Publications by authors named "Nicholas Vaudreuil"

19 Publications

  • Page 1 of 1

Impact of COVID-19 on Recovered Athletes Returning to Competitive Play in the NBA "Bubble".

Orthop J Sports Med 2021 Mar 24;9(3):23259671211004531. Epub 2021 Mar 24.

Department of Orthopedic Sports Medicine, Cedars-Sinai Kerlan-Jobe Institute, Los Angeles, California, USA.

Background: The global pandemic caused by COVID-19 has had far-reaching implications for the world of professional sports. The National Basketball Association (NBA) suspended active regular season play in 2020 after a player tested positive for SARS-CoV-2. No previous studies have examined the impact of COVID-19 on return to play in the NBA.

Purpose/hypothesis: The purpose of this study was to examine performance measures for NBA players who had recovered from COVID-19 and returned to play in the NBA bubble. We hypothesized that these athletes would play fewer minutes and have decreased performance statistics compared with performance during the 2019-2020 regular season prior to the lockdown and with career averages.

Study Design: Case series; Level of evidence, 4.

Methods: NBA players positive for SARS-CoV-2 who played in both the 2019-2020 regular season and the NBA bubble were identified. Data collected included player demographics and player performance statistics.

Results: A total of 20 players were included in the study. Players who had recovered from COVID-19 played significantly fewer minutes per game in the NBA bubble (25.8 vs 28.7; = .04) and made fewer field goals per game (4.6 vs 5.4; = .02) compared with the season prior to shutdown. While NBA bubble players demonstrated slight decreases in averages for points ( = .06), rebounds ( =.13), assists ( = .23), steals ( = .30), and blocks ( = .71) per game, these were not statistically significant. Aside from an increase in made free throws per game during the bubble (3.3 vs 2.8; = .04), player performance was not significantly different from career averages.

Conclusion: For players who tested positive for SARS-CoV-2 prior to playing in the NBA bubble, the current study demonstrated that despite playing significantly fewer minutes per game, performance was not statistically different from either their pre-COVID 2019-2020 level of play or from their career averages.
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http://dx.doi.org/10.1177/23259671211004531DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8010822PMC
March 2021

Use of Fondaparinux Following Elective Lumbar Spine Surgery Is Associated With a Reduction in Symptomatic Venous Thromboembolism.

Global Spine J 2020 Oct 30;10(7):844-850. Epub 2019 Sep 30.

6595University of Pittsburgh Medical Center, Pittsburgh, PA, USA.

Study Design: Retrospective cohort study.

Objective: To assess the impact of fondaparinux on venous thromboembolism (VTE) following elective lumbar spine surgery in high-risk patients.

Methods: Matched patient cohorts who did or did not receive inpatient fondaparinux starting postoperative day 2 following elective lumbar spine surgery were compared. All patients received 1 month of acetyl salicylic acid 325 mg following discharge. The primary outcome was a symptomatic DVT (deep vein thrombosis) or PE (pulmonary embolus) within 30 days of surgery. Secondary outcomes included prolonged wound drainage, epidural hematoma, and transfusion.

Results: A significantly higher number of DVTs were diagnosed in the group that did not receive inpatient VTE prophylaxis (3/102, 2.9%) compared with the fondaparinux group (0/275, 0%, = .02). Increased wound drainage was seen in 18.5% of patients administered fondaparinux, compared with 25.5% of untreated patients ( = .15). Deep infections were equivalent (2.2% with fondaparinux vs 4.9% control, = .18). No epidural hematomas were noted, and the number of transfusions after postoperative day 2 and 90-day return to operating room rates were equivalent.

Conclusions: Patients receiving fondaparinux had lower rates of symptomatic DVT and PE and a favorable complication profile when compared with matched controls. The retrospective nature of this work limits the safety and efficacy claims that can be made about the use of fondaparinux to prevent VTE in elective lumbar spine surgery patients. Importantly, this work highlights the potential safety of this regimen, permitting future high-quality trials.
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http://dx.doi.org/10.1177/2192568219878418DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7485070PMC
October 2020

Rabbit Annulus Fibrosus Cells Express Neuropeptide Y, Which Is Influenced by Mechanical and Inflammatory Stress.

Neurospine 2020 Mar 31;17(1):69-76. Epub 2020 Mar 31.

Department of Orthopaedic Surgery, Ferguson Laboratory for Orthopaedic Research, University of Pittsburgh, Pittsburgh, PA, USA.

Objective: Rabbit annulus fibrosus (AF) cells were exposed to isolated or combined mechanical and inflammatory stress to examine the expression of neuropeptide Y (NPY). This study aims to explore the ability of AF cells to produce NPY in response to mechanical and inflammatory stress.

