Biomedical subjects

Alexander Y Shin

Publications and source records attributed to Alexander Y Shin.

At least 19 recordsLinked to original sources

PubMed2007

The clinical implications of scaphotrapezium-trapezoidal arthritis with associated carpal instability.

PURPOSE: Common causes of dorsal intercalated segment instability (DISI) include scapholunate dissociations and scaphoid fracture nonunions. Although less common than these, scaphotrapezium-trapezoidal (STT) osteoarthritis (OA) may also be associated with the development of a DISI deformity. The clinical implications of this form of carpal instability in cases of STT arthritis are still unknown. To study the radiographic progression and incidence of this entity, we reviewed our patients and report on 24 wrists with DISI in the presence of STT arthritis. METHODS: A retrospective chart and radiographic review was performed on all patients seen between 1994 and 2004, with the diagnosis of STT arthritis to identify a subgroup of patients with DISI deformity on the presenting radiographs. Patients' clinical and surgical courses were noted. Postoperative radiographic changes were recorded, as were clinical outcomes. RESULTS: Sixteen patients with 24 wrists having STT arthritis and DISI deformity on presenting radiographs were identified. The median STT arthritis grade was 3.0 based on a modified Eaton and Glickel grading system. The median radiolunate angle was -21 degrees of dorsal tilt. All patients had normal scapholunate angles. Abnormal scaphoid extension was seen in 19 of 24 wrists as measured by the radioscaphoid angle. Concomitant carpometacarpal arthritis was seen in 67% (n = 16) of the wrists, and midcarpal arthritis was identified in 50% (n = 8) of patients. Fifteen wrists required surgery for the symptoms and were followed up for a mean of 29 months after surgery. In the surgical group the radiolunate angles increased by mean of 6 degrees after surgery. Four of the 15 wrists required revisional surgery for persistent pain. CONCLUSIONS: Patients with STT arthritis may present with carpal instability that is not related to radiographic scapholunate instability. This instability is characterized by a normal scapholunate angle with an extension stance of the scaphoid and lunate. Midcarpal arthritis may be present. Surgical intervention for patients with STT arthritis and DISI deformity may lead to radiographic progression of midcarpal instability.

Adult↗

PubMed2007

Vascularized bone grafting for the treatment of carpal pathology.

Vascularized bone graft procedures have been applied to several maladies of the carpus including proximal pole fractures of the scaphoid, Preiser's disease, and Kienböck's disease. Vascularized bone grafts are capable of primary bony healing without creeping substitution and can thus accelerate fracture healing, replace deficient bone, and revascularize ischemic bone. Long-term data are now available to evaluate the benefits and deficiencies of vascularized grafts in the treatment of many carpal maladies. This article reviews the pertinent literature and provides some treatment algorithms for the use of vascularized bone grafting in cases of carpal pathology.

Bone Diseases↗

PubMed2007

The role of vascularized bone grafts in spine surgery.

The use of vascularized bone grafts in complex spine reconstruction is particularly attractive in situations that involve large segmental bone defects, failed previous attempts at arthrodesis, poor soft tissue beds secondary to infection or radiation exposure necrosis or failed arthrodesis in neuromuscular disease processes. This article details the indications and rationale for vascularized bone grafting as well as the results of vascularized bone grafting of the spine.

Animals↗

PubMed2006

Scaphoid fracture in children.

Scaphoid fractures in children are uncommon. A high index of suspicion is required in children when clinical signs and symptoms indicate a scaphoid fracture in a child. Radiographic evaluation with multiple views should be performed to assess for fracture. If necessary, advanced imaging studies such as MRI should be performed. Most scaphoid fractures can be treated with cast immobilization, which results in healing in the vas majority of cases. Scaphoid nonunion is usually the result of delayed presentation or missed diagnosis. Fortunately union can be achieved reliably with cast immobilization or surgical fixation.

Casts, Surgical↗

PubMed2006

Surgical approaches to the carpus.

The increasing numbers of wrist disorders amenable to surgical treatment have resulted in a myriad of described exposures of the wrist. The purpose of this article is to provide an updated review of the commonly used exposures to the carpus and the distal radioulnar joint in a hand surgery practice.

Carpal Bones↗

PubMed2006

The outcomes and complications of 1,2-intercompartmental supraretinacular artery pedicled vascularized bone grafting of scaphoid nonunions.

