Publications by authors named "Robert Gaines"

46 Publications

A paleosol record of the evolution of Cr redox cycling and evidence for an increase in atmospheric oxygen during the Neoproterozoic.

Geobiology 2019 11 22;17(6):579-593. Epub 2019 Aug 22.

Department of Geology and Geophysics, Yale University, New Haven, CT, USA.

Atmospheric oxygen levels control the oxidative side of key biogeochemical cycles and place limits on the development of high-energy metabolisms. Understanding Earth's oxygenation is thus critical to developing a clearer picture of Earth's long-term evolution. However, there is currently vigorous debate about even basic aspects of the timing and pattern of the rise of oxygen. Chemical weathering in the terrestrial environment occurs in contact with the atmosphere, making paleosols potentially ideal archives to track the history of atmospheric O levels. Here we present stable chromium isotope data from multiple paleosols that offer snapshots of Earth surface conditions over the last three billion years. The results indicate a secular shift in the oxidative capacity of Earth's surface in the Neoproterozoic and suggest low atmospheric oxygen levels (<1% PAL pO ) through the majority of Earth's history. The paleosol record also shows that localized Cr oxidation may have begun as early as the Archean, but efficient, modern-like transport of hexavalent Cr under an O -rich atmosphere did not become common until the Neoproterozoic.
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http://dx.doi.org/10.1111/gbi.12360DOI Listing
November 2019

The Qingjiang biota-A Burgess Shale-type fossil Lagerstätte from the early Cambrian of South China.

Science 2019 03 21;363(6433):1338-1342. Epub 2019 Mar 21.

State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environment, Department of Geology, Northwest University, Xi'an 710069, PR China.

Burgess Shale-type fossil Lagerstätten provide the best evidence for deciphering the biotic patterns and magnitude of the Cambrian explosion. Here, we report a Lagerstätte from South China, the Qingjiang biota (~518 million years old), which is dominated by soft-bodied taxa from a distal shelf setting. The Qingjiang biota is distinguished by pristine carbonaceous preservation of labile organic features, a very high proportion of new taxa (~53%), and preliminary taxonomic diversity that suggests it could rival the Chengjiang and Burgess Shale biotas. Defining aspects of the Qingjiang biota include a high abundance of cnidarians, including both medusoid and polypoid forms; new taxa resembling extant kinorhynchs; and abundant larval or juvenile forms. This distinctive composition holds promise for providing insights into the evolution of Cambrian ecosystems across environmental gradients.
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http://dx.doi.org/10.1126/science.aau8800DOI Listing
March 2019

Letter to the Editor concerning: Crawford 3rd CH, Larson N, Gates M, et al Spine Deformity 5(2017):284-302.

Spine Deform 2018 01;6(1):97

Columbia Orthopaedic Group, Columbia, MO, USA.

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http://dx.doi.org/10.1016/j.jspd.2017.10.006DOI Listing
January 2018

Preventing Seal Leak During Negative Pressure Wound Therapy Near External Fixators: A Technical Tip.

J Orthop Trauma 2017 Mar;31(3):e101-e102

Department of Orthopaedic Surgery, Naval Medical Center Portsmouth, Portsmouth, VA.

Negative pressure wound therapy is an effective tool for the treatment of open wounds. Occasionally these wounds are associated with injuries or procedures that require treatment with an external fixator. This article shows how a simple, inexpensive, and commercially available product can be used to prevent loss of suction around external fixator pins within the negative pressure wound treatment area.
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http://dx.doi.org/10.1097/BOT.0000000000000709DOI Listing
March 2017

Dead Space Management After Orthopaedic Trauma: Tips, Tricks, and Pitfalls.

J Orthop Trauma 2016 Feb;30(2):64-70

*Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY;†Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, Covenant Health System, Lubbock, TX; and‡Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, Harborview Medical Center, Seattle, WA.

Unlabelled: Dead space is defined as the residual tissue void after tissue loss. This may occur due to tissue necrosis after high-energy trauma, infection, or surgical debridement of nonviable tissue. This review provides an update on the state of the art and recent advances in the management of osseous and soft tissue defects. Specifically, our focus will be on the initial dead space assessment, provisional management of osseous and soft tissue defects, techniques for definitive reconstruction, and dead space management in the setting of infection.

Level Of Evidence: Therapeutic Level V. See Instructions for Authors for a complete description of levels of evidence.
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http://dx.doi.org/10.1097/BOT.0000000000000454DOI Listing
February 2016

"Bone-οn-Bone" surgical reconstruction of moderate severity, flexible single curve adolescent idiopathic scoliosis: continuing improvements of the technique and results in three scoliosis centers after almost twenty years of use.

