Publications by authors named "Richard A Wawrose"

13 Publications

  • Page 1 of 1

Pre-Operative Bariatric Surgery Imparts An Increased Risk of Infection, Re-Admission and Operative Intervention Following Elective Instrumented Lumbar Fusion.

Global Spine J 2021 Apr 28:21925682211011601. Epub 2021 Apr 28.

Department of Orthopaedic Surgery, 6595University of Pittsburgh Medical Center, PA, USA.

Study Design: Retrospective cohort study.

Objectives: To evaluate the impact of bariatric surgery on patient outcomes following elective instrumented lumbar fusion.

Methods: A retrospective review of a prospectively collected database was performed. Patients who underwent a bariatric procedure prior to an elective instrumented lumbar fusion were evaluated. Lumbar procedures were performed at a large academic medical center from 1/1/2012 to 1/1/2018. The primary outcome was surgical site infection (SSI) requiring surgical debridement. Secondary outcomes were prolonged wound drainage requiring treatment, implant failure requiring revision, revision secondary to adjacent segment disease (ASD), and chronic pain states. A randomly selected, surgeon and comorbidity-matched group of 59 patients that underwent an elective lumbar fusion during that period was used as a control. Statistical analysis was performed using Student's two-way t-tests for continuous data, with significance defined as < .05.

Results: Twenty-five patients were identified who underwent bariatric surgery prior to elective lumbar fusion. Mean follow-up was 2.4 ± 1.9 years in the bariatric group vs. 1.5 ± 1.3 years in the control group. Patients with a history of bariatric surgery had an increased incidence of SSI that required operative debridement, revision surgery due to ASD, and a higher incidence of chronic pain. Prolonged wound drainage and implant failure were equivalent between groups.

Conclusion: In the present study, bariatric surgery prior to elective instrumented lumbar fusion was associated increased risk of surgical site infection, adjacent segment disease and chronic pain when compared to non-bariatric patients.
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http://dx.doi.org/10.1177/21925682211011601DOI Listing
April 2021

Correction to: ISSLS prize in basic science 2021: a novel inducible system to regulate transgene expression of TIMP1.

Eur Spine J 2021 Mar 7. Epub 2021 Mar 7.

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

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http://dx.doi.org/10.1007/s00586-021-06783-7DOI Listing
March 2021

ISSLS prize in basic science 2021: a novel inducible system to regulate transgene expression of TIMP1.

Eur Spine J 2021 Feb 1. Epub 2021 Feb 1.

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

Purpose: Inflammatory and oxidative stress upregulates matrix metalloproteinase (MMP) activity, leading to intervertebral disc degeneration (IDD). Gene therapy using human tissue inhibitor of metalloproteinase 1 (hTIMP1) has effectively treated IDD in animal models. However, persistent unregulated transgene expression may have negative side effects. We developed a recombinant adeno-associated viral (AAV) gene vector, AAV-NFκB-hTIMP1, that only expresses the hTIMP1 transgene under conditions of stress.

Methods: Rabbit disc cells were transfected or transduced with AAV-CMV-hTIMP1, which constitutively expresses hTIMP1, or AAV-NFκB-hTIMP1. Disc cells were selectively treated with IL-1β. NFκB activation was verified by nuclear translocation. hTIMP1 mRNA and protein expression were measured by RT-PCR and ELISA, respectively. MMP activity was measured by following cleavage of a fluorogenic substrate.

Results: IL-1β stimulation activated NFκB demonstrating that IL-1β was a surrogate for inflammatory stress. Stimulating AAV-NFκB-hTIMP1 cells with IL-1β increased hTIMP1 expression compared to unstimulated cells. AAV-CMV-hTIMP1 cells demonstrated high levels of hTIMP1 expression regardless of IL-1β stimulation. hTIMP1 expression was comparable between IL-1β stimulated AAV-NFκB-hTIMP1 cells and AAV-CMV-hTIMP1 cells. MMP activity was decreased in AAV-NFκB-hTIMP1 cells compared to baseline levels or cells exposed to IL-1β.