Methods: Lumbar AF cells of 6- to 8-month-old female New Zealand white rabbits were harvested and exposed to combinations of inflammatory (interleukin-1β) and mechanical (6% or 18%) tensile stress using the Flexcell System. NPY concentrations were measured in the media via enzyme-linked immunosorbent assay. The presence of NPY receptor-type 1 (NPY-1R) in AF cells of rabbit intervertebral discs was also analyzed via immunohistochemistry and immunofluorescence.

Results: Exposure to inflammatory stimuli showed a significant increase in the amount of NPY expression compared to control AF cells. Mechanical strain alone did not result in a significant difference in NPY expression. While combined inflammatory and mechanical stress did not demonstrate an increase in NPY expression at low (6%) levels of strain, at 18% strain, there was a large-though not statistically significant-increase in NPY expression under conditions of inflammatory stress. Lastly, immunofluorescence and immunohistochemistry of AF cells and tissue, respectively, demonstrated the presence of NPY-1R.

Conclusion: These findings demonstrate that rabbit AF cells are capable of expressing NPY, and expression is enhanced in response to inflammatory and mechanical stress. Because both inflammatory and mechanical stress contribute to intervertebral disc degeneration (IDD), this observation raises the potential of a mechanistic link between low back pain and IDD.
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http://dx.doi.org/10.14245/ns.2040046.023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7136102PMC
March 2020

Evaluation and Treatment of Borderline Dysplasia: Moving Beyond the Lateral Center Edge Angle.

Curr Rev Musculoskelet Med 2020 Feb;13(1):28-37

Department of Orthopaedic Surgery, UPMC Children's Hospital of Pittsburgh, 4401 Penn Ave. Second Floor, Pittsburgh, PA, 15224, USA.

Purpose Of Review: The purpose of this manuscript is to 1 define the features associated with borderline acetabular dysplasia and 2 review current status of diagnostic algorithms and treatment options for borderline dysplasia.

Recent Findings: Acetabular dysplasia is a common cause of hip pain secondary to insufficient coverage of the femoral head by the bony acetabulum. Historical classification of acetabular dysplasia has utilized the lateral center edge angle (LCEA); values above 25° are normal and below 20° are considered pathologic. Borderline dysplasia describes hips with LCEA between 20 and 25; treatment of these patients is controversial. While many studies utilize LCEA in classification of borderline dysplasia, isolated reliance on measurement of lateral femoral head coverage to define severity of undercoverage will continue to mislabel morphology. Thorough assessment of the characteristics of mild acetabular undercoverage is necessary for future studies, which will allow effective comparisons of results between hip arthroscopy and periacetabular osteotomy.
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http://dx.doi.org/10.1007/s12178-020-09599-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7083976PMC
February 2020

Ambulation milestones in post-operative physical therapy after total knee arthroplasty: how can we improve short-term outcomes?

Physiother Theory Pract 2019 Dec 18:1-7. Epub 2019 Dec 18.

Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.

: Post-operative day (POD) 0 physical therapy (PT) after total knee arthroplasty (TKA) has been associated with improved outcomes such as shorter hospital length of stay (LOS), though patient performance is variable. The purpose of this study was to evaluate PT performance and determine whether this affected LOS or discharge to home.: Retrospective review including 412 patients who underwent TKA over 1 year. Specific data assessed included details about demographics, surgery/recovery, PT, LOS, and discharge destination.: Overall, 88.8% (366/412) of patients received POD 0 PT. About 73.9% of patients who did not receive POD 0 PT were prevented from doing so by reasons that kept them off of the orthopedic inpatient floor. Patients who walked greater than 10 feet on POD 0 or 100 feet on POD 1 were significantly more likely to have a shorter LOS and more likely to be discharged to home.: Objective milestones of walking 10 feet on POD 0 and 100 feet on POD 1 were associated with improved short-term outcomes. These performance markers may be useful for stratifying which patients are meeting milestones for early discharge. Late arrival to inpatient floor had the strongest associations with inability to perform PT.
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http://dx.doi.org/10.1080/09593985.2019.1706212DOI Listing
December 2019

Biomechanical contribution of the alar ligaments to upper cervical stability.

J Biomech 2020 01 23;99:109508. Epub 2019 Nov 23.

Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, United States; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States. Electronic address:

Acute and chronic whiplash-associated disorders pose a significant healthcare burden due to chronic pain, which is associated with upper cervical instability resulting from ligamentous injury. No standard measure exists for diagnosing alar ligament injury and imaging findings vary widely. Multiple physical examination maneuvers are used to diagnose alar ligament injury including the C2 Spinous Kick, Flexion-Rotation, and Bending-Rotation tests. The objective of the current study was to determine the mechanical contribution of the alar ligaments to upper cervical stability and quantify the biomechanical changes seen during simulated clinical examinations after alar ligament injury. Eight cadaveric C0-C3 specimens were evaluated using a robotic testing system. Range of motion and moment at the end of intact specimen replay were the primary outcomes. Clinical examinations were simulated by rotation through two axes as performed during physical examination. Intact, unilateral and bilateral alar ligament injury states were tested. Unilateral alar ligament injury led to significant increases in lateral bending (12.0 ± 7.2%, p < 0.05), axial rotation (4.1 ± 2.4%, p < 0.05), and flexion-extension (5.3 ± 4.3%, p < 0.05) compared with intact specimens. The alar ligaments also contributed to resistance to intact motion in extension (13.4 ± 6.6%, p < 0.05), flexion (4.4 ± 2.2%, p < 0.05), axial rotation (19.3 ± 2.7%, p < 0.05), and lateral bending (16.0 ± 2.8%, p < 0.05). The C2 Spinous Kick Test showed the largest percentage change (-23.0 ± 14.8%), and the Bending-Rotation Test towards the side of injury significantly increased axial rotation by the largest absolute magnitude (5.5° ± 5.1°). Overall, quantifiable changes to motion measured during simulated physical examinations were found, but the ability of a clinician to feel these changes remains unknown.
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http://dx.doi.org/10.1016/j.jbiomech.2019.109508DOI Listing
January 2020

The effect of tendon rotation on distal biceps repair.

JSES Open Access 2019 Oct 11;3(3):225-231. Epub 2019 Sep 11.

Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA, USA.

Background: The distal biceps tendon externally rotates from proximal to distal before inserting onto the radius. Our hypothesis is that an externally rotated (anatomic) repair would re-create native supination moment arm and flexion force, whereas an internally rotated (nonanatomic) repair would result in reduced force transmission.

Methods: The mechanical tests performed in this study measured isometric moment arms and elbow flexion force using a validated elbow simulator as previously published. Mechanical testing was performed on 8 native cadaveric elbows (61 ± 15 years). The distal biceps tendons in all specimens were then incised from their footprint and repaired with anatomic and nonanatomic tendon rotations. After each repair, the specimens were retested. The repair sequence was randomly assigned.

Results: Gross observation showed repair site bunching with the nonanatomic repairs. There was no statistical difference in the moment arms between the native, anatomic, and nonanatomic rotations for the 3 forearm angles ( ≥ .352). Analysis showed no statistical difference in flexion force ratio for the elbow at 90° ( ≥ .283).

Discussion: The study showed that biceps tendon rotation does not play a role in supination moment arm or flexion force. Twisting the distal biceps tendon around the tendon axis does not change the direction of its applied force on the tuberosity. Tendon bunching in nonanatomic reattachments increases repair site width, which may lead to tendon-ulnar impingement during forearm rotation.
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http://dx.doi.org/10.1016/j.jses.2019.06.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6835028PMC
October 2019

Novel use of telescoping growth rods in treatment of early onset scoliosis: An and study in a porcine model.

JOR Spine 2018 Dec 8;1(4):e1035. Epub 2018 Oct 8.

Department of Orthopaedic Surgery, School of Medicine University of Pittsburgh Pittsburgh Pennsylvania.

Introduction: Treatment of early-onset scoliosis (EOS) can be difficult. Various forms of growing rods exist to correct deformity while delaying definitive spinal fusion. The disadvantage of traditional growing rods is need for repeated surgical lengthening procedures. Telescoping growth rods (TelGR) are a prototype new, guided growth technology with a rod mechanism that allows spontaneous longitudinal growth over time without manual lengthening. We hypothesized that the TelGR system will permit unrestricted growth with limited complications through 12 weeks , and that the range of motion (RoM) in each of three directions and stiffness of the TelGR system would not be significantly different than the rigid rod system .

Materials And Methods: : Six immature pigs were surgically implanted with TelGR with cephalad fixation at T6-7 and caudal fixation at T14-L1. Radiographs of the involved vertebral segments were measured postoperatively and after 12 weeks. : A robotic testing system was utilized for flexibility tests in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) of eight immature porcine specimens (T3-T15). Testing was performed on both dual rigid rods and bilateral TelGR with instrumentation at T4-5 and T13-14.

Results: : Over the 12-week period, the rod length of the TelGR increased an average of 65 mm. : TelGR demonstrated significantly increased motion in LB and AR RoM compared with rigid rods. No difference was noted in FE RoM.

Discussion: The results in this study showed expected skeletal growth with spines instrumented with TelGR. findings of increased RoM in AR and LB suggest that the TelGR system may be less rigid than traditional growing rods. Treatment with TelGR might, if proven efficacious in the clinical setting, decrease the need for repeated surgical intervention compared with traditional growing rods. This study adds to the limited body of biomechanical evidence examining guided growth technology.
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http://dx.doi.org/10.1002/jsp2.1035DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6686829PMC
December 2018

Cervical Spine Fractures: Who Really Needs CT Angiography?

