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Biomedical subjects

R A Berger

Publications and source records attributed to R A Berger.

At least 19 recordsLinked to original sources
PubMed1996

The capitohamate ligaments. A comparison of biomechanical properties.

The physical attributes of the three capitohamate interosseous ligaments were tested in a computer-controlled multi-axis testing machine using 12 human cadaver specimens. After an intact test run, selected ligaments were cut in random sequence and the test repeated. The remaining ligaments were tested to failure with servohydrolic stress at 5 mm/second. In the intact joint complex, the average dorsopalmar rotational displacement was approximately 9 degrees in each direction. Under the load limit, the dorsopalmar translational displacement averaged 0.9 mm and 0.5 mm respectively, proximal-distal translational displacement averaged 0.8 mm and 0.4 mm respectively, and distractional displacement averaged 0.3 mm. Based on the sequential sectioning it was found that the dorsal ligament provided 76% (SD 14) of the rotational resistance with palmar rotation of the capitate and 44% (SD 19) of translational constraint with palmar translation of the capitate. The deep ligament provided 51% (SD 15) of the rotational resistance with dorsal rotation of the capitate and 63% (SD 24) of translational resistance with dorsal translation of the capitate. With proximal-distal translation, the dorsal ligament was the most important constraint in each direction. In resisting distraction, each of the three ligaments was equally effective. Failure testing showed the deep ligament was strongest at 289 N, followed by the palmar at 171 N and the dorsal at 133 N.

Adult↗
PubMed1996

The gross and histologic anatomy of the scapholunate interosseous ligament.

The scapholunate interosseous ligament, which connects the carpal scaphoid and lunate bones, was evaluated by gross dissection and serial histologic sections in transverse, sagittal, and coronal planes in 21 fresh and 16 fixed adult cadaver wrists. The scapholunate interosseous ligament is consistently divisible into three anatomic regions: dorsal, proximal, and palmar. The dorsal region is thick and composed of short, transversely oriented collagen fibers. The proximal region is principally composed of fibrocartilage, with a few superficial, longitudinally oriented collagen fibers. The proximal region may extend distally a few millimeters into the scapholunate joint space, thus resembling a knee meniscus. The radioscapholunate ligament separates the proximal and palmar regions of the scapholunate interosseous ligament, often extending distally to cover the dorsal surface of the palmar region of the scapholunate interosseous ligament. The palmar region is thin and composed of obliquely oriented collagen fascicles, just dorsal to and separate from the long radiolunate ligament.

Adult↗
PubMed1995

The arterial blood supply of the distal radius and ulna and its potential use in vascularized pedicled bone grafts.

We investigated the extra- and intraosseous blood supply of the distal radius and ulna (descriptive anatomy) and defined potential vascularized pedicled bone grafts to the carpal bones (applied anatomy). We studied 41 cadaver upper limbs using several techniques including angiography, Batson's compound and latex injections, and bone clearing using a modified Spalteholtz technique. Several known arteries were described in greater detail, and numerous previously undescribed arteries were found and investigated. Vascularized pedicled grafts have potential applicability for carpal pathology. Several grafts have been described from the radius, second metacarpal, and pisiform. We have identified several vascular pedicles that provide the hand surgeon with additional options. Some of these grafts provide a wider arc of rotation, greater ease of harvest and/or improved vascularity compared to many previously described grafts.

Adult↗
PubMed1995

New dorsal capsulotomy for the surgical exposure of the wrist.

A reliable, safe approach to the wrist through fiber-splitting dorsal capsulotomies has been developed. The dorsal wrist capsule is exposed by subperiosteally elevating the fourth and fifth extensor compartments ulnarly and translocating the extensor pollicis longus tendon with the radial wrist extensor tendons radially. The midcarpal joint and the radial half of the radiocarpal joint are exposed by longitudinally splitting the dorsal radiocarpal and dorsal intercarpal ligaments, with the apex at the triquetrum. The flap created is elevated radially, detaching the dorsal capsule from the radius to the level of the styloid process. For exposure of the ulnocarpal joint, the dorsal radiocarpal ligament is split longitudinally, and the capsule is incised along the extensor carpi ulnaris tendon subsheath proximally to the level of the triangular fibrocartilage, with the apex at the triquetrum. The flap created is elevated proximally. Exposure of the wrist is excellent, stability of the carpal bones is maintained, and closure is simplified using this approach.

