Biomedical subjects

A Biyani

Publications and source records attributed to A Biyani.

At least 37 records · Page 2Linked to original sources

PubMed1996

Zone III fractures of the sacrum. A case report.

STUDY DESIGN: Case reports. OBJECTIVES: To define the radiologic characteristics, management, and results of Zone III fractures of the sacrum. SUMMARY OF BACKGROUND DATA: Zone III fractures of the sacrum are rare. There are few case reports of longitudinal fractures of the sacrum involving Zone III. METHOD: The authors report eight (four transverse, four longitudinal) Zone III fractures of the sacrum. Seven patients were treated surgically by posterior sacral decompression with or without transiliac bar fixation, and one neurologically intact patient with undisplaced longitudinal fracture was treated conservatively. RESULTS: Two neurologically compromised patients had return of normal bladder and rectal function, and another had bladder recovery only. The rest continued to show neurogenic bladder and required intermittent self-catheterization. The patient with bilateral foot drop had partial motor recovery and did not require an ankle-foot orthosis. CONCLUSIONS: These fractures may be difficult to diagnose in polytraumatized patients and require a high index of suspicion. The longitudinal fractures may not be apparent on anteroposterior radiographs, and computed tomography scan may be necessary for establishing the diagnosis. The transverse fractures may show a characteristic step ladder sign on anteroposterior radiographs when the fracture is displaced severely. Proper lateral radiographs often are difficult to obtain, particularly in obese polytraumatized patients. Routine computed tomography scan may overlook the diagnosis. Therefore 2- to 3-mm computed tomography cuts are recommended, which may show double neural foramina in presence of significant anteroposterior displacement and overriding of the fracture fragments. Sagittal computed tomography reconstructions are useful in evaluating the transverse fractures. Posterior sacral decompression is safe and probably promotes nerve root recovery. Longitudinal fractures may be stabilized satisfactorily by transiliac rod fixation.

Adolescent↗

PubMed1996

Vulnerability of great medullary artery.

STUDY DESIGN: The present study describes anatomic observations on great medullary artery and intercostal arteries pertinent to thoracolumbar spinal surgery. OBJECTIVES: This study reveals the vulnerable course of the great medullary artery and its relationship to the lateral or posterolateral approach to thoracic spine. SUMMARY OF BACKGROUND DATA: There are no previous anatomic data on the length of the great medullary artery, its intradural course, its relationship with the anterior spinal artery, and the distance between two adjacent intercostal arteries. METHODS: The location of the intercostal arteries was defined, and the distance between two adjacent arteries was measured at a point on the lateral surface of the vertebra midway between its anteroposterior diameter. The intradural length of the great medullary artery and the angle it formed with the anterior spinal artery at the point of anastomosis were also measured. RESULTS: The mean intradural length of the great medullary artery was 3.6 cm (range, 1.7-8.1 cm), and it passed over 1-3 disc spaces before joining the anterior spinal artery at a mean angle of 20.1 degrees (range, 12-28 degrees). The average distance between two adjacent intercostal arteries from T6 to L2 was 3.6 cm (range, 2.8-4.0 cm), which provides a safe window through which a herniated thoracic disc may be approached if surgery is indicated. CONCLUSIONS: The acute angle between the great medullary artery and anterior spinal artery indicates that these two arteries are in close proximity for considerable length and are liable to be compressed together with the intervening vascular collaterals by a space-occupying lesion, such as disc herniation or a fractured fragment. The longer the intradural course of the great medullary artery, the more vulnerable it is to compression by disc herniation or fracture. The intercostal and lumbar arteries are located at the midportion of the lateral aspect of the vertebral bodies rather than at the level of intervertebral discs. Discectomy or decompression of the anterior thoracic canal may be accomplished through a lateral or posterolateral extracavitary approach between two intercostal or lumbar arteries.

Aorta, Thoracic↗

PubMed1996

An anatomic study of the thickness of the occipital bone. Implications for occipitocervical instrumentation.