Spine (Phila Pa 1976) 2019 Dec;44(23):1661-1667

Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA.

Study Design: Retrospective cohort study.

Objective: Compare a novel two-step algorithm for indicating a computed tomography angiography (CTA) in the setting of a cervical spine fracture with established gold standard criteria.

Summary Of Background Data: As CTA permits the rapid detection of blunt cerebrovascular injuries (BCVI), screening criteria for its use have broadened. However, more recent work warns of the potential for the overdiagnosis of BCVI, which must be considered with the adoption of broad criteria.

Methods: A novel two-step metric for indicating CTA screening was compared with the American College of Surgeons guidelines and the expanded Denver Criteria using patients who presented with cervical spine fractures to a tertiary-level 1 trauma center from January 1, 2012 to January 1, 2016. The ability for each metric to identify BCVI and posterior circulation strokes that occurred during this period was assessed.

Results: A total of 721 patients with cervical fractures were included, of whom 417 underwent CTAs (57.8%). Sixty-eight BCVIs and seven strokes were diagnosed in this cohort. All algorithms detected an equivalent number of BCVIs (52 with the novel metric, 54 with the ACS and Denver Criteria, P = 0.84) and strokes (7/7, 100% with the novel metric, 6/7, 85.7% with the ACS and Denver Criteria, P = 1.0). However, 63% fewer scans would have been needed with the proposed screening algorithm compared with the ACS or Denver Criteria (261/721, 36.2% of all patients with our criteria vs. 413/721, 57.3% with the ACS standard and 417/721, 57.8%) with the Denver Criteria, P < 0.0002 for each).

Conclusion: A two-step criterion based on mechanism of injury and patient factors is a potentially useful guide for identifying patients at risk of BCVI and stroke after cervical spine fractures. Further prospective analyses are required prior to widespread clinical adoption.

Level Of Evidence: 4.
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http://dx.doi.org/10.1097/BRS.0000000000003163DOI Listing
December 2019

Biomechanical Analysis of a Growing Rod with Sliding Pedicle Screw System for Early-Onset Scoliosis.

J Healthc Eng 2019 12;2019:9535070. Epub 2019 Jun 12.

Ferguson Laboratory for Spine Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.

Early-onset scoliosis (EOS) remains a challenging condition for which current nonfusion surgeries require iterative lengthening surgeries. A growing rod with sliding pedicle screw system (GRSPSS) was developed to treat spinal deformities without repeated operative lengthening. This study was performed to evaluate whether GRSPSS had similar stability as a conventional pedicle screw system to maintain deformity correction. A serial-linkage robotic manipulator with a six-axis load cell positioned on the end-effector was utilized to evaluate the mechanical stability of the GRSPSS versus conventional fixed scoliosis instrumentation. Ten skeletally mature thoracic female Katahdin sheep spines (T4-L1) were subjected to 2.5 Nm of flexion-extension (FE), lateral bending (LB), and axial rotation (AR) in 2° increments for each state. The overall range of motion (ROM), apical segment ROM, and stiffness were calculated and reported. A two-tailed paired -test was used to detect significant differences ( < 0.05) between the fixed group and GRSPSS fixation. There were no significant differences in overall range of motion (ROM), apical segment ROM, or stiffness for FE or LB between the GRSPSS group and fixed group. In AR, the GRSPSS group showed increased ROM compared to the fixed group for the overall spine (36.0° versus 19.2°, < 0.01) and for the instrumented T8-T10 segments (7.0° versus 2.9°, =0.02). Similarly, the fixed rod elastic zone (EZ) stiffness was significantly greater than the GRSPSS EZ stiffness (0.29 N/m versus 0.17 N/m, < 0.001). The space around the rod allows for the increased AR observed with the GRSPSS fusion technique and is necessary for axial growth. The GRSPSS fusion model shows equivalent flexion and LB stability to current fusion models and represents a stable fusion technique and may allow for longitudinal growth during childhood.
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http://dx.doi.org/10.1155/2019/9535070DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6594281PMC
September 2020

Biomechanical Analysis of Wide Posterior Releases Compared With Inferior Facetectomy and Discectomy in the Thoracolumbar and Lumbar Spine.

Spine Deform 2019 05;7(3):404-409

Department of Orthopaedics, University of Pittsburgh Ferguson Laboratory for Orthopaedic Research, 200 Lothrop St., E1658, University of Pittsburgh, Pittsburgh, PA 15213, USA.

Study Design: In vitro biomechanical analysis.

Objectives: Compare the destabilizing effects of anterior discectomy to posterior spinal releases.

