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196 citation(s) found for "Shin, Alexander Y".

Bone Grafting for Scaphoid Nonunions: Is Free Vascularized Bone Grafting Superior for Scaphoid Nonunion?
Aibinder, William R. , Wagner, Eric R. , Wagner, Eric R , Bishop, Allen T. , Shin, Alexander Y. , Aibinder, William R

Mayo Clinic

HAND | October 28, 2017 | Volume: 14 | Issue: 2 | Pages: 217-222

10.1177/1558944717736397 | PMID 29078719 Get It

Background: Nonvascularized bone grafting (NVBG) and vascularized bone grafts (VBGs) have been used to treat scaphoid nonunions. A comparison of a single institution’ s experience using structural iliac crest bone graft (ICBG), 1,2-intercompartmental supraretinacular artery (1,2-ICSRA), and medial femoral condyle (MFC) grafts to treat scaphoid nonunions was undertaken. Methods: Thirty-one patients underwent ICBG, 33 patients underwent 1,2-ICSRA, and 45 patients underwent MFC grafting. Mean time to follow-up was 16 months (range, 2-153). Twenty-three percent used tobacco products. Mean age was 24 years (range, 11-66), with 86% male patients. Outcomes included union rate, time to healing, range of motion, complications, and reoperations. Results: Union rates and mean time to union were 71% and 19 weeks for the ICBG group, 79% and 26 weeks for the 1,2-ICSRA group, and 89% and 16 weeks for the MFC group, respectively. Failure of union was associated with tobacco use but not with age, gender, time from injury to surgery, or type of fixation. There was no significant difference between the groups regarding range of motion or strength. Conclusions: These findings demonstrate the need for careful patient selection. In patients with the most complicated scaphoid nonunions (avascular necrosis, carpal collapse, and previous surgeries), the MFC group had the highest union rate and fastest time to union. Patients with risk factors for failure should be counseled on the outcomes and possible need for salvage fusion surgery.
Vascularized Bone Grafts in Orthopaedic Surgery
Shin, Emily H. , Shin, Alexander Y.

Mayo Clinic

JBJS Reviews | October 3, 2017 | Volume: 5 | Issue: 10 | Pages: e1-e1

10.2106/jbjs.rvw.16.00125 | PMID 28976444 Get It

* Preclinical animal studies have demonstrated that vascularized bone grafts increase blood flow, maintain patent pedicles, provide immediate structural integrity, hypertrophy in response to mechanical stress, and deliver proper environments for healing in challenging situations. * The absolute indications for vascularized bone graft as borne out by high-quality studies have yet to be defined. Currently, the literature suggests varying success rates for difficult reconstructive problems requiring additional biological and structural properties offered only by vascularized bone-grafting. * Orthopaedic reconstructive challenges can be met with a variety of options, including pedicled and free vascularized bone grafts.
Smartphone photography utilized to measure wrist range of motion
Wagner, Eric R. , Mica, Megan Conti , Wagner, Eric R , Shin, Alexander Y.

Mayo Clinic

Journal of Hand Surgery (European Volume) | September 5, 2017 | Volume: 43 | Issue: 2 | Pages: 187-192

10.1177/1753193417729140 | PMID 28872411 Get It

The purpose was to determine if smartphone photography is a reliable tool in measuring wrist movement. Smartphones were used to take digital photos of both wrists in 32 normal participants (64 wrists) at extremes of wrist motion. The smartphone measurements were compared with clinical goniometry measurements. There was a very high correlation between the clinical goniometry and smartphone measurements, as the concordance coefficients were high for radial deviation, ulnar deviation, wrist extension and wrist flexion. The Pearson coefficients also demonstrated the high precision of the smartphone measurements. The Bland–Altman plots demonstrated 29–31 of 32 smartphone measurements were within the 95% confidence interval of the clinical measurements for all positions of the wrists. There was high reliability between the photography taken by the volunteer and researcher, as well as high inter-observer reliability. Smartphone digital photography is a reliable and accurate tool for measuring wrist range of motion. Level of evidence: II
The effect of full dose composite tissue allotransplantation immunosuppression on allograft motor nerve regeneration in a rat sciatic nerve model
Kim, Jong Pil , Hundepool, Caroline A. , Friedrich, Patricia F. , Moran, Steven L. , Bishop, Allen T. , Shin, Alexander Y.

