Publications by authors named "Gen Sasaki"

10 Publications

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Irreducible Chronic Volar Dislocation of the Distal Radioulnar Joint After Surgery for Distal Radius Fracture: A Case Report.

JBJS Case Connect 2021 06 11;11(2). Epub 2021 Jun 11.

Department of Orthopaedic Surgery, Mitsui Memorial Hospital, Chiyoda-ku, Tokyo, Japan.

Case: We report a case of irreducible chronic volar dislocation of the distal radioulnar joint (DRUJ) after surgery for distal radius fracture. The patient underwent volar locking plate fixation for distal radius fracture. Despite the satisfactory alignment of the distal radius, irreducible volar dislocation of the DRUJ was discovered at 5 weeks after the initial surgery. DRUJ reconstruction at 9 weeks after injury using the Adams-Berger procedure resulted in a stable and functional DRUJ and wrist.

Conclusion: To prevent postoperative DRUJ instability or dislocation, the DRUJ should be evaluated for stability immediately after fracture fixation.
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http://dx.doi.org/10.2106/JBJS.CC.20.00838DOI Listing
June 2021

Double plating for long-standing nonunion of the humeral shaft complicated with metaphyseal bone defect and deformity: A case report.

Trauma Case Rep 2021 Apr 1;32:100448. Epub 2021 Mar 1.

Department of Orthopaedics, Teikyo University School of Medicine, Tokyo, Japan.

Several treatment methods for nonunion of humeral fracture have been reported with satisfactory results. However, treatment of a long-standing nonunion of the humerus is more challenging, as it may be complicated by broken implants and bone defects. Little is known about treatment strategies for long-standing humeral nonunion with bone defects, especially in the metaphyseal area. We report a case of long-standing humeral shaft nonunion complicated by a bone defect and deformity, treated with double locking plates and an iliac bone autograft.
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http://dx.doi.org/10.1016/j.tcr.2021.100448DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7941154PMC
April 2021

Clinical and radiological assessment of the induced membrane technique using beta-tricalcium phosphate in reconstructive surgery for lower extremity long bone defects.

Bone Joint J 2021 Mar;103-B(3):456-461

Department of Orthopaedic Surgery, Teikyo University School of Medicine, Tokyo, Japan.

Aims: To clarify the effectiveness of the induced membrane technique (IMT) using beta-tricalcium phosphate (β-TCP) for reconstruction of segmental bone defects by evaluating clinical and radiological outcomes, and the effect of defect size and operated site on surgical outcomes.

Methods: A review of the medical records was conducted of consecutive 35 lower limbs (30 males and five females; median age 46 years (interquartile range (IQR) 40 to 61)) treated with IMT using β-TCP between 2014 and 2018. Lower Extremity Functional Score (LEFS) was examined preoperatively and at final follow-up to clarify patient-centered outcomes. Bone healing was assessed radiologically, and time from the second stage to bone healing was also evaluated. Patients were divided into ≥ 50 mm and < 50 mm defect groups and into femoral reconstruction, tibial reconstruction, and ankle arthrodesis groups.

Results: There were ten and 25 defects in the femur and tibia, respectively. Median LEFS improved significantly from 8 (IQR 1.5 to 19.3) preoperatively to 63.5 (IQR 57 to 73.3) at final follow-up (p < 0.001). Bone healing was achieved in all limbs, and median time from the second stage to bone healing was six months (IQR 5 to 10). Median time to bone healing, preoperative LEFS, or postoperative LEFS did not differ significantly between the defect size groups or among the treatment groups.

Conclusion: IMT using β-TCP provided satisfactory clinical and radiological outcomes for segmental bone defects in the lower limbs; surgical outcomes were not influenced by bone defect size or operated part. Cite this article:  2021;103-B(3):456-461.
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http://dx.doi.org/10.1302/0301-620X.103B3.BJJ-2020-1542.R1DOI Listing
March 2021

Extensor Tendon Dislocation at the Metacarpophalangeal Joint of Both Ring Fingers Caused by a Specific Hand Posture in a Shiatsu Therapist.

Case Rep Orthop 2020 22;2020:6842986. Epub 2020 Sep 22.

Department of Orthopaedic Surgery, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8606, Japan.

A 43-year-old female shiatsu therapist complained of sudden snapping of the metacarpophalangeal joints (MCPjs) of both ring fingers during a specific hand posture. The extensor tendon of the ring finger was dislocated ulnarly when the MCPj of the ring finger was flexed and deviated ulnarly and the MCPj of the middle finger was extended. Surgical exploration revealed an attenuated radial sagittal band. We plicated the juncturae tendinum of the extensor digitorum communis between the middle and ring fingers and released the ulnar sagittal band partially to centralise the extensor tendon excursion. Twenty-six months postoperatively, the patient regained full active and passive range of motion of all fingers without extensor tendon dislocation or snapping in either hand during work.
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http://dx.doi.org/10.1155/2020/6842986DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7530478PMC
September 2020

Corrective Intra-Articular Osteotomy Using a 3D-Printed Model and Induced Membrane Technique for AO/OTA C3 Distal Femur Fracture with Articular Malunion and Metaphyseal Nonunion.

Case Rep Orthop 2020 28;2020:1250231. Epub 2020 Jan 28.

Department of Orthopaedics, Teikyo University School of Medicine, Japan.

Comminuted distal femur fracture is a challenging injury, and care must be taken to reduce the articular fragment and acquire the sufficient stability for the metaphyseal comminution. We report the case of a AO/OTA C3-type distal femur fracture with articular malunion and metaphyseal nonunion. Articular malunion was treated with corrective osteotomy using a 3D-printed model for planning, and metaphyseal nonunion was treated with an induced membrane technique. . Two major complications in the comminuted periarticular fracture can be addressed by an osteotomy and induced membrane technique. A 3D-printed model is a useful tool to evaluate the morphology of the malunited articular surface.
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http://dx.doi.org/10.1155/2020/1250231DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7007957PMC
January 2020

Conservative Treatment of an Intra-Articular Shear Fracture of the Ulnar Head.