Summary Of Background Data: Posterior release and pedicle screw fixation has become the accepted form of treatment for lumbar and thoracolumbar pediatric scoliotic spinal deformity. A biomechanical evaluation of posterior releases with comparison to traditional anterior releases has not been reported in the lumbar spine.

Methods: Eleven fresh-frozen human thoracolumbar specimens (T9-L5) were tested by a robotic manipulator (Staubli RX90; moment target of 5.0 Nm, force target of 50 N) in axial rotation (AR), plus lateral and anterior translation (LT and AT). Specimens underwent either sequential anterior release (partial and full discectomy) or posterior release (inferior facetectomy and wide posterior release) from T10 to L4. Partial discectomy retained the posterior 50% of disc and posterior longitudinal ligament, whereas full discectomy removed all of the disc and PLL. Wide posterior release included total facetectomy plus ligamentum flavum and spinous process resection.

Results: Inferior facetectomy produced an average increase of 1.5° ± 1.0° (p = .0625), 1.0 ± 0.8 mm (p = .0313), and 0.2 ± 0.3 mm (p = .156) in AR, LT, and AT, respectively. Compared with partial facetectomy, wide posterior release produced an average additional increase of 8.1° ± 4.0° (p = .0312), 2.0 ± 2.2 mm (p = .4062), and 1.1 ± 1.0 mm (p = .0625) in AR, LT, and AT, respectively. Full discectomy produced 201%, 161%, and 153% of the motion relative to wide posterior release in AR, LT, and AT, respectively (p = .0043, .0087, and .0173). Partial discectomy and wide posterior release proved statistically equivalent.

Conclusions: Wide posterior release of the thoracolumbar spine allows significant correction and may be superior to inferior facetectomy in axial rotation. Although complete discectomy with PLL resection would likely allow greater correction, a more clinically realistic partial discectomy confers similar corrective potential in vitro compared with wide posterior release.

Level Of Evidence: Not applicable.
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http://dx.doi.org/10.1016/j.jspd.2018.09.004DOI Listing
May 2019

The Pivot Shift: Current Experimental Methodology and Clinical Utility for Anterior Cruciate Ligament Rupture and Associated Injury.

Curr Rev Musculoskelet Med 2019 Mar;12(1):41-49

Department of Orthopaedic Surgery, UPMC Rooney Sports Complex, University of Pittsburgh Medical Center, 3200 S. Water St., Pittsburgh, PA, 15203, USA.

Purpose Of Review: The purpose of this manuscript is to (1) examine the history, techniques, and methodology behind quantitative pivot shift investigations to date and (2) review the current status of pivot shift research for its clinical utility for management of anterior cruciate ligament (ACL) rupture with associated injuries including the anterolateral complex (ALC).

Recent Findings: The pivot shift is a useful physical exam maneuver for diagnosis of rotatory instability related to ACL tear. Recent evidence suggests that the pivot shift is multifactorial and can be seen in the presence of ACL tear with concomitant injury to secondary stabilizers or with predisposing anatomical factors. The presence of a pivot shift post-operatively is associated with poorer outcomes after ACL reconstruction. Recent clinical and biomechanical investigations can help guide clinicians in utilizing pivot shift in diagnosis and surgical planning. Further research is needed to clarify optimal management of ALC in addition to ACL injury.
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http://dx.doi.org/10.1007/s12178-019-09529-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6388573PMC
March 2019

Photopolymerizable biogel scaffold seeded with mesenchymal stem cells: safety and efficacy evaluation of novel treatment for intervertebral disc degeneration.

J Orthop Res 2019 06 16;37(6):1451-1459. Epub 2019 Jan 16.

Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.

Tissue engineering approaches to treatment of intervertebral disc degeneration (IDD) represent a novel avenue of addressing the biologic basis of this disease. However, such approaches remain limited by their invasive nature and disruption to the annular fibrosis (AF). This study sought to explore a new minimally-invasive tissue-engineering approach utilizing an injection of a photopolymerizable biogel scaffold seeded with mesenchymal stem cells (MSCs) directly into the nucleus pulposus (NP). This study was performed using rabbit specimens for both in vivo and in vitro outcome measures. The treatment in this study was performed by injecting 25 μl of 10% (w/v) methacrylated gelatin biogel with 0.15% (w/v) lithium phenyl 2,4,6-trimethylbenzoylphosphinate (LAP) and rabbit MSCs (1 × 10 ) cells/ml into the NP. Samples were then photopolymerized in situ using non-ultraviolet light irradiation via a fiberoptic wire. For the in vitro arm of this study, gene expression analysis demonstrated increased anabolic activity in irradiated MSCs with and without biogel scaffolds. For the in vivo arm of this study, while GAG analysis did not demonstrate significant differences between groups, MRI analysis exhibited a trend toward improved NP matrix. Histological analysis was consistent with increased cellularity and less severe disc degeneration in the MSC + Gel group. However, osteophyte formation was noted in both Stab and MSC + Gel groups after the study period. Increased matrix gene expression of irradiated groups within in vitro studies indicates a photobiologic effect of 405 nm light. Despite promising anabolic actions, osteophyte formation and AF defects could not be avoided with implementation of this minimally-invasive tissue-engineering approach. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1451-1459, 2019.
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http://dx.doi.org/10.1002/jor.24208DOI Listing
June 2019

Biomechanical contributions of upper cervical ligamentous structures in Type II odontoid fractures.