Mayo Clinic

Microsurgery | August 9, 2017 | Volume: 38 | Issue: 1 | Pages: 66-75

10.1002/micr.30211 | PMID 28792625 Get It

BackgroundThe purpose of this study was to identify which triple immunosuppressive protocols, currently used for vascularized composite allotransplantation in the clinic, will have the best effect on motor function recovery following nerve allograft reconstruction.MethodsEighty‐eight Lewis rats underwent a 1‐cm sciatic nerve allograft transplantation and skin graft from 44 Brown‐Norway rats. Group I received 0.9% isotonic saline (control); Group II, 2 mg/kg FK506; Group III, 1 mg/kg FK506 with 15 mg/kg mycophenolate mofetil (MMF); and Group IV, 2 mg/kg FK506 with 30 mg/kg MMF and prednisone. Each group consisted of 11 rats. After 12 weeks, motor function recovery was evaluated with isometric tetanic force, muscle mass, ankle contracture angle, electrophysiology, and nerve histomorphometry. Adequacy of immunosuppression was monitored with the transplanted skin graft. All data are expressed as a percentage of the contralateral side.ResultsIsometric tetanic force showed significantly better functional recovery in all groups treated with immunosuppression compared to control. Within the immunosuppression groups no significant difference was found: 42.1 ± 6.4% (Group I), 56.1 ± 12.4% (Group II), 58.4 ± 10.7% (Group III), and 61.3 ± 11.2% (Group IV). Group IV was superior to all other groups regarding ankle contracture (P < .05) and electrophysiology (P < .001). Skin graft rejection occurred in 41 and 0% (Groups III and IV, respectively).ConclusionsFK506 significantly enhanced motor recovery after allograft reconstruction. This effect was comparable between combination treatment (low‐dose FK506 and MMF) and triple therapy (high‐dose FK506 and MMF plus prednisolone). However, triple therapy was more effective in suppressing skin rejection.
Evaluate muscle tension using intramuscular pressure device in rabbit tibialis anterior model for improved tendon transfer surgery
Evertz, Loribeth Q., Bulstra, Liselotte F. , Shin, Alexander Y. , Kaufman, Kenton R.

Mayo Clinic

Physiological Measurement | March 16, 2017 | Volume: 38 | Issue: 7 | Pages: 1301-1309

10.1088/1361-6579/aa6739 | PMID 28301328 Get It

Abstract Quantitative evaluation of passive tension in a muscle is important in tendon transfer surgeries, however, currently appropriate intraoperative measurement techniques are lacking. Objective : Intramuscular pressure (IMP) is explored as an application to access force. Approach : The tibialis anterior (TA) in New Zealand white rabbits ( n = 9) was used to test the hypothesis of a strong correlation between the IMP, muscle force, and length. This study also helped to develop intraoperative techniques for future human studies evaluating various insertion techniques (parallel versus perpendicular). Main results : The Pearson correlation between IMP and force for all trials was 0.74 ± 0.30. Separating out the parallel insertion from the perpendicular insertion revealed a significantly higher correlation for parallel, 0.91 ± 0.13 versus 0.56 ± 0.32. Significance : These data indicate IMP sensors can be used to assess force in a single muscle and the parallel insertion method should be used. New findings • What is the central question of this study? Successful outcomes of tendon and muscle transfers depend on proper muscle tension. A near linear relationship has been seen between muscle force and intramuscular pressure. This study aims to develop an intraoperative technique for assessing passive muscle tension using intramuscular pressure. • What is the main finding and its importance? The findings from this study reveal a high correlation between pressure and passive tension in a single muscle. The techniques developed in this study will allow the translation to a human model. The work will help to improve surgical outcomes and aim to retain muscle strength in the patient following procedures such as tendon and muscle transfers.
Treatment of Ulnar Collateral Ligament Injuries of the Thumb
Pulos, Nicholas , Shin, Alexander Y.

Mayo Clinic

JBJS Reviews | March 1, 2017 | Volume: 5 | Issue: 2 | Pages: No page available

10.2106/jbjs.rvw.16.00051 | PMID 28248741 Get It

➢ Ulnar collateral ligament injuries are best classified according to chronicity of injury and grade of tear, with partial tears and nondisplaced tears being amenable to nonoperative treatment. ➢ In general, acute injuries may be primarily repaired with suture-anchor fixation, most often to the insertion of the ligament on the proximal phalanx, which allows for early joint range of motion. ➢ Symptomatic chronic injuries may be managed surgically with primary repair, reconstruction, or arthrodesis.
Optimizing decellularization techniques to create a new nerve allograft: an in vitro study using rodent nerve segments
Hundepool, Caroline A. , Nijhuis, Tim H.J., Kotsougiani, Dimitra , Friedrich, Patricia F. , Bishop, Allen T. , Shin, Alexander Y.

Mayo Clinic

Neurosurgical Focus | March 1, 2017 | Volume: 42 | Issue: 3 | Pages: E4

10.3171/2017.1.focus16462 | PMID 28245670 Get It

OBJECTIVE Commercially available processed nerve allografts have been shown to be inferior to autografts in previous animal studies. The authors hypothesized that combining different processing and storage techniques will result in improved nerve ultrastructure preservation, lower immunogenicity, and minimized cellular debris. Different processing protocols were evaluated using chemical detergents, enzymes, and irradiation, with the addition the of enzyme elastase, were used. Additionally, the difference between cold and frozen storage was investigated. The goal of this study was to create an optimized nerve allograft. METHODS Fifty rat nerves were decellularized with modifications of previous protocols and the addition of elastase. Subsequently, the nerve segments were stored at either 4°C or −80°C. Both processed and fresh control nerves were analyzed with confocal microscopy using immunohistochemical staining on the basal lamina (laminin γ-1), Schwann cells (S100 protein), and immunogenicity using major histocompatibility complex–I (MHCI) staining. Morphology of the ultrastructure and amount of cellular debris were analyzed on cross-sections of the nerves stained with toluidine blue and H & E, and by using electron microscopy. RESULTS Nerve ultrastructure was preserved with all decellularization protocols. Storage at −80°C severely altered nerve ultrastructure after any decellularization method. Elastase was found to significantly reduce the immunogenicity and amount of Schwann cells, while maintaining good structural properties. CONCLUSIONS Reduced immunogenicity, diminished cellular debris, and the elimination of Schwann cells was observed when elastase was added to the nerve processing while maintaining ultrastructure. Storage at −80°C after the decellularization process heavily damaged the nerve ultrastructure as compared with cold storage. Further in vivo studies are needed to prove the nerve regenerative capacity of these optimized allografts.
Wrist Instability
Carlsen, Brian T. , Shin, Alexander Y.