Scoliosis 2015 24;10:10. Epub 2015 Mar 24.

Orthopaedic and Rehabilitation University Hospital Collegium Medicum Jagiellonian University, Zakopane, Poland.

The "bone-on-bone" reconstruction for adolescent idiopathic scoliosis is reviewed in this article. Extensive use over the past 18 years has identified it's functional benefits outstanding clinical results, and very limited complications. This is an extensive update of it's application, since it's introduction, 18 years ago.
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http://dx.doi.org/10.1186/s13013-015-0032-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4440536PMC
May 2015

The "slide technique": an improvement on the "funnel technique" for safe pedicle screw placement in the thoracic spine.

Eur Spine J 2014 Jul 14;23 Suppl 4:S452-6. Epub 2014 May 14.

Department of Pediatric Orthopaedics, Université Pierre et Marie Curie Paris 6, Armand Trousseau Hospital, 26 avenue du Dr Arnold Netter, 75571, Paris Cedex 12, France,

Study Design: Technical note.

Objectives: To report and describe a new free-hand technique for pedicle screw placement in the thoracic spine especially in severe deformities. Because of distortion of anatomic landmarks scoliosis, this free-hand placement technique based on pedicle access through the decancelled transverse process is a safe procedure.

Methods: Transverse process is widely exposed and its posterior cortex is decorticated. The cancellous bone content of the transverse process is completely removed using a small curette. Bone wax is applied to avoid local bleeding and then the decancelled transverse process is inspected. The entry of the pedicle is then easily identified by the presence of remaining cancellous bone. A pedicular probe is then inserted and gently advanced. During pedicle probe insertion, the cortex of the anterior aspect of transverse process and the lateral margin of the pedicle act as a "slide" to permit safe insertion of the instrument.

Results: In our experience, no patient required additional procedures for screw revision, and no neurologic deficit occurred stemming from malpositioning of pedicle screws. The key point of the "slide technique" is to use the cortex of the anterior aspect of transverse process and the lateral margin of the pedicle as a "slide" to permit correct probe positioning during pedicle probe insertion.

Conclusions: This technique is very close to the "funnel technique". The "funnel" and then the "slide" technique are mostly useful in complex spinal deformities as in neuromuscular patients. The "slide technique" is a safe, effective and cost-effective technique for pedicle screw placement in the thoracic spine especially in severe deformities.

Level Of Evidence: IV.
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http://dx.doi.org/10.1007/s00586-014-3342-7DOI Listing
July 2014

Characterization and surgical outcomes of proximal junctional failure in surgically treated patients with adult spinal deformity.

Spine (Phila Pa 1976) 2014 May;39(10):E607-14

*National Hospital Organization Murayama Medical Center, Tokyo †Scott and White Clinic, Temple, TX ‡Columbia Spine Center and Orthopaedic Group, Columbia, MO §Hospital for Special Surgery, New York, NY ¶Johns Hopkins University, Baltimore, MD; and Complex Spine Study Group, Leesburg VA, US.

Study Design: Retrospective case series of surgically treated patients with adult spine deformity (ASD).

Objective: To report the incidence of proximal junctional failure (PJF), characterize PJF and evaluate the outcome of revision surgery for PJF. A modified classification is also proposed.

Summary Of Background Data: Although recent reports have shown the catastrophic results of PJF, few reports have shown the incidence, characteristics, and clinical outcomes of PJF in ASD.

Methods: This retrospective analysis reviewed data entered prospectively into a multicenter database. Surgically treated patients with ASD with a minimum 2-year follow-up were included. PJF was defined as any type of symptomatic proximal junctional kyphosis (PJK) requiring surgery. On the basis of our previous classification, the following modified PJK classification was established: grade A, proximal junctional increase of 10° to 19°; grade B, 20° to 29°; and grade C, 30° or more. Three types of PJK were also defined: ligamentous failure (type 1), bone failure (type 2), and implant/bone interface failure (type 3). An additional criterion was added for the presence or absence of spondylolisthesis above the upper instrumentation vertebra (UIV).

Results: PJF developed in 23 of the 1668 patients with ASD. The incidence of PJF was 1.4%. The mean age was 62.3 ± 7.9 years, and the mean follow-up was 4.0 ± 2.3 years. Seventeen patients had undergone prior surgical procedures. Six patients had UIV above T8, and 17 had UIV below T9. Six patients had associated spondylolisthesis above the UIV (PJF-S), whereas 17 patients did not (PJF-N). The radiographical data show a significant difference in the preoperative sagittal vertical axis between the PJF-S and PJF-N groups, whereas no significant difference was observed in the preoperative sagittal parameters (5.2 ± 3.9 cm vs. 11.4 ± 6.0 cm, P = 0.04). The most common type of PJF was type 2N. The PJF symptoms consisted of intolerable pain (n = 17), neurological deficits (n = 6), and progressive trunk deformity (n = 1). Eleven patients had additional PJK/PJF and 9 required additional revision surgical procedures.