J Biomech 2019 01 22;83:28-33. Epub 2018 Nov 22.

Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA. Electronic address:

Fractures of the odontoid present frequently in spinal trauma, and Type II odontoid fractures, occurring at the junction of the odontoid process and C2 vertebrae, represent the bulk of all traumatic odontoid fractures. It is currently unclear what soft-tissue stabilizers contribute to upper cervical motion in the setting of a Type II odontoid fracture, and evaluation of how concomitant injury contributes to cervical stability may inform surgical decision-making as well as allow for the creation of future, accurate, biomechanical models of the upper cervical spine. The objective of the current study was to determine the contribution of soft-tissue stabilizers in the upper cervical spine following a Type II odontoid fracture. Eight cadaveric C0-C2 specimens were evaluated using a robotic testing system with motion tracking. The unilateral facet capsule (UFC) and anterior longitudinal ligament (ALL) were serially resected to determine their biomechanical role following odontoid fracture. Range of motion (ROM) and moment at the end of intact specimen replay were the primary outcomes. We determined that fracture of the odontoid significantly increases motion and decreases resistance to intact motion for flexion-extension (FE), axial rotation (AR), and lateral bending (LB). Injury to the UFC increased AR by 3.2° and FE by 3.2°. ALL resection did not significantly increase ROM or decrease end-point moment. The UFC was determined to contribute to 19% of intact flexion resistance and 24% of intact AR resistance. Overall, we determined that Type II fracture of the odontoid is a significant biomechanical destabilizer and that concurrent injury to the UFC further increases upper cervical ROM and decreases resistance to motion in a cadaveric model of traumatic Type II odontoid fractures.
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http://dx.doi.org/10.1016/j.jbiomech.2018.11.014DOI Listing
January 2019

Prophylactic perioperative dexamethasone decreases the incidence of postoperative C5 palsies after a posterior cervical laminectomy and fusion.

Spine J 2019 02 22;19(2):253-260. Epub 2018 May 22.

Department of Orthopaedic Surgery, Ferguson Laboratory for Orthopaedic Research, University of Pittsburgh, E1643 Biomedical Science Tower, 200 Lothrop St, Pittsburgh, PA 15213, USA. Electronic address:

Background Context: Postoperative C5 palsy is a well-known complication of cervical decompression procedures. Studies have shown that posterior laminectomy and fusions confer the greatest risk of C5 palsy. Despite this, pharmacologic preventive measures remain unknown. We hypothesize that prophylactic perioperative dexamethasone (DEX) will decrease the rate of postoperative C5 palsy in patients undergoing a multilevel posterior cervical laminectomy and fusion.

Purpose: The purpose of this study was to assess the safety and efficacy of prophylactic perioperative DEX in decreasing the rate of postoperative C5 palsy.

Design: This is a retrospective, single-institution clinical study.

Patient Sample: The patient population included all patients undergoing multilevel posterior cervical laminectomy and instrumented fusion procedures for myeloradiculopathy or myelopathy, who also received a course of perioperative dexamethasone. Surgeries occurred between 2012 and 2017 at a single tertiary care center by a single surgeon with at least 1 year of follow-up. Patients who underwent decompression procedures other than multilevel posterior cervical laminectomy and instrumented fusions; had trauma, fracture; underwent decompression not including C5-level, insulin-dependent diabetes mellitus; and had documented adverse reactions to steroids were excluded.

Outcome Measures: Preoperative demographics and postoperative complications, including development of postoperative C5 palsy, were considered as outcome measures.

Materials And Methods: A total of 189 consecutive patients who underwent multilevel posterior cervical laminectomy and instrumented fusion and received prophylactic perioperative DEX were reviewed. The rate of C5 palsy was investigated and compared with our historical control rate of C5 palsy before the institutional implementation of perioperative DEX. Demographics were reviewed, and risk factor stratification was analyzed. The safety of using DEX was investigated by examining postoperative complications. The clinical course of patients who developed C5 palsy was then reported.