Conclusion: AAV-NFκB-hTIMP1 is a novel inducible transgene delivery system. NFκB regulatory elements ensure that hTIMP1 expression occurs only with inflammation, which is central to IDD development. Unlike previous inducible systems, the AAV-NFκB-hTIMP1 construct is dependent on endogenous factors, which minimizes potential side effects caused by constitutive transgene overexpression. It also prevents the unnecessary production of transgene products in cells that do not require therapy.
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http://dx.doi.org/10.1007/s00586-021-06728-0DOI Listing
February 2021

Chronic Subdural Hematoma as a Complication of Cerebrospinal Fluid Leak During Revision Lumbar Spine Surgery: A Case Report and Review of the Literature.

HSS J 2020 Dec 5;16(Suppl 2):482-484. Epub 2019 Aug 5.

Department of Orthopaedic Surgery, Ferguson Lab for Orthopaedic Research, University of Pittsburgh Medical Center, E1643 Biomedical Science Tower, 200 Lothrop Street, Pittsburgh, PA 15213 USA.

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http://dx.doi.org/10.1007/s11420-019-09709-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7749911PMC
December 2020

Severe pulmonary injury leading to death during thoracic rod removal: a case report.

Eur Spine J 2020 12 12;29(Suppl 2):183-187. Epub 2020 Sep 12.

Division of Spinal Surgery, Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, 3741 Fifth Avenue, Suite 1010, Pittsburgh, PA, 15213, USA.

Purpose: Removal of hardware procedures following posterior spinal fusion is most commonly performed for hardware irritation without overt infection. It is imperative that surgeons realize that serious complications may arise from this procedure. The purpose of this report is to report a case of a pneumothorax that developed in a thoracolumbar removal of hardware case that resulted in a patient death.

Methods: Retrospective review of a patient's medical record and imaging.

Results: A 74-year-old patient with a history of T4-10 anterior discectomy and fusion with rib autograft and T4-L2 posterior fusion underwent a removal of hardware procedure for delayed surgical site infection. During the procedure, the tip of the bolt cutter jaw broke and entered the pulmonary cavity leading to a pneumothorax. The patient developed pneumonia 1 month postoperatively and passed away.

Conclusions: This case report highlights one of the rare but potential complications of spinal removal of hardware surgery. It is essential that surgeons are aware of the possibility of pulmonary complications during thoracolumbar removal of hardware cases so that they may fully counsel their patients on the potential risks.
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http://dx.doi.org/10.1007/s00586-020-06591-5DOI Listing
December 2020

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

Undisclosed Conflict of Interest Is Prevalent in Spine Literature.

Spine (Phila Pa 1976) 2020 Nov;45(21):1524-1529

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

Study Design: Cohort study.

Objective: The aim of this study was to determine the rate of accurate conflict of interest (COI) disclosure within three prominent subspecialty Spine journals during a 4-year period.

Summary Of Background Data: Industry-physician relationships are crucial for technological advancement in spine surgery but serve as a source of bias in biomedical research. The Open Payments Database (OPD) was established after 2010 to increase financial transparency.

Methods: All research articles published from 2014 to 2017 in Spine, The Spine Journal (TSJ), and the Journal of Neurosurgery: Spine (JNS) were reviewed in this study. In these articles, all author's COI statements were recorded. The OPD was queried for all author entries within the disclose period of the journal. Discrepancies between the author's self-reported COIs and the documented COIs from OPD were recorded.

Results: A total of 6816 articles meeting inclusion criteria between 2014 and 2017 in Spine, TSJ, and JNS with 39,869 contributing authors. Overall, 15.8% of all authors were found to have an OPD financial relationship. Of 2633 authors in Spine with financial disclosures, 77.1% had accurate financial disclosures; 42.5% and 41.0% of authors with financial relationships in the OPD had accurate financial disclosures in TSJ and JNS, respectively. The total value of undisclosed conflicts of interest between 2014 and 2017 was $421 million with $1.48 billion in accurate disclosures. Of undisclosed payments, 68.7% were <$1000 and only 7.2% were >$10,000. Undisclosed payments included $180 million in research funding and $188 million in royalties.