PURPOSE: Over the past decade vascularized bone grafts that use a 1,2-intercompartmental supraretinacular artery (1,2-ICSRA) pedicle have gained popularity in the treatment of scaphoid nonunions. The purpose of this study was to evaluate critically the outcome, complications, and failures of 1,2-ICSRA-based vascularized bone grafting at our institution to understand better the appropriate indications, methods, and possible contraindications. METHODS: From January 1994 through July 2003, 50 scaphoid nonunions in 49 patients were treated with 1,2-ICSRA-based vascularized bone grafts. A retrospective review of the clinical and radiographic information was performed. Two patients were lost to follow-up study. Nine female and 38 male patients averaging 24 years of age were followed-up for an average of 7.8 months. RESULTS: Thirty-four scaphoid nonunions went on to union at an average of 15.6 weeks after surgery. Complications occurred in 8 patients and consisted of graft extrusion, superficial infection, deep infection, and failure of fixation. Univariate risk factors for failure included older age, proximal pole avascular necrosis, preoperative humpback deformity, nonscrew fixation, tobacco use, and female gender. CONCLUSIONS: Although previous researchers have concluded that vascularized bone grafts based on the 1,2-ICSRA are efficacious in the treatment of scaphoid nonunions, we determined that a successful outcome is not universal and depends on careful patient and fracture selection and appropriate surgical techniques. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic, Level IV.

Adolescent↗

PubMed2006

Upper-extremity mucormycosis infections in immunocompetent patients.

PURPOSE: Mucormycosis can produce an aggressive and sometimes fatal soft tissue infection seen most commonly in immunocompromised individuals. Eradication consists of surgical resection and antifungal chemotherapy. Knowledge regarding infectious mucormycosis in the upper extremity has been limited to case reports involving mainly immunocompromised individuals. The purpose of this study was to identify risk factors for the development of mucormycosis infections within the upper extremity in immunocompetent individuals and to evaluate the effectiveness of the present therapies. METHODS: A 12-year retrospective review of all fungal infections involving the upper extremity was conducted in our institution. Seven immunocompetent patients with infectious cutaneous mucormycosis of the upper extremity were identified from 223 primary upper-extremity fungal infections. RESULTS: In the 7 patients 3 infections resulted from heavy soil contamination after motor vehicle collisions and 4 resulted from conveyor belt injuries in agricultural facilities. All patients had considerable upper-extremity soft tissue loss and 6 of the 7 patients had upper-extremity fractures or dislocations. Patients had an average of 10 surgical debridements. Four infections resulted in amputations: 1 partial hand amputation, 1 below the elbow, 1 above the elbow, and 1 at the glenohumeral joint. CONCLUSIONS: Mucormycosis can produce limb-threatening infections in an immunocompetent host. Hand surgeons must have suspicion of such infections in patients with grossly contaminated open wounds.

Adult↗

PubMed2006

2004-2005 Sterling Bunnell Traveling Fellowship report.

The Bunnell Traveling Fellowship was established in 1982 with the purpose of sponsoring a young hand surgeon in the development of national and international relationships that contribute to his/her pursuit of higher learning and that foster the principles of scholarship of the American Society for Surgery of the Hand. I was fortunate to be selected as the 24th Sterling Bunnell Fellow, and I had the opportunity to follow in the footsteps of the 23 former fellows. In Bunnell's Surgery of the Hand, Fourth Edition (Boyes JH, ed. Philadelphia, Lippincott; 1964:561-567), a man with a brachial plexus injury was described. The recommended treatment was shoulder arthrodesis and transhumeral amputation, followed by fitting of an above-elbow prosthesis. Sterling Bunnell has been quoted as saying, "To someone who has nothing, a little is a lot." Nowhere in the field of hand surgery is this more true than in patients with brachial plexus injuries. The theme and purpose of my traveling fellowship was to evaluate the status and advances of adult brachial plexus surgery throughout the world, to determine the utility of the contralateral C7 nerve transfer, to evaluate the optimal reconstruction of grasp, and finally to determine the philosophies of experts around the world regarding the treatment of these patients.

Fellowships and Scholarships↗

PubMed2006

Dorsal distal radius vascularized pedicled bone grafts for scaphoid nonunions.

Fractures of the scaphoid, particularly its proximal pole, are at risk of progressing to nonunion because of the tenuous, retrograde blood supply. The overall incidence of scaphoid fractures developing nonunion ranges from 10% to 15%, whereas proximal pole fractures of the scaphoid can have up to a 30% incidence of nonunion. Avascular necrosis of these proximal pole fractures can occur in 14% to 39% of cases. Dorsal distal radius vascularized pedicled bone grafting is an alternative to conventional measures for the treatment of displaced proximal pole fractures, established nonunions, and avascular necrosis of the proximal fragment. This graft is based on the 1,2-intercompartmental supraretinacular artery, which has reliable anatomy and predictable course between the first and second extensor compartments. The graft can be harvested and inset into the prepared fracture site using a single-incision approach. The indications, contraindications, technique, and results of treatment are reviewed and detailed.

Bone Transplantation↗

PubMed2006

Treatment of acute scaphoid fractures in the athlete.