STUDY DESIGN: The authors measured the thickness and quality of occipital bone regions to determine screw placement during occipitocervical fusion and described the projection of the posterior dural venous sinuses. OBJECTIVE: This study provides anatomic data relevant to areas of screw placement into the occiput during occipitocervical fixation. SUMMARY OF BACKGROUND DATA: Few reports exist regarding the morphometrics of the occipital bone and intracranial structures relevant to occipitocervical fusion. METHOD: The thickness of the posterior inferior occipital bone was measured relative to a 10 x 5 cm grid. Sections were evaluated grossly and histologically. The projections of the posterior dural venous sinuses were determined by direct measurements. RESULTS: The maximum thickness of the occipital bone, which ranged from 11.5 to 15.1 mm in males and from 9.7 to 12.0 mm in females, was at the level of the external occipital protuberance. The occipital bone was thicker than 8 mm in an area extending laterally from the external occipital protuberance for 23 mm and consisted of dense cortical bone with little or no diploic bone. The projection of most of the torcula on the external surface of the occipital bone was located superior to the center of the external occipital protuberance (mean, 12.6 mm superior and 4.7 mm inferior to external occipital protuberance), whereas that of the transverse sinus was distributed more evenly above and below the external occipital protuberance (mean, 7.3 mm superior and 6.5 mm inferior). CONCLUSIONS: Screws that are 8-mm long may be inserted in the region of the superior nuchal line (Level 0) extending 2 cm laterally from the center of the external occipital protuberance, 1 cm from the midline at a level 1 cm inferior to the external occipital protuberance (Level 1), and 0.5 cm from the midline at a level 2 cm inferior to the external occipital protuberance (Level 2). The major dural venous sinuses are situated immediately beneath the thickest regions of the occiput and are at risk of penetrative injury during screw placement.

Bone Plates↗

PubMed1996

A modified dorsal approach to the wrist for arthrodesis of the non-rheumatoid wrist. An anatomical study.

Fourteen cadaveric wrists were dissected to investigate a modified dorsal approach that involved osteotomy of the small and dorsal tubercles without opening the third compartment. This approach could be safely made with good exposure of the dorsum of the wrist. The mean normal angle formed by the extensor pollicis longus tendon at the level of the dorsal tubercle was 144 degrees. An approach that involves division of the third compartment may lead to effective lengthening of the extensor pollicis longus musculotendinous unit by 8 to 17 mm with corresponding decrease in the tension generated by its contraction. The modified approach permits restoration of the normal alignment of the extensor pollicis longus tendon, and may be useful for performing arthrodesis of the non-rheumatoid wrist in young manual workers.

Arthritis, Rheumatoid↗

PubMed1996

Distribution of nerve fibers in the standard incision for carpal tunnel decompression.

Twenty-two paired biopsy specimens of skin and subcutaneous tissue from the proximal and distal halves of the conventional curvilinear incision or carpal tunnel decompression were histologically examined. The specimens were immunohistochemically stained with S100 antibody to highlight the nerve fibers. The mean count of free nerve endings in the proximal biopsy site was 4.42/mm2 (SD, 2.97; range, 1.23-12.27), compared to 4.2/mm2 (SD, 2.71; range, 1.01-10.50) in the distal biopsy specimens. This difference was not statistically significant (p = .20, Wilcoxon's signed ranks [matched pairs] test). The proximal incision site for carpal tunnel decompression did not appear to be more neuroreceptive than the distal incision site, providing no support for the implication of proximal incision sites in proximal scar tenderness.

Carpal Tunnel Syndrome↗

PubMed1996

Thoracic spine fractures in patients older than 50 years.

The charts and radiographs of 70 patients older than 50 years of age with thoracic vertebral body collapse were reviewed retrospectively. Fifteen patients had traumatic fractures and 34 had osteoporotic collapse of thoracic vertebrae. Metastasis was the underlying disease process in 18 patients and multiple myeloma in the remaining 3 patients. Thirteen patients had fractures involving the upper half of the dorsal spine, of which 8 (61.5%) were metastatic, 4 (30.8%) osteoporotic, and 1 (7.7%) traumatic. All patients with osteoporotic fractures of the upper dorsal spine also had 1 or more fractures of the lower dorsal or lumbar spine. There were 11 metastatic, 80 osteoporotic, 14 traumatic, and 3 fractures secondary to multiple myeloma involving the lower dorsal spine. There were no infections or primary bone tumors. The difference in the frequency of metastatic fractures against other etiologies involving the upper versus the lower thoracic spine was highly statistically significant.