Conclusion: The incidence of PJF among surgically treated patients with ASD was 1.4%. The most common type of PJF was 2N. Preoperative large sagittal vertical axis change and large amount of correction was a causative factor for spondylolisthesis above the UIV. After the revision surgery, further PJF was a commonly occurred event.
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http://dx.doi.org/10.1097/BRS.0000000000000266DOI Listing
May 2014

A new phyllopod bed-like assemblage from the Burgess Shale of the Canadian Rockies.

Nat Commun 2014 ;5:3210

Department of Earth Sciences, Uppsala University, Villavägen 16, 75236 Uppsala, Sweden.

Burgess Shale-type fossil assemblages provide the best evidence of the 'Cambrian explosion'. Here we report the discovery of an extraordinary new soft-bodied fauna from the Burgess Shale. Despite its proximity (ca. 40 km) to Walcott's original locality, the Marble Canyon fossil assemblage is distinct, and offers new insights into the initial diversification of metazoans, their early morphological disparity, and the geographic ranges and longevity of many Cambrian taxa. The arthropod-dominated assemblage is remarkable for its high density and diversity of soft-bodied fossils, as well as for its large proportion of new species (22% of total diversity) and for the preservation of hitherto unreported anatomical features, including in the chordate Metaspriggina and the arthropod Mollisonia. The presence of the stem arthropods Misszhouia and Primicaris, previously known only from the early Cambrian of China, suggests that the palaeogeographic ranges and longevity of Burgess Shale taxa may be underestimated.
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http://dx.doi.org/10.1038/ncomms4210DOI Listing
October 2015

Comparison of insertional trauma between suprapatellar and infrapatellar portals for tibial nailing.

Orthopedics 2013 Sep;36(9):e1155-8

The purpose of this study was to determine differences in insertional articular trauma in infrapatellar tibial portal and suprapatellar portal intramedullary tibial nail insertion techniques. A cadaveric study was performed on 10 matched pairs of fresh-frozen adult cadaver lower extremities with intact extensor mechanisms. Two study groups with 10 limbs each were created: left lower limbs were treated with a standard medial parapatellar nailing portal and right lower limbs were treated with a suprapatellar tibial nailing portal. Start points were created under fluoroscopic guidance in anteroposterior and mediolateral planes. A start wire was placed and opening reaming was performed on the specimens using instrumentation specific to the nailing portal. Specimens were then dissected by medial parapatellar arthrotomy, revealing the intra-articular condition of the knee structures. The border of the tibial entry reamer hole was measured to the anterior horns of the menisci, anterior cruciate ligament root, and intermeniscal ligament using a digital caliper accurate to 0.02 mm. The structure was considered damaged if the structure was obviously damaged on visual inspection or if a measurement was less than 1 mm. Impact to intra-articular structures was numerically lower in the suprapatellar group (2/10) compared with the infrapatellar group (4/10), but the difference was not statistically significant between the 2 groups (P=.629). The suprapatellar portal approach to the tibial start point demonstrated a lower overall incidence of damage to intra-articular structures, but no significant statistical difference existed between the 2 treatment groups.
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http://dx.doi.org/10.3928/01477447-20130821-17DOI Listing
September 2013

A novel technique for ligamentous reconstruction of the sternoclavicular joint.

J Orthop Trauma 2014 Mar;28(3):e65-9

*Orthopaedic Trauma Service, Naval Medical Center, Portsmouth, VA; and †Division of Orthopaedic Trauma, Department of Orthopeadic Surgery, University of Medicine and Dentistry of New Jersey, Newark, NJ.

Summary: The technique presented is a departure from previous attempts to standardize the treatment of sternoclavicular dislocations. It offers stability without requiring extra dissection around vital intrathoracic structures and greatly decreases the risk of migration of the implant used for fixation.
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http://dx.doi.org/10.1097/BOT.0b013e31829aa9c5DOI Listing
March 2014

Pubic symphysis diastasis with urinary incontinence: collaborative surgical management.

Int Urogynecol J 2013 Oct 15;24(10):1757-9. Epub 2013 May 15.

