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Biomedical subjects

Alexander Y Shin

Publications and source records attributed to Alexander Y Shin.

At least 37 records · Page 2Linked to original sources
PubMed2005

Vascularized free fibula transfer for oncologic reconstruction of the humerus.

UNLABELLED: Reconstruction of the humerus after oncologic resection is challenging. Vascularized free-fibula transfer allows the potential for rapid autograft incorporation in areas compromised by radiation, chemotherapy, and resection. A retrospective case series of vascularized free-fibula transfers for humeral reconstructions is reported. Fifteen patients were identified; nine had surgery for glenohumeral arthrodesis (three primary fusions, six salvage/revision), four had surgery for intercalary defects (three primary reconstructions, one salvage), one patient had an onlay graft for a pathologic fracture in irradiated bone, and one patient had an osteoarticular graft. Average followup was 68 months. One patient died from disease 41 months after surgery. Oncologic outcome was excellent with no local recurrence and preservation of all limbs. There were an average of 0.8 major complications (requiring reoperation) and 0.5 minor complications per patient. The most frequent complication was fracture, occurring in six of 15 patients. All patients went on to bony union except two patients with glenohumeral arthrodesis with asymptomatic fibrous unions. Mean time to union was 12 months. Vascularized free fibula transfer provides an effective and successful means of limb-preserving reconstruction after oncologic resection of the humerus. Healing time may be prolonged, and refracture and other complications commonly are encountered. LEVEL OF EVIDENCE: Therapeutic study, Level IV-1 (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Bone Neoplasms↗
PubMed2005

Adult traumatic brachial plexus injuries.

Adult traumatic brachial plexus injuries are devastating, and they are occurring with increasing frequency. Patient evaluation consists of a focused assessment of upper extremity sensory and motor function, radiologic studies, and, most important, preoperative and intraoperative electrodiagnostic studies. The critical concepts in surgical treatment are patient selection as well as the timing and prioritizing of restoration of function. Surgical techniques include neurolysis, nerve grafting, neurotization, and free muscle transfer. Results are variable, but increased knowledge of nerve injury and repair, as well as advances in microsurgical techniques, allow not only restoration of elbow flexion and shoulder abduction but also of useful prehension of the hand in some patients.

Adult↗
PubMed2005

Ulnar-sided wrist pain: diagnosis and treatment.

Ulnar-sided wrist pain has often been equated with low back pain because of its insidious onset, vague and chronic nature, intermittent symptoms, and frustration that it induces in patients. Chronic ulnar-sided wrist pain may be accompanied by a history of workers' compensation claims and unrelenting and irresolvable pain, and it may occur in patients with dfficult personalities. Despite these issues, many patients with ulnar-sided wrist pain have pathologic lesions that may be amenable to surgical treatment.

Arthralgia↗
PubMed2004

Gracilis free muscle transfer for restoration of function after complete brachial plexus avulsion.

OBJECT: The authors report the functional outcomes after functioning free muscle transfer (FFMT) for restoration of the upper-extremity movement after brachial plexus injury (BPI). METHODS: The authors conducted a retrospective review of 36 gracilis FFMT procedures performed in 27 patients with BPI between 1990 and 2000. Eighteen patients underwent a single gracilis FFMT procedure for restoration of either elbow flexion (17 cases) or finger flexion (one case). Nine patients underwent a double free muscle transfer for simultaneous restoration of elbow flexion and wrist extension (first muscle) and finger flexion (second muscle), combined with direct triceps neurotization. The results obtained in 29 cases of FFMT in which the follow-up period was 1 year are reported. Neurotization of the donor muscle was performed using the musculocutaneous nerve (one case), spinal accessory nerve (12 cases), or multiple intercostal motor nerves (16 cases). Two second-stage muscle flaps failed secondary to vascular insufficiency. Mean electromyography-measured reinnervation time was 5 months. At a minimum follow-up period of 1 year, five muscles achieved less than or equal to Grade M2, eight Grade M3, four Grade M4, and 12 Grade M5. Transfer for combined elbow flexion and wrist extension compared with elbow flexion alone lowered the overall results for elbow flexion strength. Seventy-nine percent of the FFMTs for elbow flexion alone (single transfer) and 63% of similarly innervated muscles transferred for combined motion achieved at least Grade M4 elbow flexion strength. CONCLUSIONS: Functioning free muscle transfer is a viable reconstructive option for restoration of upper-extremity function in the setting of severe BPI. It is possible to achieve good to excellent outcomes in terms of muscle grades with the simultaneous reconstruction of two functions by one FFMT, making restoration of basic hand function possible. More reliable results are obtained when a single FFMT is performed for a single function.