Aged↗

PubMed1996

Optimal technique of screw placement in the ischial tuberosity for posterior acetabular fractures.

Thirty dry adult bony specimens and eight embalmed cadavers were used to report on the morphological data of the ischial tuberosity and to determine the most optimal technique for ischial tuberosity screw placement for open reduction and internal fixation of posterior acetabular fractures. The average width, height, and depth of the ischial tuberosity were 27.0 mm, 32.2 mm, and 32.4 mm, respectively. The average angles between the posterior and medial aspects and between the posterior and lateral aspects of the ischial tuberosities were 79.5 degrees, and 111.5 degrees, respectively. The risk to the internal pudendal neurovascular bundle increases with either a more medially placed screw or a laterally placed screw that is angled medially. The tendinous origin of the hamstrings becomes quite substantial (7-10 mm thick) at a point 2 cm distal to the inferior acetabular margin. The exposure of the ischial tuberosity should therefore be restricted to this level. The entry point of the screws should be 5 mm or 10 mm medial to the lateral margin of the ischial tuberosity, and the screws should be directed 35-40 degrees, 45-50 degrees, and 50-55 degrees caudally at the level of the inferior acetabular margin and 1 cm and 2 cm below it, respectively, to obtain the most favorable bony purchase.

Acetabulum↗

PubMed1996

Incidence, management, and outcome of post-traumatic syringomyelia. In memory of Mr Bernard Williams.

OBJECTIVE: To determine the incidence of clinically diagnosable post-traumatic syringomyelia (PTS). METHODS: A population of 815 consecutive patients with traumatic spinal cord injuries was studied between January 1990 and December 1992. RESULTS: Reviews of all records, full clinical evaluation, and thorough neurological examination of all patients disclosed 28 patients in whom PTS was confirmed radiologically (3.43%). The incidence of the presenting symptoms, including bladder dysfunction, is described. The level and density of cord lesion was correlated with incidence and it was found that posttraumatic syringomyelia was twice as common in patients with complete injuries than in patients with incomplete injuries. The highest incidence was found in patients with complete dorsal and complete dorsolumbar injuries. The interval between injury and diagnosis ranged from six months to 34 years (mean 8.6 years). This interval was shortest in patients with complete dorsal and incomplete cervical and dorsolumbar cord injuries. CONCLUSIONS: Reduction of the size of the syrinx seen on postoperative MRI correlated well with a satisfactory clinical outcome in 85% of patients.

Humans↗

PubMed1996

A pitfall of coronal computed tomographic imaging in evaluation of calcaneal fractures.

Computed tomographic (CT) coronal images of the posterior talocalcaneal joint were compared with lateral radiographic views and intraoperative findings in 35 patients with 36 intra-articular calcaneal fractures. The severity of articular incongruity and rotational displacement of the posterior facet fragment were not well appreciated in coronal CT images of nine patients, although Bohler and Gissane angles were significantly decreased in lateral radiographs. This disparity between the radiographic and coronal CT scans can be explained by the intraoperative finding of rotation of the fractured central or lateral portion of the convex posterior calcaneal facet along a horizontal axis in the coronal plane.

Adult↗

PubMed1996

Calcaneocuboid joint involvement in calcaneal fractures.