Conclusion: This study demonstrates that undisclosed COI is highly prevalent for authors in major Spine journals. This study indicates that there remains a need to standardize definitions and financial thresholds for significant COI as well as to shift the reporting burden for COI to journals who actively review potential COIs instead of relying on self-reporting.

Level Of Evidence: 3.
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http://dx.doi.org/10.1097/BRS.0000000000003589DOI Listing
November 2020

Assessing the biofidelity of in vitro biomechanical testing of the human cervical spine.

J Orthop Res 2020 Apr 25. Epub 2020 Apr 25.

Ferguson Lab for Orthopaedic Research, Department of Orthopaedic Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.

In vitro biomechanical studies of the osteoligamentous spine are widely used to characterize normal biomechanics, identify injury mechanisms, and assess the effects of degeneration and surgical instrumentation on spine mechanics. The objective of this study was to determine how well four standards in vitro loading paradigms replicate in vivo kinematics with regards to the instantaneous center of rotation and arthrokinematics in relation to disc deformation. In vivo data were previously collected from 20 asymptomatic participants (45.5 ± 5.8 years) who performed full range of motion neck flexion-extension (FE) within a biplane x-ray system. Intervertebral kinematics were determined with sub-millimeter precision using a validated model-based tracking process. Ten cadaveric spines (51.8 ± 7.3 years) were tested in FE within a robotic testing system. Each specimen was tested under four loading conditions: pure moment, axial loading, follower loading, and combined loading. The in vivo and in vitro bone motion data were directly compared. The average in vitro instant center of rotation was significantly more anterior in all four loading paradigms for all levels. In general, the anterior and posterior disc heights were larger in the in vitro models than in vivo. However, after adjusting for gender, the observed differences in disc height were not statistically significant. This data suggests that in vitro biomechanical testing alone may fail to replicate in vivo conditions, with significant implications for novel motion preservation devices such as cervical disc arthroplasty implants.
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http://dx.doi.org/10.1002/jor.24702DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7606317PMC
April 2020

Diagnosis and Management of Adverse Reactions to Metal Debris.

Oper Tech Orthop 2019 Sep 1;29(3). Epub 2019 Oct 1.

Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, Kaufmann Medical Building, 3471 Fifth Ave., Suite 1010, Pittsburgh, PA 15213.

Modern total hip arthroplasty implants have incorporated modularity into their designs, providing the benefits of intraoperative flexibility and the ability to exchange the femoral heads in the future if necessary. However, this feature has unfortunately predisposed patients to the effects of corrosion, potentially resulting in adverse local tissue reactions (ALTR) and even systemic effects. A thorough understanding of the science of corrosion is important for the treating surgeon so that they can understand the underlying pathology, quickly diagnose the condition of ALTR, and risk stratify their patients to determine the best method of treatment. Revision surgery is not always necessary in cases of trunnionosis or ALTR, but the results of revision surgery are generally favorable.
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http://dx.doi.org/10.1016/j.oto.2019.100732DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7158878PMC
September 2019

In vivo changes in adjacent segment kinematics after lumbar decompression and fusion.

J Biomech 2020 03 14;102:109515. Epub 2019 Nov 14.

Department of Orthopaedic Surgery, Orthopaedic Biodynamics Laboratory, University of Pittsburgh, Pittsburgh, USA; EMPA (Swiss Federal Laboratories for Materials Science and Research), Mechanical Systems Engineering (Lab 304), Duebendorf, Switzerland.