Adolescent↗
PubMed2004

Predicted effects of metacarpal shortening on interosseous muscle function.

PURPOSE: Metacarpal fractures are common in hand surgery. Metacarpal shortening ranging from 2 mm to as much as 10 mm has been deemed acceptable in the literature. We examined the effect of metacarpal shortening on interosseous muscle architecture and predicted force production capacity based on the standard muscle length-tension curve (commonly known as the Blix curve). METHODS: The dorsal interosseous muscles between the middle and ring finger metacarpals from 9 adult human cadaver hands were exposed and studied. The ring finger metacarpal was translated proximally in 2-mm increments in relation to a stationary middle finger metacarpal. Digital images were obtained and analyzed to define the length and orientation of individual muscle fibers with each incremental change in position. RESULTS: Interosseous muscle fiber length increased and pennation angle decreased uniformly with increasing proximal translation of the ring finger metacarpal. At 10 mm of shortening the fiber length had increased to 20.8 +/- 1.8 mm, or to approximately 125% of optimum fiber length, and the pennation angle had decreased to 6.7 degrees +/- 2.2 degrees or by approximately 50%. CONCLUSIONS: The interosseous muscles have been shown to have a high fiber-to-muscle length ratio. This ratio indicates that these muscles function optimally over a short range of lengths, leaving them vulnerable to derangement in function owing to alteration in the surrounding bony architecture. Based on the standard muscle length--tension relationship we had predicted a steady linear decrease in interosseous power with proximal translation of the metacarpal. The results indicate an initial linear progression with a plateau at approximately 8 mm of shortening. At 2 mm of shortening there is an approximately 8% loss of power generation, at 10 mm of metacarpal shortening we predict the interosseous muscle to be capable of only approximately 55% of its optimum power compared with the resting position.

Biomechanical Phenomena↗
PubMed2004

Functional outcomes in young, active duty, military personnel after submuscular ulnar nerve transposition.

PURPOSE: The purpose of this study was to report on the results of submuscular ulnar nerve transposition (SMUNT) for treatment of cubital tunnel syndrome in a young, active duty, military population. METHODS: Twenty patients (20 extremities) were evaluated retrospectively a minimum of 12 months after surgery. Outcome analyses were performed using the Disability of the Arm, Shoulder, and Hand (DASH) questionnaire and the Bishop-Kleinman rating scales, physical examination, return-to-work analysis, evaluation of complication rate, and overall patient satisfaction. RESULTS: At an average follow-up evaluation of 24 months (range, 12-38 mo), 19 patients had returned to full military active duty work status. The average duration of limited work capacity after surgery was 4.8 months (range, 3-7 mo). The DASH scores improved from an average of 32.5 points before surgery to 6.2 points after surgery. In 19 patients the functional outcome evaluated with the Bishop-Kleinman rating system was excellent. There were no poor outcomes using this rating score. Statistically significant improvements in both key pinch and grip strength were noted. Complications included one permanent and 2 transient neuropraxias of the medial antebrachial cutaneous nerve. Overall 19 of 20 patients were satisfied with the procedure and would have the surgery again if required. CONCLUSIONS: Submuscular ulnar nerve transposition for cubital tunnel syndrome provides a reliable rate of return to full active duty work in military personnel with good patient satisfaction and minimal complications.

