | Cabezas A.,Phillip Spiegel Orthopaedic Research Laboratory | Downes K.,University of South Florida | Santoni B.G.,Phillip Spiegel Orthopaedic Research Laboratory | Frankle M.A.,Florida Orthopaedic Institute
Journal of Shoulder and Elbow Surgery | Year: 2013

Background: Patients with osteoarthritis undergoing shoulder arthroplasty may suffer from osteoporosis. The purpose of this study was to determine whether computed tomography (CT)-derived Hounsfield unit (HU) measurements correlate with bone mineral density (BMD) and whether these data could predict implant size and fixation choice. Materials and methods: The study analyzed preoperative dual energy x-ray absorptiometry and shoulder CT scans for 230 patients who underwent total shoulder arthroplasty. Hip BMD and T scores and HU attenuation in the humerus were correlated. HU cutoff values were developed to aid in differentiating patients whose BMD values were within normal reference ranges from patients with osteopenia or osteoporosis. Risk factors associated with low BMD were correlated, and the effect of BMD on humeral stem size, and fixation method was investigated. Results: Significant correlations between HU and hip BMD and T score were identified (P < .001). HU value ranges were identified that may alert the surgeon of metabolic bone disease. Significant correlation (P < 0.05) was found between low BMD and certain osteoporosis risk factors. Age at time of surgery was a predictor of cemented stem fixation (P = .024). Patients with a lower BMD were statistically more likely to receive a larger-diameter humeral stem (P = .016). Conclusions: Orthopedic surgeons may be able to use data obtained from shoulder CT scans to predict the need for larger stem size or cement fixation during shoulder arthroplasty. In combination with the risk factor profile, these data may be useful in predicting the need for an osteoporosis workup and treatment. © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees.


Hussey M.M.,Florida Orthopaedic Institute | Steen B.M.,Florida Orthopaedic Institute | Cusick M.C.,Florida Orthopaedic Institute | Cox J.L.,Phillip Spiegel Orthopaedic Research Laboratory | And 5 more authors.
Journal of Shoulder and Elbow Surgery | Year: 2015

Background: Despite the success of total shoulder arthroplasty (TSA), concerns remain about the longevity of the implant, in particular, glenoid component survivorship. The purpose of this study was to determine whether preoperative glenoid wear patterns affect clinical outcomes and value in patients undergoing TSA. Methods: A comparative cohort study was conducted of 309 patients with a total of 344 TSA procedures, performed for primary glenohumeral osteoarthritis. Computed tomography scans were obtained in all patients, with preoperative glenoid wear pattern characterized as either concentric (n=196; follow-up time, 49.2months) or eccentric (n=148; follow-up time, 52.3months) according to a modified Levine classification. A clinical, radiographic, and economic assessment was performed between the 2 wear patterns. Results: There was no significant difference in American Shoulder and Elbow Surgeons (ASES) score in the concentric group (80.8±20.8) compared with the eccentric group (77.6±21.2) at final follow-up (. P=.159). Range of motion and final visual analog scale for pain score were similar between the 2 groups. Radiographic evidence of gross glenoid loosening was significantly lower in the concentric group [11 of 195 (5.6%)] compared with the eccentric group [18 of 147 (12.2%)] (. P=.030). Revision rates were similar between the concentric group [4 of 195 (2.0%)] and the eccentric group [3 of 147 (2.0%)]. A value assessment also showed no significant difference between the concentric and eccentric groups [concentric 26.1 vs. eccentric 25.5 (δASES score/$10,000 hospital cost) (. P=.479)]. Conclusions: Similar clinical results and value can be expected with both concentric and eccentric glenoid wear patterns in TSA. Concerns arise, however, as the eccentric group demonstrated a more than 2-fold increased rate of glenoid component loosening compared with the concentric group. © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees.


Simon P.,Phillip Spiegel Orthopaedic Research Laboratory | Gupta A.,Florida Orthopaedic Institute | Pappou I.,Florida Orthopaedic Institute | Hussey M.M.,Florida Orthopaedic Institute | And 3 more authors.
Journal of Shoulder and Elbow Surgery | Year: 2015

Background: Glenoid component loosening in total shoulder arthroplasty may be prevented by component placement on a congruent and adequate bony surface. Glenoid subchondral bone density (SBD) variability may be correlated with this concept. This study analyzed the 3-dimensional distribution of glenoid SBD in total shoulder arthroplasty patients with osteoarthritis. Materials and methods: Three-dimensional computed tomography osteoabsorptiometry (CT-OAM) was performed in 42 men (21 with eccentric and 21 with concentric wear patterns) with glenohumeral arthritis. Glenoid SBD was measured from the joint surface based on 5 clinically relevant topographic zones. The correlation of the wear pattern with the SBD distribution was investigated. Results: The glenoid subarticular layers could be separated into distinct regions: calcified cartilage (≤1.5mm), subchondral plate (2-4.5mm) and cancellous bone (≥5mm). There were significant differences in SBD among these layers within and between patients with concentric and eccentric wear patterns. In concentric glenoids, the SBD distribution was homogeneous, with greater mineralization in the central zone, 1,749.1±162.3 Hounsfield units (HU) (at 2.5mm), compared with the posterior, anterior, and superior zones (. P<.001). In the eccentric group, the SBD distribution was inhomogeneous. Mineralization was greatest in the posterior zone, 1,739.0±172.6 HU (at 2.5mm), followed by the inferior zone, 1,722.1±186.6 HU (at 3mm). Conclusion: This study represents the first study using CT-OAM to evaluate the 3-dimensional SBD distribution of the glenoid vault for different arthritic wear patterns. The study findings indicate that the SBD distribution is dependent on (1) depth from the articular surface, (2) topographic zone, and (3) wear pattern. CT-OAM may be an effective tool to assist in preoperative planning for shoulder arthroplasty. © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees.