Mayo Clinic

Scandinavian Journal of Surgery | January 11, 2017 | Volume: 97 | Issue: 4 | Pages: 324-332

10.1177/145749690809700409 | PMID 19211387 Get It

The topic of wrist or carpal instability has been a source of confusion and miscommunication for decades. The terminology can often be difficult to understand and one surgeon's concept of instability may be completely different from another's. This is by no means a comprehensive review of carpal instability, which has often been the focus of numerous multi-volume textbooks. The purpose of this paper is to detail the basics of carpal instability, the anatomy, pathomechanics, terminology and basic principles of treatment.
The outcome and complications of vascularised fibular grafts
Bayne, Christopher O. , Houdek, Matthew T. , Bishop, Allen T. , Shin, Alexander Y.

Mayo Clinic

The Bone & Joint Journal | January 4, 2017 | Volume: 99-B | Issue: 1 | Pages: 134-138

10.1302/0301-620x.99b1.bjj-2016-0160.r1 | PMID 28053269 Get It

AimsFree vascularised fibular grafting has been used for the treatment of large bony defects for more than 40 years. However, there is little information about the risk factors for failure and whether newer locking techniques of fixation improve the rates of union. The purpose of this study was to compare the rates of union of free fibular grafts fixed with locking and traditional techniques, and to quantify the risk factors for nonunion and failure.Patients and MethodsA retrospective review involved 134 consecutive procedures over a period of 20 years. Of these, 25 were excluded leaving 109 patients in the study. There were 66 men and 43 women, with a mean age of 33 years (5 to 78). Most (62) were performed for oncological indications, and the most common site (52) was the lower limb. Rate of union was estimated using the Kaplan-Meier method and risk factors for nonunion were assessed using Cox regression. All patients were followed up for at least one year.ResultsThe rate of union was 82% at two years and 97% at five years. Union was achieved after the initial procedure in 76 patients (70%) at a mean of ten months (3 to 19), and overall union was achieved in 99 patients (91%). No surgical factor, including the use of locked fixation or supplementary corticocancellous bone grafts increased the rate of union. A history of smoking was significantly associated with a risk of nonunion.DiscussionFree vascularised fibular grafting is a successful form of treatment for large bony defects. These results suggest that the use of modern techniques of fixation does not affect the risk of nonunion when compared with traditional forms of fixation, and smoking increases the risk of nonunion following this procedure. Cite this article: Bone Joint J 2017;99-B:134–8.
What Factors Influence the Outcome of Surgically Treated Soft Tissue Sarcomas of the Hand and Wrist?
Wilke, Benjamin K. , Rose, Peter S. , Walczak, Brian E, Houdek, Matthew T. , Walczak, Brian E. , Kakar, Sanjeev , Shin, Alexander Y. , Wilke, B K

Mayo Clinic

HAND | October 3, 2016 | Volume: 12 | Issue: 5 | Pages: 493-500

10.1177/1558944716672197 | PMID 28832212 Get It

Background: Soft tissue sarcomas (STS) of the hand are exceedingly rare. The aim of this study was to review our institution’s experience with STS of the hand to identify factors affecting outcomes and survivorship. Methods: We retrospectively reviewed the records of 46 hand STS treated with definitive surgery at our institution between 1992 and 2013. Pertinent demographics as well as information regarding the surgical procedure, and disease status at latest follow-up were reviewed. Mean age at diagnosis was 38 years with a mean follow-up of 5 years. Results: The most common tumor subtypes were epithelioid (n = 10) and synovial sarcoma (n = 8). Sixty-one percent were superficial in location. Thirty-three patients had had a nononcologic resection prior to definitive surgical treatment at our institution. Ultimately, negative margins were obtained in all cases. Local recurrence was observed in 5 patients and distant metastases in 14 patients. Tumor sizes ≥2 cm, American Joint Committee on Cancer (AJCC) grade, and depth of the tumor were found to adversely affect the outcome in terms of disease-free and overall survival. Reexcision of an inadvertently excised tumor at an outside institution did not adversely affect the outcome. The 10-year overall and disease-free survival was 72% and 63%. Conclusions: Local recurrence after a wide excision was observed infrequently; however, distant disease was relatively common. Tumors with a size ≥2 cm were associated with a worse disease-free and overall survival, highlighting the aggressive nature of these tumors.