Department of Obstetrics & Gynecology, Naval Medical Center Portsmouth, 620 John Paul Jones Cir, Portsmouth, VA, 23708, USA,

Pubic symphysis diastasis during obstetric delivery occurs rarely. Symptoms usually respond to conservative management. A nulliparous 39-year-old delivered spontaneously with an audible pop noted. Pubic symphysis diastasis of 4.6 cm was diagnosed on pelvic X-ray. She developed severe pain with ambulation and stress urinary incontinence. After neither of these symptoms improved significantly in response to conservative management, the patient underwent open reduction internal fixation with plating of her pubic symphysis, and bladder neck sling placement using autologous rectus fascia. Postoperatively she experienced urinary retention, which resolved with continuous bladder drainage for 1 week. Both her urinary incontinence and pain resolved, and she had resumed normal activities 3 months following her surgery. Pubic symphysis diastasis is a rare obstetric complication with a paucity of literature to guide its management. A coordinated multidisciplinary approach to management is necessary when multiple organ systems are involved.
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http://dx.doi.org/10.1007/s00192-013-2120-0DOI Listing
October 2013

Reprioritization of research for combat casualty care.

J Am Acad Orthop Surg 2012 ;20 Suppl 1:S99-102

Department of Orthopaedics and Rehabilitation, San Antonio Military Medical Center, Fort Sam Houston, TX, USA.

Since the beginning of the conflicts in Iraq and Afghanistan more than a decade ago, much has been learned with regard to combat casualty care. Although progress has been significant, knowledge gaps still exist. The seventh Extremity War Injuries symposium, held in January 2012, reviewed the current state of knowledge and defined knowledge gaps in acute care, reconstructive care, and rehabilitative care in order to provide policymakers information on the areas in which research funding would be the most beneficial.
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http://dx.doi.org/10.5435/JAAOS-20-08-S99DOI Listing
September 2012

Evolution of orthopaedic reconstructive care.

J Am Acad Orthop Surg 2012 ;20 Suppl 1:S74-9

Department of Orthopaedics and Rehabilitation, Walter Reed National Military Medical Center, USA.

The patterns and severity of injury sustained by service members have continuously evolved over the past 10 years of combat in Iraq and Afghanistan. The 2010 surge of combat troops into Afghanistan, combined with a transition to counterinsurgency tactics with an emphasis on dismounted operations, resulted in increased exposure of US service members to improvised explosive devices and a new pattern of injury termed dismounted complex blast injury. This constellation of injuries typically includes multiple extremity injuries, high bilateral transfemoral amputations, amputated or mangled upper extremities, open pelvis fractures, and injury to the perineal and/or genital regions. These polytraumatized patients frequently present with head, abdominal, and genitourinary injuries, as well. Traditional methods of reconstruction must be optimized because tissue availability may be limited.
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http://dx.doi.org/10.5435/JAAOS-20-08-S74DOI Listing
September 2012

Fire in the operating room: a previously unreported ignition source.

Am J Orthop (Belle Mead NJ) 2012 Aug;41(8):378-9

Department of Orthopaedic Surgery, Naval Medical Center Portsmouth, Portsmouth, Virginia 23708-2197, USA.

Surgical fires are a serious threat to the patient and surgical team in the operating room. Burns have been reported at, and distant to, the operating site, as well as within the body. The essential point to remember is that at least 1 arm of the fire triangle-an oxidizer, fuel, and an ignition source-must be completely controlled to prevent an intraoperative fire. Here we give the example of a pulse lavage system as a possible ignition source.
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August 2012

Parallel plating for a sternomanubrial dislocation.

Orthopedics 2012 Aug;35(8):e1276-8

Orthopaedic Trauma Service, United States Navy, Naval Medical Center Portsmouth, VA, USA.

Sternomanubrial dislocations are rare injuries. Although few cases of this injury have been reported in the literature, the etiology has varied widely: trampoline injury, seizures, falls from height, sporting injuries, gradual deformities from spine fractures, and motor vehicle collisions. This injury has been classified into 2 types: in type I, the sternal body is displaced posteriorly to the manubrium, and in the more common type II, the sternal body is displaced anteriorly. The sternomanubrial joint is an amphiarthroidal joint that bears hyaline cartilage on both surfaces connected by a fibrocartilage meniscus. It serves a protective role to vital thoracic structures and is an anterior stabilizing strut to the thorax, assisting the thoracic spine in upright stability. It is important to not ignore type I dislocations because posterior sternum displacement is a harbinger of injury to the pulmonary tree, heart, and esophagus. Chronic instability at this joint can lead to dyspnea and dysphasia due to sternum displacement. In the right scenario, type II injuries are occasionally treated conservatively with palliative treatment until the sternum heals with malformation. This article describes the case of a 20-year-old man who was treated surgically for symptomatic type II sternomanubrial dislocation with dual anterior locked plating. Locked plating gives the benefit of unicortical fixation, with the screws and plate acting as a unit to resist motion. Screw pullout and failure is less common, and the construct is more resistant for this application. The patient returned to full participation in activities of daily living and military duty 4 months postoperatively.
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http://dx.doi.org/10.3928/01477447-20120725-34DOI Listing
August 2012

Treatment of atrophic diaphyseal humeral nonunions with compressive locked plating and augmented with an intramedullary strut allograft.