Carpal Bones↗
PubMed1995

Vitamin A capsule supplementation in Malawi villages: missed opportunities and possible interventions.

A population-based survey was used to assess childhood and maternal vitamin A capsule coverage in Malawi and to investigate missed opportunities for capsule distribution. Overall, 9.3% of children had received vitamin A supplementation in the previous 6 months. Missed opportunities for receiving vitamin A were high in younger children. Fifty-five percent of mothers were covered in 8 villages served by volunteers and 23% in the 58 villages without volunteers. Existing strategies need to be redesigned and new strategies defined. For instance, mothers could receive supplementation during infant BCG vaccination, and children could receive initial supplementation during measles vaccination. Village health volunteers could be used to target children over 2 years of age.

Child Nutritional Physiological Phenomena↗
PubMed1995

Arthroscopic anatomy of the wrist.

A good working knowledge of the intra-articular anatomy of the wrist is essential to perform arthroscopy. The authors present a detailed description of all pertinent structures that may be seen during a radiocarpal and midcarpal arthroscopic examination.

Arthroscopy↗
PubMed1994

Predicting palmar radio-carpal ligament disruption in fractures of the distal articular surface of the radius involving the palmar cortex.

12 adult cadaver wrists were dissected to identify the regions of origin of the four palmar radio-carpal ligaments. A non-dimensionalized value, called the radio-carpal ligament ratio (RLR), was defined as the width of ligament origin from the radius divided by the length of the capitate. Both values were measured directly from radiographs of the cadaver specimens. The RLRs for the four palmar radio-carpal ligaments were found to be statistically consistent. We applied the RLR concept retrospectively to 20 wrists with intraarticular distal radius fractures requiring open reduction. It was found that those fracture patterns in which the fracture fragment ratios (FFR: widths of the fracture fragments divided by the length of the capitate) were outside the limits of corresponding RLRs had clear intra-operative evidence of palmar radio-carpal ligament disruption, while those with FFRs within the limits of corresponding RLRs were noted to have no ligament disruption.

Adult↗
PubMed1994

Lumbrical muscle incursion into the carpal tunnel during finger flexion.

Carpal tunnel syndrome is one of the many so-called cumulative trauma disorders thought by some to be related to the performance of repetitive tasks in the work-place. The cause of this disorder is unknown. We have observed lumbrical muscle incursion into the carpal tunnel during finger flexion. This study was conducted to determine the amount of this incursion in normal wrists. Five cadaver upper limbs were analyzed radiographically with radiopaque markers on the flexor retinaculum and the lumbrical muscle origins in four finger positions: full extension, 50% flexion, 75% flexion, and 100% finger flexion. The lumbrical muscle origins were an average of 7.8 mm distal to the carpal tunnel in full finger extension. They moved an average of 14 mm into the carpal tunnel with 50% finger flexion, 25.5 mm with 75% flexion, and 30 mm with 100% flexion. Abnormal lumbrical muscles have been cited as a possible cause of carpal tunnel syndrome. These findings suggest that lumbrical muscle incursion during finger flexion is a normal occurrence and is a possible cause of work-related carpal tunnel syndrome.

Carpal Bones↗
PubMed1994

Magnetic resonance imaging of the anterior radiocarpal ligaments.