J Wrist Surg 2019 Oct 10;8(5):426-429. Epub 2019 Jan 10.

Trauma and Reconstruction Center, Teikyo University Hospital, Tokyo, Japan.

 Isolated intra-articular fracture of the ulnar head is rare.  A 59-year-old woman experienced an ulnar head fracture involving the distal radioulnar joint after a fall at ground level. The intra-articular fragment of the ulnar head was rotated into anatomical alignment with an above-elbow cast in 90° of supination for 4 weeks. A below-elbow night splint was retained for 2 additional weeks. Twelve months post-injury, full active motion and bone union were achieved.  Only three studies have reported treatment of isolated intra-articular ulnar head fractures, and in all cases open reduction and internal fixation were performed.  Our report demonstrated good results for the conservative treatment of an intra-articular ulnar head shear fracture, with early recovery of forearm rotation and wrist function.
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http://dx.doi.org/10.1055/s-0038-1677533DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6773575PMC
October 2019

Nonunion of the sternum treated with cervical locking plate: A case report.

J Orthop Sci 2020 Nov 2;25(6):1119-1122. Epub 2018 Mar 2.

Department of Orthopaedics, Teikyo University Hospital, Japan.

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http://dx.doi.org/10.1016/j.jos.2018.02.005DOI Listing
November 2020

Chipping and lengthening over nailing technique for femoral shaft nonunion with shortening.

Int Orthop 2017 09 21;41(9):1859-1864. Epub 2017 Jun 21.

Department of Orthopaedic Surgery, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi, Tokyo, 173-8605, Japan.

Purpose: Chipping and lengthening over nailing (CLON) technique was developed to treat femoral shaft nonunion with shortening more than 10 mm. The purpose of the current retrospective case series was to clarify the effectiveness of the CLON technique on the femoral shaft nonunion following intramedullary nailing.

Methods: Clinical and radiological outcomes in the patients receiving operative treatment for femoral shaft nonunion between August 2012 and December 2016 were retrospectively reviewed using the Refractory Fracture Data Registry at the authors' institution. The CLON technique was indicated for patients with the femoral shaft nonunion with shortening more than 10 mm.

Results: Five patients with median follow-up of 32 months (range, 14 to 50 months) were included in this study. All patients achieved bone union at the median of 8 months after the CLON technique. The median limb length discrepancy was 2.0 mm at the most recent follow-up.

Conclusions: The present study demonstrated that the CLON technique for femoral shaft nonunion may be the first choice as operative treatment for femoral shaft nonunion with shortening more than 10 mm.
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http://dx.doi.org/10.1007/s00264-017-3535-xDOI Listing
September 2017

Induced membrane technique using beta-tricalcium phosphate for reconstruction of femoral and tibial segmental bone loss due to infection: technical tips and preliminary clinical results.

Int Orthop 2018 01 24;42(1):17-24. Epub 2017 May 24.

Department of Orthopaedic Surgery, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi, Tokyo, 173-8605, Japan.

Purpose: This study aimed to provide preliminary evidence regarding effectiveness of grafting beta-tricalcium phosphate (β-TCP) combined with a cancellous autograft for treating nonunion of long bones in the lower extremity due to infection by evaluating clinical and radiological outcomes.

Methods: We retrospectively reviewed the clinical and radiological results in seven patients (six men, one woman; median age 39 years) treated by the induced membrane technique for nonunion of the femur or tibia due to infection. In the second stage of the procedure, the bony defect was filled with a combination of autologous cancellous bone and β-TCP, which were mixed in approximately the same proportions. The time interval between the second stage of the procedure and bone healing was investigated. Radiographic characteristics including maximum bone gap and radiographic apparent bone gap were evaluated.

Results: The median follow-up period was 14 months. Bone healing was achieved in a median of six months after the second procedure. The median maximum bone gap and radiographic apparent bone gap were 55 mm and 34 mm, respectively.

Discussion: Use of β-TCP, which has osteoconductive ability, with an autograft provided good clinical and radiological outcomes. The findings of this preliminary study suggest the potential of β-TCP as a useful bone substitute for autografts in the induced membrane technique.

Conclusions: Our findings suggest that β-TCP may be an effective extender when using the induced membrane technique.
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http://dx.doi.org/10.1007/s00264-017-3503-5DOI Listing
January 2018

Development of advanced fermentor control applications for use in an industrial automation environment.

J Lab Autom 2013 Apr 27;18(2):137-42. Epub 2012 Dec 27.

Pharma Technical Development, Genentech, South San Francisco, CA 94080, USA.

We present a software platform developed by Genentech and MathWorks Consulting Group that allows arbitrary MATLAB (MATLAB is a registered trademark of The MathWorks, Inc.) functions to perform supervisory control of process equipment (in this case, fermentors) via the OLE for process control (OPC) communication protocol, under the direction of an industrial automation layer. The software features automated synchronization and deployment of server control code and has been proven to be tolerant of OPC communication interruptions. Since deployment in the spring of 2010, this software has successfully performed supervisory control of more than 700 microbial fermentations in the Genentech pilot plant and has enabled significant reductions in the time required to develop and implement novel control strategies (months reduced to days). The software is available for download at the MathWorks File Exchange Web site at http://www.mathworks.com/matlabcentral/fileexchange/36866.
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http://dx.doi.org/10.1177/2211068212471671DOI Listing
April 2013
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