Adult↗
PubMed2004

Isolated scaphoid dislocation associated with axial carpal dissociation: an unusual injury report.

We present a report of a patient with an isolated scaphoid dislocation associated with a hyperextension and axial loading injury of the carpus required a careful and extensive clinical and radiographic evaluation leading to surgical intervention to reduce and stabilize the scaphoid and to reduce and hold internally the axial carpal injury. Knowledge of the anatomy and the potential injury patterns of the carpus will aid the hand surgeon with injury recognition and proper treatment.

Adult↗
PubMed2004

Percutaneous fixation of stable scaphoid fractures.

The increased awareness of scaphoid fractures and their complications has prompted early aggressive treatment to prevent the sequelae of nonunions and degenerative changes in the carpus. Despite this, many fractures require prolonged immobilization, often resulting in diminished motion and time lost in sports or employment. In an effort to diminish the time to union and decrease prolonged immobilization, percutaneous fixation techniques have been described and recently popularized by several authors. The indications and contraindications, technique, complications, and rehabilitation of treatment of both dorsally and volarly placed percutaneous screw fixation of stable scaphoid fractures will be the focus of this paper.

Journal Article↗
PubMed2004

The efficacy of ultrasound in the evaluation of dynamic scapholunate ligamentous instability.

BACKGROUND: The accuracy of diagnostic imaging modalities that are currently used to evaluate dynamic scapholunate ligamentous instability is equivocal. Ultrasound is commonly used for a wide variety of diagnostic purposes in orthopaedics. The purpose of the present study was to determine the efficacy of ultrasound in the diagnosis of dynamic scapholunate ligamentous instability. METHODS: Two groups of individuals were prospectively studied. Group A included patients with a clinical diagnosis of unilateral dynamic scapholunate ligamentous instability, and Group B included asymptomatic volunteer control subjects. Dynamic ultrasound examinations of the dorsal portion of the scapholunate ligament in both wrists of all individuals were performed by radiologists. The radiologists were blinded with regard to the group to which each person belonged as well as with regard to the affected wrist in the patients in Group A. Arthroscopic examinations of the affected wrist in all of the patients in Group A were then performed by surgeons who were blinded with regard to the results of the ultrasound examination, and the results of the arthroscopic and ultrasound examinations were compared. The ability of ultrasound to discern asymptomatic from symptomatic individuals was also determined. RESULTS: Over a period of 1.5 years, a total of sixty-four wrists were evaluated in fourteen patients (Group A) and eighteen normal subjects (Group B). All fourteen nonaffected wrists in Group A and all thirty-six wrists in Group B were correctly identified as normal with use of ultrasound. Of the fourteen affected wrists in Group A, thirteen were found to have scapholunate ligament laxity on the basis of arthroscopy (twelve wrists) or arthrotomy (one wrist); six of these thirteen wrists had been correctly identified as abnormal with use of ultrasound (a true-positive result), and seven had false-negative results. There was one true-negative result. The ability of ultrasound to differentiate between normal and abnormal wrists was significant (p < 0.001). For the sixty-four wrists, statistical analysis revealed that ultrasound had a sensitivity of 46.2%, a specificity of 100%, and an accuracy of 89.1%. CONCLUSIONS: We conclude that ultrasound has a high specificity and accuracy but a low sensitivity for the evaluation of dynamic scapholunate ligamentous instability, and we recommend its use as an adjunct to other diagnostic modalities for this purpose.

Adult↗
PubMed2003

Mycobacterium marinum infections of the distal upper extremities: clinical course and imaging findings in two cases with delayed diagnosis.

Mycobacterium marinum infections cause tenosynovitis of the distal upper extremities and develop as a consequence of skin abrasions acquired in contaminated water. We report on two patients whose MR imaging studies showed tenosynovitis of the distal upper extremity secondary to M. marinum. In one patient sequential MR imaging showed development of bony erosions. Appropriate treatment was delayed in both patients because the diagnosis was not considered. We report on and discuss the clinical course and MR imaging findings in two patients with M. marinum infection.