Magnetic resonance imaging was applied to eight cadaver wrists to evaluate the efficacy of imaging the anterior radiocarpal ligaments. In order to verify a correlation between the magnetic resonance images and anatomic structures, ancillary studies using gadolinium-DTPA ligamentography and gross sectioning of the specimens were performed. The ligaments targeted for evaluation were the radioscaphocapitate, long radiolunate, and short radiolunate ligaments. The highest resolution images were obtained using a 1.5 Tesla magnetic resonance imaging scanner and a surface coil applied to the wrist region, and producing T1-weighted images, with 3 mm thick sections with an 8 cm field of view. The radioscaphocapitate, long radiolunate, and short radiolunate ligaments were most consistently identified in sagittal planes, however they were also identified in coronal planes. The radioscapholunate ligament and the interosseous ligaments between the scaphoid, lunate, and triquetrum were most consistently identified in coronal planes. Transaxial planes provided consistently inferior views, and should be reserved for imaging of the flexor and extensor retinaculae.

Adult↗
PubMed1994

The effects of nonswimming water exercises on older adults.

Exercise in a water medium reduces weight-bearing stresses on the skeletal joints, which may be advantageous for older individuals needing rehabilitation. The purpose of this study was to determine the effects of nonswimming exercises on muscle endurance, % body fat, and aerobic work capacity of an older adult population. Twelve subjects were in an exercise group (10 females and two males), and eight were in a control group (five females and three males). The mean ages of the groups were 65 (+/- 5.29) years and 56 (+/- 6.78) years, respectively. Before and after 12 weeks of training, subjects were measured three times weekly for resting heart rate, maximum heart rate, VO2 max, body composition, and work capacity in water. A general linear model ANCOVA was used with age as the covariate. The exercise group improved significantly (p < .05) on all dependent variables examined except body composition after 12 weeks. However, the control group experienced no significant changes on any variable over this period. In the comparisons between groups, the exercise group significantly surpassed the control group on all variables except body composition, where neither group experienced change. Nonswimming exercises appear to be a viable and effective means to improve cardiorespiratory function and physical work capacity of the elderly.

Aged↗
PubMed1994

Endoscopic carpal tunnel release. A current perspective.

Carpal tunnel syndrome is defined as a clinical condition related to dysfunction of the median nerve specifically related to the carpal tunnel. This article reviews anatomy, current surgical treatment options, technique, indications and contraindications, efficacy, complications, and the author's own perspective on the subject.

Arthroscopy↗
PubMed1993

Preventing distal voids during cementation of the femoral component in total hip arthroplasty.

Cement voids have been noted in close approximation to the unfilled hole in the distal end of the femoral prosthesis. These cement voids result from the displacement of cement by the expansion of air trapped in the distal prosthesis. Voids in the distal cement have been shown to lead to an increased incidence of cement failures. This potentially deleterious situation can easily be avoided by plugging the hole in the distal stem. This may be accomplished three ways: using a centralizer, using the plastic plug supplied with the prosthesis, or filling the hole with cement prior to implanting the prosthesis.

Cementation↗
PubMed1993

Influence of sex, presentation order, and trial blocks on young adults' simple and type-C reaction times.

This research examined the influence of sex, presentation order, and trial blocks on young adults' reaction times (RTs). Right-handed men and women (n = 56) completed 20 simple and 40 type-c RT trials. Analysis of variance indicated that men reacted faster than women and that the simple task was performed more quickly than the type-c version. The significant interaction for type of task x trial blocks indicated that simple RTs became faster and type-c RTs slowed from the initial to subsequent trial blocks. The significant interaction for type of task x presentation order indicated that type-c task performance was quicker when administered first. Analysis of variance also showed that false positive errors on the type-c task were most frequent during the first trial block.

Adult↗
PubMed1993

Treatment of complex fractures of the distal radius. Combined use of internal and external fixation and arthroscopic reduction.