The pathogenesis of lumbar adjacent segment disease is thought to be secondary to altered biomechanics resulting from fusion. Direct in vivo evidence for altered biomechanics following lumbar fusion is lacking. This study's aim was to describe in vivo kinematics of the superior adjacent segment relative to the fused segment before and after lumbar fusion. This study analyzed seven patients with symptomatic lumbar degenerative spondylolisthesis (5 M, 2F; age 65 ± 5.1 years) using a biplane radiographic imaging system. Each subject performed two to three trials of continuous flexion of their torso according to established protocols. Synchronized biplane radiographs were acquired at 20 images per second one month before and six months after single-level fusion at L4-L5 or L5-S1, or two-level fusion at L3-L5 or L4-S1. A previously validated volumetric model-based tracking process was used to track the position and orientation of vertebrae in the radiographic images. Intervertebral flexion/extension and AP translation (slip) at the superior adjacent segment were calculated over the entire dynamic flexion activity. Skin-mounted surface markers were tracked using conventional motion analysis and used to determine torso flexion. Change in adjacent segment kinematics after fusion was determined at corresponding angles of dynamic torso flexion. Changes in adjacent segment motion varied across patients, however, all patients maintained or increased the amount of adjacent segment slip or intervertebral flexion/extension. No patients demonstrated both decreased adjacent segment slip and decreased rotation. This study suggests that short-term changes in kinematics at the superior adjacent segment after lumbar fusion appear to be patient-specific.
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http://dx.doi.org/10.1016/j.jbiomech.2019.109515DOI Listing
March 2020

Temporizing External Fixation vs Splinting Following Ankle Fracture Dislocation.

Foot Ankle Int 2020 02 9;41(2):177-182. Epub 2019 Oct 9.

Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, Kaufmann Medical Building, Pittsburgh, PA, USA.

Background: Closed reduction and splinting followed by outpatient management is standard of care for temporizing most ankle fractures. However, ankle fracture-dislocation potentially warrants a different approach based on the propensity for loss of reduction. The purpose of this study was to determine the rate of complications associated with closed reduction and splinting of unstable ankle fracture-dislocations. Further, we sought to determine the efficacy of immediate external fixation as an alternative to splinting in cases too swollen for acute operation.

Methods: This retrospective chart review analyzed all ankle-fracture dislocations that came through a large health care system from 2008 to 2018. Patients managed with acute open reduction internal fixation (ORIF) and open fractures were excluded. In patients managed late, the cohorts were divided into those temporized with closed reduction/splinting vs external fixation. Reduction quality and splint technique were additionally assessed in splinted patients. A total of 354 closed ankle fracture-dislocations were identified: 298 patients (84%) underwent ORIF within 48 hours and were excluded; 28 (15 female/13 male, average age 46.8 years) were placed in an external fixator and 28 (22 female/6 male, average age 57.2 years) were reduced, splinted, and discharged.

Results: At follow-up, 14 of the patients (50%) in the splint group developed loss of reduction and 5 of these patients (17.6%) developed anteromedial skin necrosis from skin tenting. None of the patients in the ex-fix group developed loss of reduction or skin necrosis. The rate of redislocation and the rate of development of skin necrosis was statistically higher in cases temporized with a splint versus an external fixator ( < .01 and = .05, respectively).

Conclusion: We found that in ankle fracture-dislocations not treated with acute ORIF, splint immobilization was associated with an increased risk of complications, including redislocation and skin necrosis, when compared to a temporizing external fixator.

Level Of Evidence: Level III, retrospective comparative study.
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http://dx.doi.org/10.1177/1071100719879431DOI Listing
February 2020

The role of computed tomographic scan in ongoing triage of operative hepatic trauma: A Western Trauma Association multicenter retrospective study.

J Trauma Acute Care Surg 2015 Dec;79(6):951-6; discussion 956

From the Division of Trauma and General Surgery (M.E.K., J.J.W., J.I.S., J.L.S.), Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania; Department of Surgery (S.S.S., K.L.K.), Community Regional Medical Center, University of California, San Francisco-Fresno Campus, Fresno, California; Division of Acute Care Surgery (R.A.K., R.A.W.), Department of Surgery, University of Texas Health Science Center at Houston, Houston, Texas; Division of General Surgery (E.A.E., S.M.L.), Department of Surgery, Medical University of South Carolina, Charleston, South Carolina; and Department of Surgery (M.M.C., G.M.), The Medical Center of Plano, Plano, Texas.