Adult↗
PubMed2003

Extension block pinning for large mallet fractures.

PURPOSE: The purpose of this report is to review the results of displaced mallet fractures treated with an extension block pin and transarticular fixation of the distal interphalangeal joint. METHODS: We retrospectively reviewed 23 patients with 24 fractures to determine the results of treatment, time to union, range of motion, and associated complications. RESULTS: The average patient age was 24 years and the average fracture size was 40% of the joint surface. Ten patients were treated acutely (less than 10 days), 10 subacutely (10-30 days), and 3 chronically (greater than 30 days). Average time to fracture union was 35 days. At 1-year or greater follow-up evaluation the average extension loss was 4 degrees and the average flexion was 77 degrees. There were no major complications and there were 5 minor complications. Using the established outcome criteria for mallet injuries, 92% had excellent or good results. CONCLUSIONS: The results of this study showed that this surgical technique resulted in rapid fracture union with only minor complications and has excellent functional outcome based on established criteria.

Adult↗
PubMed2003

Intraosseous metacarpal involvement of giant cell tumor of the tendon sheath: report of 2 cases.

Intraosseous phalangeal growth of giant cell tumor of the tendon sheath (GCTTS) is an uncommon manifestation of this tumor, but it is well known because of its potentially aggressive local growth. This article details the findings of 2 cases of previously unreported intraosseous metacarpal involvement of GCTTS. Differential diagnosis of a metacarpal lesion with decreased radiodensity on radiographs should include GCTTS.

Adult↗
PubMed2002

Thumb radial angulation correction without phalangeal osteotomy in Apert's syndrome.

A surgical technique to correct thumb metacarpophalangeal (MCP) joint radial angulation in patients with Apert's syndrome that obviates osteotomy of the proximal phalanx is described. The anomalous insertion of the abductor pollicis brevis tendon to the distal phalanx radially is released and reattached to the radial base of the proximal phalanx. A radial MCP joint capsulotomy is performed; excision of a cartilaginous prominence on the ulnar aspect of the metacarpal head is required to assist in joint alignment, which is temporarily maintained with a K-wire. Two children underwent bilateral thumb reconstructions using this technique. At 1.5 and 5.6 years after surgery the thumbs were straight and radiographs revealed no residual lateral angulation at the MCP joint. The parents were satisfied with the results. This technique of correction of Apert's thumb radial angulation is simple and reliable and produces satisfactory clinical results.

Acrocephalosyndactylia↗
PubMed2002

Pleomorphic rhabdomyosarcoma in an adult forearm: a case report.

Pleomorphic rhabdomyosarcoma (RMS) is a rare malignancy, and treatment protocols for this tumor are not established. Although Intergroup Rhabdomyosarcoma Study data have led to improvement in overall and disease-free survival for children with juvenile RMS, the applicability of those findings to adult pleomorphic RMS is uncertain. This report presents the case of a 29-year-old man with pleomorphic RMS of the forearm (a location not previously reported in current literature); reviews the immunohistochemical, ultrastructural, and histologic diagnostic criteria; and discusses treatment.

Adult↗
PubMed2002

Extension-block pinning for treatment of displaced mallet fractures.

Mallet injuries are common in active individuals, particularly those who participate in sports such as basketball and football. Although a majority of patients with displaced mallet fractures are treated conservatively with extension splinting, their treatment is often complicated by residual loss of extension and fracture displacement secondary to unfavorable fracture biomechanics and poor patient compliance. An attractive alternative to nonoperative treatment is the minimally invasive technique of extension-block percutaneous pinning. Extension-block percutaneous pinning allows anatomic restoration of the articular surfaces and avoids the complications associated with closed treatment. The technique is easy to perform and is an effective, safe alternative to the conservative treatment of displaced mallet fractures, particularly those associated with joint subluxation.

Athletic Injuries↗