A group of fractures of the distal radius are inherently unstable and cannot be treated by closed reduction and cast or external fixation. These fractures are high-energy motor vehicle accidents often seen in young adults but possible in nearly every age group. They are not typical Colles's fractures because they are intra-articular with displacement of the joint articular surfaces. The goals of treatment are to obtain an anatomic reduction and then to proceed with treatment techniques to maintain the reduction by whatever methods are available or necessary within the experience of the treating surgeon. Previous admonitions that Colles's fractures should not be treated by open reduction are incorrect. Like other intra-articular fractures, the goal is anatomic alignment. Limited open reduction or newer arthroscopic techniques may be sufficient. A more aggressive approach of open reduction, internal and external fixation, and autogenous bone grafting is now indicated in most high-energy distal radius fractures to achieve the treatment goals defined earlier: anatomic joint surface reduction, restoration of radial length, and correction of dorsal malangulation.

Adolescent↗
PubMed1993

Determining the rotational alignment of the femoral component in total knee arthroplasty using the epicondylar axis.

The posterior condylar surfaces of the femur are routinely used as the reference for the rotational orientation of the femoral component during most primary total knee arthroplasties. The purpose of this investigation was to identify a clearly discernible, reproducible secondary anatomic axis useful for determining the rotational orientation of the femoral component when the posterior condylar surfaces cannot be used. Seventy-five embalmed anatomic specimen femurs were studied. A surgical epicondylar axis was defined as the line connecting the lateral epicondylar prominence and the medial sulcus of the medial epicondyle. The posterior condylar angle was measured as the angle between the posterior condylar surfaces and the surgical epicondylar axis. Measurement of the posterior condylar angle referenced from the surgical epicondylar axis yielded a mean posterior condylar angle of 3.5 degrees (+/- 1.2 degrees) of internal rotation for males and a mean posterior condylar angle of 0.3 degree (+/- 1.2 degrees) of internal rotation for females. Thus, rotational alignment of the femoral component can be accurately estimated using the posterior condylar angle. The posterior condylar angle, referenced from the surgical epicondylar axis, provides a visual rotational alignment check during primary arthroplasty and may improve alignment of the femoral component at revision.

Biometry↗
PubMed1993

Avoiding neurologic and vascular injuries with screw fixation of the tibial component in total knee arthroplasty.

This investigation determined the position of neurologic and vascular structures at risk during screw fixation of an uncemented tibial component in total knee arthroplasty relative to the cut surface of the tibial plateau. Sixteen anatomic specimens of the lower extremities were studied by systematically placing screws about the tibial plateau followed by computed tomographic scanning with three-dimensional reconstruction and anatomic dissection. The structures at risk during screw preparation and placement were the tibial nerve, popliteal artery, popliteal vein, anterior tibial artery, and common peroneal nerve with its superficial and deep branches. The application of a clock system to the cut surface of the tibial plateau with the six o'clock position defined as directly anterior and the three o'clock position defined as lateral identified the entire region between the 11 o'clock and three o'clock positions as a location where potential injury to vital structures can occur during screw placement. The risk of injury to these structures may be minimized by directing screws radially inward to avoid violation of the tibial cortex. Any penetration of the cortex between the 11 o'clock and three o'clock positions may have potentially devastating consequences because of the close proximity of neurologic and vascular structures.

Blood Vessels↗
PubMed1992

[Severe tricuspid valve insufficiency due to papillary anterior muscle infarction of the right ventricle secondary to neonatal hypoxia].

A fatal case of a stressed newborn baby who developed tricuspid insufficiency due to an anterior papillary muscle infarction of the right ventricle, related to perinatal anoxia is reported. The baby needed resuscitation management and had a systolic murmur soon after birth. The echocardiographic examination showed a flail anterior leaflet of the tricuspid valve due to an avulsed anterior papillary muscle. There was rupture of chordae tendineae between anterior and posterior leaflet. Necrosis and calcium deposit were found in the area. The conclusion was that the anoxia in perinatal period, in most cases, causes transient lesions, but in few cases might be severe and fatal. It is important a complete cardiac evaluation in every case of prolonged perinatal stress.

Echocardiography, Doppler↗