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Biomedical subjects

R M Szabo

Publications and source records attributed to R M Szabo.

At least 19 recordsLinked to original sources
PubMed1999

Dorsal intercarpal ligament capsulodesis for scapholunate dissociation: biomechanical analysis in a cadaver model.

The purpose of this study was to evaluate in cadavers a new method for treating scapholunate dissociations, dorsal intercarpal ligament capsulodesis (DILC), and to compare its performance with that of a previously described soft tissue reconstruction, Blatt capsulodesis (BC). A cadaver model was used to simulate normal and abnormal wrist motions. The positions of the scaphoid and lunate and their changes with wrist motion and ligament condition were recorded using biplanar radiographs taken posteroanteriorly and laterally. The scapholunate gap was measured on the posteroanterior radiographs and the scapholunate angle was measured on the lateral view radiographs. Following scapholunate interosseous ligament sectioning, a diastasis developed between the scaphoid and lunate that was maximum in the clenched fist position 2.1 +/- 0.33 mm (mean +/- SEM) with the ligament intact versus 8.0 +/- 1.74 mm after the ligament was sectioned. Dorsal intercarpal ligament capsulodesis reduced gap formation more than BC, including when the specimens were in the clenched fist position: increased gap versus intact specimens equals 1.0 mm for DILC versus 3.7 mm for BC. The differences in diastasis were statistically significant between BC and DILC when the wrist was in extension, radial deviation, and clenched fist positions. After the scapholunate interosseous ligament was divided, the scaphoid flexed relative to the lunate. Both capsulodeses improved scapholunate alignment and there was a trend for DILC to correct the scapholunate angle more than BC. The results demonstrate that DILC is an attractive alternative to BC ex vivo. Because DILC does not tether the scaphoid to the distal radius, as BC does, improved wrist motion, especially flexion, might be possible in vivo. The use of DILC in the treatment of scapholunate dissociation warrants further investigation and clinical trials.

Adult↗
PubMed1999

Forearm interosseous ligament isometry.

Biomechanical testing was performed to determine isometric interosseous ligament graft placement as a preliminary step for reconstruction after an axial forearm disruption. Twenty-five combinations of potential ligament graft placement were studied on 7 fresh-frozen cadavers. Suture was used to simulate these potential ligament reconstructions, and suture excursion was used as an index of isometry. Ligament orientation was defined by the angle formed between the ulna and the suture (surrogate graft). Ligament position was defined by its insertion on the ulna as a percentage of ulna length. Suture-ulna angles from 9 degrees to 38 degrees produced significantly less suture excursion than angles of > or = 39 degrees. Minimal suture excursion was noted at angles of < or = 20 degrees, which we feel represents the optimal range for reconstruction. The optimal location on the ulna for isometric interosseous ligament reconstruction was at 25% to 30% of total ulna length, as measured proximally from the distal ulna articular surface. The radius isometric location is optimally located by a vector starting from the ulna isometric point and directed toward the proximal radius at an angle of < or = 20 degrees relative to the long axis of the ulna. Interosseous ligament reconstruction may prove beneficial in the long-term outcome of reconstruction after axial forearm disruption.

Aged↗
PubMed1998

Latissimus dorsi pedicled graft. An unusual cause of shoulder pain.

An unusual complication after the use of a pedicled latissimus dorsi flap is reported. The flap was used to reconstruct a facial defect after excision of a high grade mucoepidermoid carcinoma of a parotid gland. The tendinous insertion of the latissimus dorsi on the humerus was left intact and the flap pivoted around this point. Subsequent use of his arm caused the patient disabling shoulder pain from traction on the tendon. Symptoms resolved after the tendon was divided.

Carcinoma, Mucoepidermoid↗
PubMed1998

Carpal tunnel syndrome as a repetitive motion disorder.

The incidence of repetitive motion disorders is increasing and in 1990 comprised 48% of all reported workplace illnesses (up from 18% in 1980). Carpal tunnel syndrome is the most prevalent disease classified as a repetitive motion disorder, thus making its prevention and management an occupational health and safety priority. The clinical picture of carpal tunnel syndrome, pain and paresthesias on the palmar radial aspect of the hand, often worse at night, and/or exacerbated by repetitive, forceful use of the hand, is recognized readily. Carpal tunnel syndrome is a condition of middle aged people and most middle aged people work. It follows that more often than not carpal tunnel syndrome occurs in a work-place setting, and the extent to which the work contributes to the condition is of great interest regarding prevention and treatment. Some studies find little evidence supporting the concept of carpal tunnel syndrome as caused by work, whereas others propose that more than half of cases of carpal tunnel syndrome in workers may be attributed to workplace factors. It is explored whether the incidence, prevalence, and significance of carpal tunnel syndrome as a repetitive motion disorder is known.

Carpal Tunnel Syndrome↗
PubMed1998

Acute carpal tunnel syndrome.

Although the carpal tunnel is open at both ends, it has the physiologic properties of a closed compartment bounded by synovium proximally and distally. When the intracarpal canal interstitial pressure rises above a critical threshold pressure, capillary blood flow is reduced below the level required for median nerve viability. Acute carpal tunnel syndrome is recognized frequently as occurring secondary to wrist trauma and infrequently due to a variety of infectious, rheumatologic, and hematologic disorders. This condition warrants prompt recognition and the treatment is early carpal tunnel release.

Acute Disease↗
PubMed1997

Displacement and strain of the median nerve at the wrist.