Results: Postoperative C5 palsy occurred in 5 of the 138 patients (3.6%) meeting the inclusion criteria. Patients receiving perioperative DEX had a significantly decreased rate of postoperative C5 palsy compared with those who did not (3.6% vs. 9.5%, p=.01). Age was the only risk factor that was significantly correlated with development of C5 palsy (72.71±7.76 vs. 61.07±10.59, p=.02). Infection, seroma, and wound complication rates were 2.8%, 2.17%, and 1.44%, respectively, in patients receiving prophylactic DEX. All five patients receiving DEX who developed C5 palsy recovered with no residual deficits at an average of 16.8 weeks postoperatively.

Conclusions: Perioperative prophylactic DEX therapy is a safe and effective way to decrease the incidence of C5 palsies in patients who undergo multilevel posterior laminectomy and fusion for myeloradiculopathy or myelopathy.
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http://dx.doi.org/10.1016/j.spinee.2018.05.031DOI Listing
February 2019

NSAID use in intervertebral disc degeneration: what are the effects on matrix homeostasis in vivo?

Spine J 2017 08 14;17(8):1163-1170. Epub 2017 Apr 14.

Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, 200 Lothrop St, EBST 1640, Pittsburgh, PA 15261, USA; Department of Physical Medicine and Rehabilitation, University of Pittsburgh Medical Center, 200 Lothrop St, EBST 1640, Pittsburgh, PA 15261, USA.

Background Context: Non-steroidal anti-inflammatory drugs (NSAIDs) are a widely used treatment for low back pain (LBP). Literature on NSAID use in articular cartilage has shown detrimental effects; however, minimal data exist to detail the effects of NSAIDs in intervertebral disc degeneration (IDD). As IDD is a major cause of LBP, we explored the effects of indomethacin, a commonly used NSAID, on disc matrix homeostasis in an animal model of IDD.

Purpose: This study aimed to determine the effects of oral indomethacin administration on IDD in an in vivo rabbit model. This study hypothesized that indomethacin use would accelerate the progression of IDD based upon serial imaging and tissue outcomes.

Study Design/setting: This was a laboratory-based, controlled, in vivo evaluation of the effects of oral indomethacin administration on rabbit intervertebral discs.

Methods: Six skeletally mature New Zealand white rabbits were divided into two groups: disc puncture alone to induce IDD (Puncture group) and disc puncture plus indomethacin (Punc+Ind group). The Punc+Ind group received daily administration of 6mg/kg oral indomethacin. Serial magnetic resonance imaging (MRI) was obtained at 0, 4, 8, and 12 weeks. The MRI index and the nucleus pulposus (NP) area were calculated. Discs were harvested at 12 weeks for determination of disc glycosaminoglycan (GAG) content, relative gene expression measured by real-time polymerase chain reaction, and histologic analyses.

Results: The MRI index and the NP area of punctured discs in the Punc+Ind group demonstrated no worsening of degeneration compared with the Puncture group. Histologic analysis was consistent with less severe disc degeneration in the Punc+Ind group. Minimal differences in gene expression of matrix genes were observed between Puncture and Punc+Ind groups. The GAG content was higher in animals receiving indomethacin in both annulus fibrosus and NP at adjacent uninjured discs.

Conclusions: Oral indomethacin administration did not result in acceleration of IDD in an in vivo rabbit model. Future research is needed to ascertain long-term effects of indomethacin and other NSAIDs on disc matrix homeostasis.
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http://dx.doi.org/10.1016/j.spinee.2017.04.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5538909PMC
August 2017

Comparison of Diabetic Charcot Patients With and Without Foot Wounds.

Foot Ankle Int 2017 Feb 24;38(2):140-148. Epub 2016 Oct 24.

3 Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.

Background: The primary aim of this study was to evaluate the outcomes of a series of patients with Charcot neuroarthropathy (CN) who were evaluated in a tertiary care setting. We hypothesized that those patients with CN who presented with a Charcot-related foot wound would have lower rates of successful limb salvage than patients who presented without a wound.

Methods: Two hundred forty-five patients (280 feet) were identified with diabetic CN during the time period from January 1, 2005, to June 1, 2015. This consecutive cohort of patients was treated by a single surgeon and had a mean age of 57.9 ± 10.0 years. Our CN patients were divided into 2 groups for the purpose of our analysis. Our study group included those patients who presented to our clinic with a Charcot-related foot wound. Our control group was composed of CN patients who presented without a Charcot-related foot wound.

Results: Overall, 78 feet (27.9%) were successfully treated nonoperatively and 202 feet (72.1%) required some type of surgery. Of the 202 feet that received surgery, 22 (10.9%) were not felt to be suitable for reconstruction and underwent a definitive transtibial amputation without an attempt at reconstruction. An additional 18 patients underwent soft tissue surgery, which included drainage of infection, posterior muscle group lengthening, or soft tissue reconstructive flap surgery. The remaining 162 feet underwent osseous surgery, which included ostectomies for osteomyelitis, exostectomies, osteotomies, and arthrodesis. Eighteen of the 180 limbs (10.0%) that underwent soft tissue or osseous reconstruction ultimately required a transtibial amputation, resulting in a successful limb salvage rate of 90.0%. Thirty-five amputations were performed in 164 feet (21.3%) with Charcot-related foot wounds compared with 5 amputations in 116 feet (4.5%) without Charcot-related foot wounds (OR 6.02, 95% CI 2.28-15.91, P < .0001).