Scaphoid fractures in athletes can be very disabling and may limit successful and early return to play. Typically, the mechanism of injury is a fall onto an outstretched hand or a direct blow; the patient will present with swelling, limited motion, and snuffbox tenderness. Multiple-view plain images will very often reveal the diagnosis. In addition, diagnostic modalities such as CT scanning and MRI are helpful in better defining the architecture of the fracture and vascularity of the scaphoid, and diagnosing occult fractures. Early and accurate diagnosis is critical to help ensure appropriate treatment and optimal outcome. Traditional treatment of stable nondisplaced fractures remains cast immobilization. However, if early return to play is desired operative fixation may be warranted. For nondisplaced fractures operative techniques include open reduction and internal fixation (ORIF), and percutaneous fixation through a dorsal or volar approach. Arthroscopy can be used as an adjunct to the percutaneous technique. For displaced fractures, the preferred technique remains ORIF through either a volar or dorsal approach. Considerations in treatment type are based on the stability and location of the fracture as well as patient issues such as compliance and the need for return to play. With appropriate diagnosis and individualization of treatment, scaphoid fractures can be successfully managed in most athletes with few or no long-term sequelae.

Acute Disease↗

PubMed2006

Results of vascularized rib grafts in complex spinal reconstruction.

BACKGROUND: The application of vascularized rib grafts in spine surgery has been limited to the treatment of kyphosis with anterior placement of the rib graft to facilitate anterior spine arthrodesis. The outcomes following use of vascularized rib grafts in complex spinal reconstruction have not been adequately evaluated. The purpose of this study was to determine the results, including the time to osseous union and complications, following anterior or posterior placement of pedicled vascularized rib grafts for complex spinal reconstruction. METHODS: The medical records and images of all patients in whom a vascularized rib graft had been used for a multisegmental spine reconstruction at a single institution between 1994 and 2004 were retrospectively reviewed. Eighteen patients (mean age, 45.3 years) who had been followed for an average of 31.8 months were identified. Details regarding indications, the levels that were spanned, the graft length, the time to union, and complications were evaluated. RESULTS: The preoperative diagnoses included metastatic or primary tumor (thirteen patients) and progressive kyphosis secondary to chronic osteomyelitis (two), injury (one), congenital anomalies (one), or implant failure (one). On the average, 4.4 levels were fused and 1.9 vertebral bodies were excised. All eighteen arthrodeses included various forms of allograft and/or autograft material, and instrumentation was used, in addition to the vascularized rib graft, in twelve patients. The mean rib length was 16.1 cm, and a rib between the fifth and eleventh ribs, inclusive, was used, depending on the location of the spinal reconstruction. The average time to union was 6.8 months, and all rib grafts united. There were no complications specific to the rib-harvesting procedure. CONCLUSIONS: The use of a vascularized rib graft in complex spinal reconstruction adds little time to the overall procedure, is associated with low morbidity, and appears to offer substantial benefits to the patient.

Adolescent↗

PubMed2006

The hypoplastic thumb.

Thumb hypoplasia is part of a spectrum of radial longitudinal deficiencies involving the upper limb. Systemic involvement of other organ systems is not uncommon, thus requiring a team approach to management. Because of the variety of anatomic abnormalities associated with thumb hypoplasia, clinical and intraoperative evaluation of the thumb must be precise. Effective management of thumb hypoplasia requires an understanding of the embryology, epidemiology, classification, presentation, and management options. Management, which is primarily determined by the grade of thumb hypoplasia, may include nonsurgical techniques, reconstruction, pollicization, and, recently, microsurgical procedures.

Hand Deformities, Congenital↗

PubMed2006

The underestimation of a glass injury to the hand.

This study sought to ascertain the differences between what is found on an orthopedic preoperative examination of a glass injury to the hand and the actual intraoperative deficiencies noted in the operating room. The cases of 34 patients who presented to our institution for a shattered glass laceration to the hand, forearm, or wrist between 1998 and 2001 were reviewed. The preoperative examination significantly underestimated the amount of damage to tendons, arteries and nerves. The most frequent injury pattern was the flexor digitorum superficialis (34/103 = 33%), the radial artery (7/18 = 39%), and the superficial branch of the radial nerve (7/32 = 22%). A glass injury to the hand can be a deceivingly debilitating and significant injury. The preoperative examination, even when specifically evaluating for deficiencies, significantly underestimates the extent of damage. If glass is implicated as a causative agent, careful orthopedic evaluation and surgical management should be considered even in light of a normal preoperative examination.

Adolescent↗

PubMed2005

Clinical significance of suprascapular nerve mobilization.