J Orthop Trauma 2013 Feb;27(2):77-81

Department of Shoulder and Elbow Surgery, Florida Orthopaedic Institute, Tampa, FL 33637, USA.

Objective: The aim of this study was to evaluate the effectiveness of thorough debridement and locked compression plating augmented with an intramedullary fibular allograft for the treatment of atrophic diaphyseal humeral nonunions.

Design: The study involved a level 4 retrospective case series.

Setting: This study was conducted at a level 1 university trauma center.

Patients: Twenty patients with painful atrophic nonunions of the humeral diaphysis were examined.

Intervention: This involved a thorough debridement and locked compression plating augmented with an intramedullary fibular allograft.

Main Outcome Measures: These were union rate, shoulder range of motion, visual analog scale (VAS) pain, VAS function, patient satisfaction, and American Shoulder and Elbow Surgeons score at latest follow-up.

Methods: Clinical and radiographic examinations were performed preoperatively and postoperatively. VAS pain and function scores were collected preoperatively and postoperatively. Patient satisfaction and ASES scores were recorded at the time of the most recent follow-up.

Results: : Bony union was achieved in 19 of 20 patients (95%). The patients demonstrated an average improvement in forward elevation from 65 to 144° (P = 0.001), abduction from 48 to 133° (P < 0.001), external rotation from 34 to 70° (P = 0.05), and internal rotation from S1 to T12 (P = 0.025). VAS pain scores improved from 6.05 to 1.88 (P = 0.032). VAS function scores improved from 2.06 to 7.75 (P = 0.003). The average postoperative ASES score was 76, and the average patient satisfaction was rated 9.3/10.

Conclusions: Atrophic nonunions of the humerus can be successfully treated with debridement of the nonunion, coupled with the use of a fibular allograft and locked compression plating. This technique leads to predictable healing without the morbidity associated with autograft.

Level Of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
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http://dx.doi.org/10.1097/BOT.0b013e31825360faDOI Listing
February 2013

Formation of the 'Great Unconformity' as a trigger for the Cambrian explosion.

Nature 2012 Apr 18;484(7394):363-6. Epub 2012 Apr 18.

Department of Geoscience, University of Wisconsin, Madison, Wisconsin 53706, USA.

The transition between the Proterozoic and Phanerozoic eons, beginning 542 million years (Myr) ago, is distinguished by the diversification of multicellular animals and by their acquisition of mineralized skeletons during the Cambrian period. Considerable progress has been made in documenting and more precisely correlating biotic patterns in the Neoproterozoic-Cambrian fossil record with geochemical and physical environmental perturbations, but the mechanisms responsible for those perturbations remain uncertain. Here we use new stratigraphic and geochemical data to show that early Palaeozoic marine sediments deposited approximately 540-480 Myr ago record both an expansion in the area of shallow epicontinental seas and anomalous patterns of chemical sedimentation that are indicative of increased oceanic alkalinity and enhanced chemical weathering of continental crust. These geochemical conditions were caused by a protracted period of widespread continental denudation during the Neoproterozoic followed by extensive physical reworking of soil, regolith and basement rock during the first continental-scale marine transgression of the Phanerozoic. The resultant globally occurring stratigraphic surface, which in most regions separates continental crystalline basement rock from much younger Cambrian shallow marine sedimentary deposits, is known as the Great Unconformity. Although Darwin and others have interpreted this widespread hiatus in sedimentation on the continents as a failure of the geologic record, this palaeogeomorphic surface represents a unique physical environmental boundary condition that affected seawater chemistry during a time of profound expansion of shallow marine habitats. Thus, the formation of the Great Unconformity may have been an environmental trigger for the evolution of biomineralization and the 'Cambrian explosion' of ecologic and taxonomic diversity following the Neoproterozoic emergence of animals.
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http://dx.doi.org/10.1038/nature10969DOI Listing
April 2012

Management of contaminated open fractures: a comparison of two types of irrigation in a porcine model.

J Trauma Acute Care Surg 2012 Mar;72(3):733-6

Department of Bone and Joint Sports Medicine, Naval Medical Center Portsmouth, Portsmouth, Virginia 23708, USA.