Conclusion: The presence of a Charcot-related foot wound at presentation increased the likelihood of a major lower extremity amputation by a factor of 6. Other risk factors that were associated with major amputation in patients included active infection at presentation, nonunion/instability after reconstruction, and a postoperative wound problem. The overall rate of successful limb salvage in patients deemed reconstructive candidates was 90%.

Level Of Clinical Evidence: Level III, retrospective, case-control study.
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http://dx.doi.org/10.1177/1071100716673985DOI Listing
February 2017

Limb Salvage After Failed Initial Operative Management of Bimalleolar Ankle Fractures in Diabetic Neuropathy.

Foot Ankle Int 2017 Mar 13;38(3):248-254. Epub 2016 Nov 13.

2 Department of Orthopaedic Surgery, University of Texas Southwestern, Dallas, TX, USA.

Background: Ankle fractures in patients with diabetes mellitus (DM) can be difficult to manage, especially in the presence of peripheral neuropathy. In patients who fail initial operative management, attempts at limb salvage can be challenging, and no clear treatment algorithm exists. This study examined outcomes of different procedures performed for limb salvage in this population.

Methods: This study retrospectively reviewed 17 patients with DM complicated by peripheral neuropathy who sustained a bimalleolar ankle fracture and failed initial operative management. Patients were treated with revision open reduction internal fixation (ORIF) (3/17), closed reduction external fixation (CREF) (8/17), or primary ankle joint fusion (3/17 tibiotalocalcaneal fusion with hindfoot nail [TTCN] and 3/17 with tibiotalar arthrodesis using plates and screws [TTA]). Median follow-up was 20 months.

Results: The overall rate of limb salvage was 82.3% (14/17). All patients who went on to amputation presented with infection and were treated initially with CREF (3/3). All patients who achieved successful limb salvage ended up with a clinically fused ankle joint (14/14); 9 underwent a primary or delayed formal fusion and 5 had a clinically fused ankle joint at study conclusion after undergoing revision ORIF or CREF with adjunctive procedures.

Conclusion: This small study suggests that in this complicated group of patients it is difficult to achieve limb salvage with an end result of a functional ankle joint. CREF can be a viable option in cases where underlying infection or poor bone quality is present. Treatment with revision ORIF frequently requires supplementary external fixator or tibiotalar Steinman pin placement for additional stability. All patients who underwent revision ORIF ended up with clinically fused ankle joints at the end of the study period. Primary fusion procedures (TTA, TTCN) were associated with a high rate of limb salvage and a decreased number of operations.

Level Of Evidence: Level III, retrospective case series.
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http://dx.doi.org/10.1177/1071100716676063DOI Listing
March 2017

Comparison of transfer sites for flexor digitorum longus in a cadaveric adult acquired flatfoot model.

J Orthop Res 2014 Jan 21;32(1):102-9. Epub 2013 Sep 21.

RR&D Center of Excellence for Limb Loss Prevention and Prosthetic Engineering, VA Puget Sound, Seattle, Washington, 98108; School of Medicine, University of Washington, Seattle, Washington, 98195.

Posterior tibialis tendon (PTT) dysfunction (PTTD) is associated with adult acquired flatfoot deformity. PTTD is commonly treated with a flexor digitorum longus (FDL) tendon transfer (FDLTT) to the navicular (NAV), medial cuneiform (CUN), or distal residuum of the degraded PTT (rPTT). We assessed the kinetic and kinematic outcomes of these three attachment sites using cadaveric gait simulation. Three transfer locations (NAV, CUN, rPTT) were tested on seven prepared flatfoot models using a robotic gait simulator (RGS). The FDLTT procedures were simulated by pulling on the PTT with biomechanically realistic FDL forces (rPTT) or by pulling on the transected FDL tendon after fixation to the navicular or medial cuneiform (NAV and CUN, respectively). Plantar pressure and foot bone motion were quantified. Peak plantar pressure significantly decreased from the flatfoot condition at the first metatarsal (NAV) and hallux (CUN). No difference was found in the medial-lateral center of pressure. Kinematic findings showed minimal differences between flatfoot and FDLTT specimens. The three locations demonstrated only minimal differences from the flatfoot condition, with the NAV and CUN procedures resulting in decreased medial pressures. Functionally, all three surgical procedures performed similarly.
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http://dx.doi.org/10.1002/jor.22488DOI Listing
January 2014