The anatomy of the suprascapular nerve is important to surgeons when focal nerve lesions necessitate surgical repair. Recent experience with a patient who had a complete suprascapular nerve lesion in the retroclavicular region (combined with axillary and musculocutaneous nerve lesions) is presented to illustrate that successful direct nerve repair is possible despite resection of a neuroma. Specifically, we found that neurolysis and mobilization of the suprascapular nerve and release of the superior transverse scapular ligament provided the necessary nerve length to achieve direct nerve repair after the neuroma was removed. A combined supraclavicular and infraclavicular approach to the suprascapular nerve provided excellent visualization, especially in the retroclavicular region. Postoperatively, the patient recovered complete shoulder abduction and external rotation with the direct repair, an outcome uncommonly achieved with interpositional grafting. Based on our operative experience, we set out to quantify the length that the suprascapular nerve could be mobilized with neurolysis. Mobilization of the nerve and release of the superior transverse scapular ligament generated an average of 1.6 cm and 0.7 cm of extra nerve length respectively, totaling 2.3 cm of additional usable nerve length overall. The ability to expose the suprascapular nerve in the retroclavicular/infraclavicular region and to mobilize the suprascapular nerve for possible direct repair has not been previously emphasized and is clinically important. This surgical approach and technique permits direct nerve repair after resection of a focal neuroma in the retroclavicular or infraclavicular region, thus avoiding interpositional grafting, and improving outcomes.

Adult↗

PubMed2005

Adult brachial plexus injuries: mechanism, patterns of injury, and physical diagnosis.

Most brachial plexus injuries involve the entire plexus. An injury to major cords or branches often contains a mixed injury pattern, with portions of the nerve being avulsed, ruptured, or stretched. An advancing Tinel's sign implies the possibility of neurologic recovery; however, the surgeon should combine this physical finding with that of electrodiagnostic studies to assess the extent of nerve injury to allow for expedient surgical intervention when necessary.

Brachial Plexus↗

PubMed2005

Clinically relevant surgical anatomy and exposures of the brachial plexus.

A clear understanding of the anatomy of the brachial plexus and its relationship to vascular,skeletal and muscular anatomy is essential for any surgery of this area. Adequate exposure and delineation of the pathology will allow for accurate treatment of the brachial plexus lesion(s).

Brachial Plexus↗

PubMed2005

The use of the 4 + 5 extensor compartmental vascularized bone graft for the treatment of Kienböck's disease.

PURPOSE: The use of vascularized bone grafts for the treatment of Kienböck's disease may prevent ongoing lunate collapse and provide relief of wrist symptomatology. This study examines our experience with the use of the 4 + 5 extensor compartmental artery (ECA) bone graft for the treatment of Kienböck's disease. METHODS: A retrospective review was performed of all patients having pedicled vascularized bone grafts for Kienböck's disease between 1991 and 2002. Only those patients who had reconstruction with a 4 + 5 ECA graft were included in the study. Presurgical and postsurgical measurements included range of motion, grip strength, and pain evaluation. Measurements of the radiolunate angle, radioscaphoid angle, Stahl's index, and carpal height ratio were taken from presurgical and final follow-up radiographs. Postsurgical magnetic resonance imaging scans were also examined to verify revascularization of the lunate. Statistical analysis was performed using Student's t test. A chi-square test was used to evaluate the effects of lunate revascularization on radiographic progression of disease. Twenty-six 4 + 5 ECA vascularized bone grafts were performed as treatment for Kienböck's disease. The average patient age was 32 years. At the time of surgery 12 patients were graded as stage II, 10 as IIIA, and 4 as IIIB. Mean follow-up time was 31 months. RESULTS: At a mean follow-up of 3 months, motion improved from 68% to 71% of the unaffected side, grip strength improved from 50% to 89% of the unaffected side, and 92% of patients had significant improvement in their pain. Satisfactory results were seen in 85% of patients based on the Lichtman outcome score. Seventy-seven percent of patients showed no further collapse on postsurgical radiographs. Sixty-five percent of patients had follow-up magnetic resonance imaging scans at a mean of 20 months after surgery. Seventy-one percent of patients showed evidence of revascularization with improvement in the T2 and/or T1 signal. CONCLUSIONS: The 4 + 5 ECA bone graft provides a reliable alternative for the treatment of Kienböck's disease and may aid in lunate revascularization.

Adolescent↗

PubMed2005

Acute coronal plane scaphoid fracture and scapholunate dissociation from an axial load: a case report.

Coronal fractures of the scaphoid are rare and can be difficult to diagnose. Axial load injuries that result in a complete coronal fracture of the scaphoid associated with an acute scapholunate dissociation are exceedingly rare. In our patient the radiographic finding of wide scapholunate dissociation was obvious; however, the coronal scaphoid fracture was not recognized initially nor suspected. During surgery the coronal scaphoid fracture was identified, reduced anatomically, and fixed with a compression screw. The scapholunate ligament also was repaired. A good result was obtained with return to sports with extension of 60 degrees and flexion of 70 degrees , grip strength equal to that of the uninjured wrist, and no radiographic problems (arthrosis, avascular necrosis, nonunion).

Adolescent↗