Background: Treatment of open fractures demands rapid intervention consisting of intravenous antibiotics, aggressive debridement, fracture immobilization, and soft tissue management including additional debridements and soft tissue coverage. Despite this approach, infection, particularly osteomyelitis, after open fracture continues to be a source of significant morbidity. Recent literature has provided several studies that performed clinical trials in superficial wounds. These investigations compared sterile solutions with tap water for wound decontamination. The results suggest that tap water washouts are cost-effective for these specific wounds.

Material: An established protocol using sterile porcine hind limb tibias, as reported by Bhandari et al., was applied with modification. There were then 15 specimens and 5 controls (no irrigation) for each condition. The conditions were potable water and sterile water. A representative bacterium of gram-positive, Staphylococcus aureus, or gram-negative, Escherichia coli, acted as the contaminant. Sectioned, sterile porcine hind limb tibias were inoculated with 1 mL of a known concentration (1 × 10(10)) of bacterium and incubated. Each specimen was then irrigated, with bulb irrigation at a standardized distance of 15 cm, with 500 mL of irrigation. The specimen, along with 0.5 mL of wash (irrigant collected after it was placed over the specimen), was placed in 5 mL of Brain Heart Infusion broth. All specimens were incubated in this broth at 37°C for 2 hours. At 2 hours, a 100-μL supernatant was plated on blood agar plates and incubated for 24 hours. Colony counts for each specimen and controls were then performed.

Results: The number of colony forming units (CFUs) for each type of bacterium was different. The average CFUs from bone samples contaminated with E. coli was 5.18 × 10(8) after irrigation with sterile water and 6.24 × 10(8) after irrigation with tap water. The average CFUs from bone samples contaminated with S. aureus was 18 × 10(6) after irrigation with sterile water and 12 × 10(6) after irrigation with tap water. The average CFUs from the irrigation samples from E. coli contamination treated with sterile water was 1.3 × 10(6) and the CFUs from E. coli contamination treated with tap water was 2.2 × 10(6). The average CFUs from the irrigation samples from S. aureus contamination treated with sterile water was 1.57 × 10(6) and the CFUs from S. aureus contamination treated with tap water was 1.56 × 10(6).

Conclusion: There was no significant difference between the CFUs for the sterile and potable water (p = 0.201) for each bacterium (p = 0.871).
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http://dx.doi.org/10.1097/TA.0b013e318239caafDOI Listing
March 2012

Mechanism for Burgess Shale-type preservation.

Proc Natl Acad Sci U S A 2012 Apr 5;109(14):5180-4. Epub 2012 Mar 5.

Geology Department, Pomona College, Claremont, CA 91711, USA.

Exceptionally preserved fossil biotas of the Burgess Shale and a handful of other similar Cambrian deposits provide rare but critical insights into the early diversification of animals. The extraordinary preservation of labile tissues in these geographically widespread but temporally restricted soft-bodied fossil assemblages has remained enigmatic since Walcott's initial discovery in 1909. Here, we demonstrate the mechanism of Burgess Shale-type preservation using sedimentologic and geochemical data from the Chengjiang, Burgess Shale, and five other principal Burgess Shale-type deposits. Sulfur isotope evidence from sedimentary pyrites reveals that the exquisite fossilization of organic remains as carbonaceous compressions resulted from early inhibition of microbial activity in the sediments by means of oxidant deprivation. Low sulfate concentrations in the global ocean and low-oxygen bottom water conditions at the sites of deposition resulted in reduced oxidant availability. Subsequently, rapid entombment of fossils in fine-grained sediments and early sealing of sediments by pervasive carbonate cements at bed tops restricted oxidant flux into the sediments. A permeability barrier, provided by bed-capping cements that were emplaced at the seafloor, is a feature that is shared among Burgess Shale-type deposits, and resulted from the unusually high alkalinity of Cambrian oceans. Thus, Burgess Shale-type preservation of soft-bodied fossil assemblages worldwide was promoted by unique aspects of early Paleozoic seawater chemistry that strongly impacted sediment diagenesis, providing a fundamentally unique record of the immediate aftermath of the "Cambrian explosion."
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http://dx.doi.org/10.1073/pnas.1111784109DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3325652PMC
April 2012

Use of an "antibiotic plate" for infected periprosthetic fracture in total hip arthroplasty.

J Orthop Trauma 2012 Mar;26(3):e18-23

Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, NJ 07103, USA.