Background: A subset of patients explored for abdominal injury have persistent hepatic bleeding on postoperative computed tomography (CT) and/or angiography, either not identified or not manageable at initial laparotomy. To identify patients at risk for ongoing hemorrhage and guide triage to angiography, we investigated the relationship of early postoperative CT scan with outcomes in operative hepatic trauma.

Methods: This is a retrospective review of 528 patients with hepatic injury taken to laparotomy without imaging within 6 hours of arrival to six trauma centers from 2007 to 2013, coordinated through the Western Trauma Association multicenter trials group.

Results: A total of 528 patients were identified, with a mean age of 31 years, 82% male, and 37% blunt injury; mean (SD) Injury Severity Score (ISS) was 27 (16) and base deficit was -9 (6); in-hospital mortality was 26%. Seventy-three patients died during initial exploration. Of 455 early survivors, 123 (27%) had a postoperative contrast CT scan within 24 hours of laparotomy. CT patients had more common blunt injury, higher ISS, and lower base deficit than those who did not undergo CT. CT identified hepatic contrast extravasation or pseudoaneurysm in 10 patients (8%). Hepatic bleeding on CT was 83% sensitive and 75% specific (likelihood ratio, 3.3) for later positive angiography; negative CT finding was 96% sensitive and 83% specific (likelihood ratio, 5.7) for later negative or not performed angiography. Despite occurring in a more severely injured cohort, performance of early postoperative CT was associated with reduced mortality (odds ratio, 0.16) in multivariate analysis. Blunt mechanism was also a multivariate predictor of mortality (odds ratio, 3.0).

Conclusion: Early postoperative CT scan after laparotomy for hepatic trauma identifies clinically relevant ongoing bleeding and is sufficiently sensitive and specific to guide triage to angiography. Contrast CT should be considered in the management algorithm for hepatic trauma, particularly in the setting of blunt injury. Further study should identify optimal patient selection criteria and CT scan timing in this population.

Level Of Evidence: Care management/therapeutic study, level IV; epidemiologic/prognostic study, level III.
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http://dx.doi.org/10.1097/TA.0000000000000692DOI Listing
December 2015

Protection by enteral glutamine is mediated by intestinal epithelial cell peroxisome proliferator-activated receptor-γ during intestinal ischemia/reperfusion.

Shock 2015 Apr;43(4):327-33

*Department of Surgery, University of Texas Health Science Center at Houston, Houston, Texas; and †Shock Trauma Center, University of Maryland School of Medicine, Baltimore, Maryland.

We have demonstrated that enteral glutamine provides protection to the postischemic gut, and that peroxisome proliferator-activated receptor-γ (PPARγ) plays a role in this protection. Using Cre/lox technology to generate an intestinal epithelial cell (IEC)-specific PPARγ null mouse model, we now investigated the contribution of IEC PPARγ to glutamine's local and distant organ-protective effects. These mice exhibited absence of expression of PPARγ in the intestine but normal PPARγ expression in other tissues. After 1 h of intestinal ischemia under isoflurane anesthesia, wild-type and null mice received enteral glutamine (60 mM) or vehicle followed by 6 h of reperfusion or 7 days in survival experiments and compared with shams. Small intestine, liver, and lungs were analyzed for injury and inflammatory parameters. Glutamine provided significant protection against gut injury and inflammation, with similar protection in the lung and liver. Changes in systemic tumor necrosis factor-α reflected those seen in the injured organs. Importantly, mice lacking IEC PPARγ had worsened injury and inflammation, and glutamine lost its protective effects in the gut and lung. The survival benefit found in glutamine-treated wild-type mice was not observed in null mice. Using an IEC-targeted loss-of-function approach, these studies provide the first in vivo confirmation in native small intestine and lung that PPARγ is responsible for the protective effects of enteral glutamine in reducing intestinal and lung injury and inflammation and improving survival. These data suggest that early enteral glutamine may be a potential therapeutic modality to reduce shock-induced gut dysfunction and subsequent distant organ injury.
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http://dx.doi.org/10.1097/SHK.0000000000000297DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4359662PMC
April 2015