Nayak A.N.,Phillip Spiegel Orthopaedic Research Laboratory | Gutierrez S.,Phillip Spiegel Orthopaedic Research Laboratory | Billys J.B.,Spinal USA | Santoni B.G.,Phillip Spiegel Orthopaedic Research Laboratory | Castellvi A.E.,Spinal USA
Spine Journal | Year: 2013

Background context: The lateral transpsoas approach to interbody fusion is gaining popularity because of its minimally invasive nature and resultant indirect neurologic decompression. The acute biomechanical stability of the lateral approach to interbody fusion is dependent on the type of supplemental internal fixation used. The two-hole lateral plate (LP) has been approved for clinical use for added stabilization after cage instrumentation. However, little biomechanical data exist comparing LP fixation with bilateral pedicle screw and rod (PSR) fixation. Purpose: To biomechanically compare the acute stabilizing effects of the two-hole LP and bilateral PSR fusion constructs in lumbar spines instrumented with a lateral cage at two contiguous levels. Study design: Biomechanical laboratory study of human cadaveric lumbar spines. Methods: Eighteen L1-S1 cadaveric lumbar spines were instrumented with lateral cages at L3-L4 and L4-L5 after intact kinematic analysis. Specimens (n=9 each) were allocated for supplemental instrumentation with either LP or PSR. Intact versus instrumented range of motion was evaluated for all specimens by applying pure moments (±7.5 Nm) in flexion/extension, lateral bending (LB) (left+right), and axial rotation (AR) (left+right). Instrumented spines were later subjected to 500 cycles of loading in all three planes, and interbody cage translations were quantified using a nonradiographic technique. Results: Lateral plate fixation significantly reduced ROM (p<.05) at both lumbar levels (flexion/extension: 49.5%; LB: 67.3%; AR: 48.2%) relative to the intact condition. Pedicle screw and rod fixation afforded the greatest ROM reductions (p<.05) relative to the intact condition (flexion/extension: 85.6%; LB: 91.4%; AR: 61.1%). On average, the largest interbody cage translations were measured in both fixation groups in the anterior-posterior direction during cyclic AR. Conclusions: Based on these biomechanical findings, PSR fixation maximizes stability after lateral interbody cage placement. The nonradiographic technique served to quantify migration of implanted hardware and may be implemented as an effective laboratory tool for surgeons and engineers to better understand mechanical behavior of spinal implants. © 2013 Elsevier Inc. All rights reserved.


Stein M.I.,University of South Florida | Nayak A.N.,Phillip Spiegel Orthopaedic Research Laboratory | Gaskins III R.B.,Phillip Spiegel Orthopaedic Research Laboratory | Cabezas A.F.,Phillip Spiegel Orthopaedic Research Laboratory | And 2 more authors.
Spine Journal | Year: 2014

Background context No profile, integrated interbody cages are designed to act as implants for cervical spine fusion, which obviates the need for additional internal fixation, combining the functionality of an interbody device and the stabilizing benefits of an anterior cervical plate. Biomechanical data are needed to determine if integrated interbody constructs afford similar stability to anterior plating in single-level cervical spine fusion constructs. Purpose The purpose of this study was to biomechanically quantify the acute stabilizing effect conferred by a single low-profile device design with three integrated screws ("anchored cage"), and compare the range of motion reductions to those conferred by a standard four-hole rigid anterior plate following instrumentation at the C5-C6 level. We hypothesized that the anchored cage would confer comparable postoperative segmental rigidity to the cage and anterior plate construct. Study design Biomechanical laboratory study of human cadaveric spines. Methods Seven human cadaveric cervical spines (C3-C7) were biomechanically evaluated using a nondestructive, nonconstraining, pure-moment loading protocol with loads applied in flexion, extension, lateral bending (right+left), and axial rotation (left+right) for the intact and instrumented conditions. Range of motion (ROM) at the instrumented level was the primary biomechanical outcome. Spines were loaded quasi-statically up to 1.5 N-m in 0.5 N-m increments and ROM at the C5-C6 index level was recorded. Each specimen was tested in the following conditions: 1. Intact 2. Discectomy+anchored cage (STA) 3. Anchored cage (screws removed)+anterior locking plate (ALP) 4. Anchored cage only, without screws or plates (CO) Results ROM at the C5-C6 level was not statistically different in any motion plane between the STA and ALP treatment conditions (p>.407). STA demonstrated significant reductions in flexion/extension, lateral bending, and axial rotation ROM when compared with the CO condition (p<.022). Conclusions In this in vitro biomechanical study, the anchored cage with three integrated screws afforded biomechanical stability comparable to that of the standard interbody cage+anterior plate cervical spine fusion approach. Due to its low profile design, this anchored cage device may avoid morbidities associated with standard anterior plating, such as dysphagia. © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

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