Periprosthetic fracture and infection are dreaded complications after total hip arthroplasty. We present the case of a 50-year-old man who suffered an early postoperative Vancouver B1 periprosthetic fracture, which was further complicated by concurrent infection after open reduction and internal fixation. We report the novel use of an antibiotic-impregnated cement coated locking plate during the staged treatment of concomitant periprosthetic fracture and chronic total hip arthroplasty infection. At 1-year follow-up, the patient is pain free and ambulating independently with full range of motion.
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http://dx.doi.org/10.1097/BOT.0b013e318216dd60DOI Listing
March 2012

Single-stage total hip arthroplasty and fracture fixation for a both column acetabular fracture in type I osteogenesis imperfecta.

Injury 2011 Oct 1;42(10):1184-7. Epub 2011 Jun 1.

Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, 90 Bergen Street, Newark, NJ 07103, United States.

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http://dx.doi.org/10.1016/j.injury.2011.05.008DOI Listing
October 2011

Short segment bone-on-bone instrumentation for adolescent idiopathic scoliosis: a mean follow-up of six years.

Spine (Phila Pa 1976) 2011 Jun;36(14):1123-30

Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan.

Study Design: Prospective case series.

Objective: To evaluate the clinical and radiologic outcomes of short segment anterior scoliosis surgery with bone-on-bone apposition using a dual screw, dual rod system.

Summary Of Background Data: Posterior segmental fixation for correction of AIS involves instrumentation of all the vertebrae included in the major curve. Our short segment anterior technique produces similar results by fusion of fewer levels.

Methods: Forty-five patients operated between 1996 and 2004. Twenty-eight thoracic (Lenke 1) and 17 thoracolumbar (Lenke 5). The mean age was 19 years, 87% were females, and the mean follow-up was 72 months (range 28-121 months). We operated on curves less than 85° with "total discectomy," bone-on-bone apposition, and dual-screw, dual-rod fixation.

Results: A mean of five vertebrae (four discs) were instrumented, with a mean operative time of 360 minutes, blood loss of 877 mL and a hospital stay of 9.1 day. Lenke 1. The main preop thoracic curve was 52.5°, final postop curve 27.9°, by fusing five vertebrae, four discs. A spontaneous improvement of 47.5% of the lumbar compensatory curve was seen. The lower tilt angle corrected from 20.9° to 11°. Lenke 5. The preoperative thoracolumbar major curve corrected from 50.5° to 18.3° (final) with fusion of four vertebrae, three discs. A spontaneous improvement of 37.4% occurred in the thoracic compensatory curve. The preop tilt angle improved from 27.7° to 8.3°.The sagittal and coronal balance was restored in all the patients. There were no neurologic, vascular, pulmonary, or implant-related complications. Union occurred within 3 months. All the patients returned to an unrestricted lifestyle within 4 months.

Conclusion: We report good results after surgical correction using our short segment bone-on-bone technique. Improvements were noted and maintained, over a 6-year period.
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http://dx.doi.org/10.1097/BRS.0b013e3181f9a07aDOI Listing
June 2011

Acute compartment syndrome of the foot following fixation of a pilon variant ankle fracture.

Orthopedics 2010 Dec 1;33(12):926. Epub 2010 Dec 1.

Bone and Joint/Sports Medicine Institute, Naval Medical Center Portsmouth, Virginia, USA.

Acute traumatic compartment syndrome of the foot is a serious potential complication after fractures, crush injuries, or reperfusion injury after vascular repair. Foot compartment syndrome in association with injuries to the ankle is rare. This article presents a case of acute compartment syndrome of the foot following open reduction and internal fixation of an ankle fracture. A 16-year-old girl presented after sustaining a left ankle injury. Radiographs demonstrated a length-stable posterior and lateral malleolar ankle fracture. Initial treatment consisted of a bulky splint and crutches pending the improvement of her swelling. Over the course of a week, the soft tissue environment of the distal lower extremity improved, and the patient underwent open reduction and internal fixation of both her fibula and distal tibia through 2 approaches. Approximately 2 hours from the completion of surgery, the patient reported worsening pain over the medial aspect of her foot and into her calcaneus. Physical examination of the foot demonstrated a swollen and tense abductor hallicus and heel pad. Posterior tibial and dorsalis pedis pulses were palpable and her sensation was intact throughout her foot. Emergently, fasciotomy of both compartments was performed through a medial incision. Postoperatively, the patient reported immediate pain relief. At 18-month follow-up, she reported no pain and had returned to all of her preinjury athletic activities.
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http://dx.doi.org/10.3928/01477447-20101021-33DOI Listing
December 2010

Delayed presentation of bladder entrapment secondary to nonoperative treatment of a lateral compression pelvic fracture.

J Orthop Trauma 2010 May;24(5):e44-8

Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY 10003, USA.