Median nerve displacement and strain in the carpal tunnel region were measured as functions of wrist position and carpal tunnel pressure in 5 cadaver forearms during simulated active finger flexion. The positions of spherical stainless-steel markers embedded within the median nerve and flexor digitorum superficialis of the long finger were measured in 3 dimensions by a radiographic direct linear transformation technique. Each limb was tested in 3 wrist positions (60 degrees extension, neutral, and 60 degrees flexion) and 4 carpal tunnel pressures (0, 30, 60, and 90 mmHg). Carpal tunnel pressure was controlled with a balloon angiocatheter inserted deep to the flexor digitorum profundus. The ratio of median nerve to flexor tendon excursion was linear and was affected by wrist position but not carpal tunnel pressure. Patterns of strain in the median nerve proximal to the flexor retinaculum were different from those of strain within the carpal tunnel. Nerve strains were affected by wrist position, but carpal tunnel pressure had no effect. The hydrostatic pressure effect associated with carpal tunnel syndrome does not appear to influence median nerve kinetics or kinematics for the wrist positions studied.

Biomechanical Phenomena↗
PubMed1997

The use of frozen-allograft radial head replacement for treatment of established symptomatic proximal translation of the radius: preliminary experience in five cases.

Five patients with disabling symptoms related to proximal translation (> 1 cm) of the radius following radial head excision (Essex-Lopresti lesion) were treated with implantation of a frozen-allograft radial head prosthesis. Following restoration of neutral ulnar variance at the wrist, a size-matched frozen radial head allograft was implanted and secured to the proximal radius with internal fixation. In three patients, this was a two-stage procedure; radial length was restored gradually using an ilizarov external fixation device and the allograft was placed later. Patients were evaluated clinically and radiographically at a mean follow-up time of 3 years (range, 1-7 years). All patients had relief of wrist and elbow pain and were satisfied with the outcome of the operation. Forearm rotation improved by a mean of 37 degrees and wrist motion improved by a mean of 45 degrees. Forearm reconstruction with frozen radial head allograft implantation may be a beneficial method of treatment for this difficult problem.

Adult↗
PubMed1997

Prevention of unintentional injuries in children.

This is a review article about the past and current approaches to injury prevention in children and recommendations for the future. Orthopaedic physicians who care for children must not only be knowledgeable in the care of musculoskeletal injuries, but must also be familiar with intervention strategies as the focus in medicine shifts from illness to wellness with the emphasis on population-based care.

Accident Prevention↗
PubMed1996

Focal posterior interosseous neuropathy in the presence of hereditary motor and sensory neuropathy, type I.

A 30-year-old male with hereditary motor and sensory neuropathy, type I (HMSN I), presented with asymmetric weakness of finger extension and radial deviation with left wrist extension, previously felt to be a manifestation of the peripheral neuropathy. Nerve conduction studies confirmed HMSN I; however, needle EMG revealed marked, ongoing axonal loss in muscles innervated by the left posterior interosseous nerve (PIN) only. At surgery there was focal fusiform swelling in the PIN at exit from the supinator muscle, compatible with localized hypertrophic neuropathy, which has not been reported before in HMSN I. A concomitant focal mononeuropathy should be considered in cases of hereditary neuropathy with marked asymmetry of weakness.

Adult↗
PubMed1996

Innervation of the lumbrical muscles.

It has long been recognized that the first and second lumbricals are normally innervated by the median nerve, whereas the third and fourth lumbricals are innervated by the ulnar nerve (Sunderland and Ray, 1946). However, the courses of the motor nerves, particularly to the first two lumbricals and their loci of insertion, have not been clearly described. Because this information may be useful to a surgeon operating in the palm, we undertook a cadaver study to define more precisely the pathways of innervation of the lumbrical muscles.

Cadaver↗
PubMed1996

Anatomy of the median nerve at the wrist. Open carpal tunnel release--classic.

An understanding of the normal anatomy of the carpal tunnel and a variety of associated anomalies is important for the physician treating carpal tunnel syndrome. There are many strong arguments for open surgical decompression of the median nerve where full visualization of the transverse carpal ligament and contents of the carpal tunnel can be expected. The authors describe their preferred operative technique and post-operative management for carpal tunnel release.

Carpal Tunnel Syndrome↗
PubMed1995

Early mobilization following carpal tunnel release. A prospective randomized study.

A prospective randomized study was undertaken of 50 consecutive patients undergoing surgery for idiopathic carpal tunnel syndrome to determine the value of splintage of the wrist following open carpal tunnel release. Patients were randomized to either be splinted for 2 weeks following surgery or to begin range-of-motion exercises on the first post-operative day. Subjects were evaluated at 2 weeks, 1 month, 3 months, and 6 months after surgery by motor and sensory testing, physical examination, and a questionnaire. Variables assessed included date of return to activities of daily living, dates of return to work at light duty and at full duty, pain level, grip strength, key pinch strength, and occurrence of complications. Patients who were splinted had significant delays in return to activities of daily living, return to work at light and full duty, and in recovery of grip and key pinch strength. Patients with splinted wrists experienced increased pain and scar tenderness in the first month after surgery; otherwise there was no difference between the groups in the incidence of complications. We conclude that splinting the wrist following open release of the flexor retinaculum is largely detrimental, although it may have a role in preventing the rare but significant complications of bowstringing of the tendons or entrapment of the median nerve in scar tissue. We recommend a home physiotherapy programme in which the wrist and fingers are exercised separately to avoid simultaneous finger and wrist flexion, which is the position most prone to cause bowstringing.

Activities of Daily Living↗