Entrapment of the bladder secondary to pelvic fracture is infrequently described in the literature. Entrapment has most commonly been found to occur through the actions of internal or external fixation. This case report presents bladder entrapment that was not detected until the patient developed genitourinary symptoms and dyspareunia 8 months after nonoperative treatment of a stable lateral compression pelvic fracture.
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http://dx.doi.org/10.1097/BOT.0b013e3181a9ee1dDOI Listing
May 2010

Closed reduction of a dislocated total hip arthroplasty with a constrained acetabular component.

Am J Orthop (Belle Mead NJ) 2009 Oct;38(10):523-5

Department of Orthopedic Surgery, Bone and Joint/Sports Medicine Institute, Naval Medical Center Portsmouth, Portsmouth, VA 23708, USA.

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October 2009

Injury to the tarsometatarsal joint complex during fixation of Lisfranc fracture dislocations: an anatomic study.

J Trauma 2009 Apr;66(4):1125-8

Department of Orthopaedic Surgery, Bone and Joint Sports Medicine Institute, Naval Medical Center Portsmouth, Portsmouth, Virginia, USA.

Background: The cause of posttraumatic arthritis in Lisfranc injuries is argued in the literature. The purpose of this study was to determine whether the involved joint surface area increased with repositioning of the guidewire before screw placement.

Materials: Nine matched pairs of cadaveric feet were disarticulated at the tibiotalar joint. Under fluoroscopic guidance, cannulated screws were placed over guidewires after a single pass across the joint for right feet and two passes across the joint for left feet. Specimens were disarticulated through the midfoot, and the digital images of the joint surface were evaluated for joint surface area and the surface area of cartilaginous damage resulting from screw placement.

Results: Mean injury area for the first metatarsal (MT1) was 0.106 cm2 for one pass and 0.168 cm2 for two passes of the guidewire before screw advancement (p = 0.003) The mean injury area for the second metatarsal (MT2) was 0.123 and 0.178 cm2 for one and two passes, respectively (p = 0.018). Four of nine (44%) of the left foot specimens (2 passes of the guidewire) sustained fractures across the MT2 base and three of those specimens also revealed fractures on the middle cuneiform side of the joint (33%).

Conclusion: Changing the placement of the guidewire across the midfoot significantly increased the joint surface affected by screw placement. Screws placed plantar to the midline of the joint increased the risk of fracture on both sides of the tarsometatarsal complex.
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http://dx.doi.org/10.1097/TA.0b013e318176c563DOI Listing
April 2009

Delayed presentation of compartment syndrome of the proximal lower extremity after low-energy trauma in patients taking warfarin.

Am J Orthop (Belle Mead NJ) 2008 Dec;37(12):E201-4

Department of Orthopaedic Surgery, Bone and Joint/Sports Medicine Institute, Naval Medical Center, 27 Effingham St, Portsmouth, VA 23708, USA.

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December 2008

Patellar tendon repair with suture anchors using a combined suture technique of a Krackow-Bunnell weave.

J Orthop Trauma 2009 Jan;23(1):68-71

Department of Orthopaedic Surgery, Bone/Joint Sports Medicine Institute, 620 John Paul Jones Circle, Portsmouth, VA 23708-2197, USA.

Suture repair of the ruptured patellar tendon is the treatment of choice for patients requiring operative management. This standard technique includes fixation through transosseous tunnels in the patella. The use of suture anchor fixation has several advantages over the standard approach, including less dissection, decreased surgical time, more accurate suture placement, and a low-profile construct. Additionally, the pullout strength of suture anchors warrants consideration of this technique in these repairs. This article describes using suture anchors for repair of the acute ruptured patellar tendon with a combination of Krackow and Bunnell sutures.
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http://dx.doi.org/10.1097/BOT.0b013e318191c353DOI Listing
January 2009

The use of surgical drains in orthopedics.

Orthopedics 2008 Jul;31(7):702-5

Department of Orthopedic Surgery, Bone and Joint/Sports Medicine Institute, Naval Medical Center Portsmouth, Virginia 23708, USA.

The use of postsurgical drains have a long history in thoracic and abdominal surgery. In orthopedics these devices have been used to decrease local edema, lessen the potential for hematoma or seroma formation, and to aid in the efflux of infection. However, the role of postoperative surgical drains in clean, elective cases has not been firmly established. In fact, most studies fail to show a statistical difference in outcome between drained and undrained patients. Despite the paucity of clinical evidence demonstrating any benefit supporting their use, drains continue to be placed after elective orthopedic procedures.
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http://dx.doi.org/10.3928/01477447-20110505-06DOI Listing
July 2008