The charts and radiographs of 48 surgically treated patients who underwent surgery for calcaneal fractures (right in 25 patients, left in 22, and bilateral in 1) between 1987 and 1994 were retrospectively reviewed. Coronal computed tomographic scans alone were obtained in 33 patients, and both coronal and axial computed tomographic scans were obtained in 9 patients. Three fractures exiting close to the calcaneocuboid joint (CCJ), but not involving the joint, were excluded. Nineteen patients (38.7%) had involvement of the CCJ. The extension of the fracture to the CCJ was apparent in anteroposterior or oblique radiographs or both in 18 patients. There was intra-articular fracture displacement of < or = 1 mm in 6 patients, and 13 patients had a step or a gap of > or = 2 mm with or without angulation. Eleven patients had joint depression type fractures, 6 had tongue type fractures, and 2 had comminuted fractures. Extension of the calcaneal fracture into the CCJ was significantly more common with the joint depression type calcaneal fractures (chi-square test; P = 0.008). The coronal computed tomographic images showed significant lateral subluxation of posterior facet fragments in 8 patients and considerable comminution of the lateral calcaneal wall with or without lateral subluxation of posterior facet fragment in 10 patients. These patients also had CCJ involvement, thus establishing a strong correlation between lateral subluxation of the posterior facet fragment or comminution of the lateral calcaneal wall and CCJ involvement. CCJ involvement is more common with joint depression type fractures. Extension of the fracture line into the CCJ should be suspected in presence of significant lateral column comminution or lateral talar subluxation.

Calcaneus↗

PubMed1996

Computer evaluation of second tarsometatarsal joint dislocation.

Using computer-assisted techniques, this study analyzes the mean contact area of the articular surface of the second tarsometatarsal joint. The articular contact area decreased proportionate to the displacement in both males and females, but it was consistently greater in males than in females for all simulated displacements. The reduction in the contact area was the highest with dorsolateral displacement compared with the lateral and dorsal displacements. Dorsolateral displacement of the second metatarsal of 3 mm led to 38.6% reduction in the contact area, compared with 33.1% and 20.2% reduction with lateral and dorsal displacements, respectively. This study shows that even minor degrees of displacement not apparent on plain radiographs lead to significant decrease in the contact area of the second tarsometatarsal joint. Careful evaluation of second tarsometatarsal injuries with computed tomography is recommended to detect minor degrees of displacement.

Computer Simulation↗

PubMed1996

Vulnerability of vertebral artery in anterolateral decompression for cervical spondylosis.

This study aimed to provide anatomic data for the location of the vertebral artery and offer an optimal approach for lateral cervical decompression that minimizes the risk of injury to the vertebral artery. Anatomically, there has been little study documenting the safe zone to prevent vertebral artery injury during the resection of the uncinate process or uncovertebral joint during the lateral decompression of the nerve root. The transverse foramen and its related parameters were measured on dry cervical spines from C3 to C7. The cadaveric cervical spines were dissected to determine a method for resection of the uncovertebral joint with decreased risk of vertebral artery laceration. The anteroposterior diameters of the transverse foramina gradually decreased from C6 to C3. The transverse diameters of the transverse foramina were smaller at C5. The interforaminal distance, width of the vertebrae, interuncinate distance, and the distance from the lateral tip of the uncinate process to the medial border of the transverse foramen became smaller in more cephalad vertebrae. After subtotal vertebrectomy and opening of the anterior walls of the transverse foramina, the resection of the uncovertebral joint and lateral decompression became easier and safer. Anatomic measurements obtained in this study indicate the vertebral artery to be at risk during decompression of the more cephalad vertebrae. The lateral decompression can be completed under direct vision with smaller rongeurs and curettes, rather than with high speed burr after deroofing the anterior walls of transverse foramina and retracting the vertebral artery laterally.

Adult↗

PubMed1996

Percutaneous pinning of the proximal humerus.

Percutaneous pinning, which has been recommended for unstable, unimpacted two-part fractures of the proximal humerus, requires satisfactory closed reduction and maintenance of reduction with minimum arm movement. Most surgeons usually keep the image intensifier in the anteroposterior (AP) plane and rotate the arm to obtain a second view. This arm movement may render closed reduction and percutaneous pin fixation difficult. A four-step technique that facilitates closed reduction and percutaneous fixation of unstable fractures of the proximal humerus and permits adequate visualization of the proximal humerus in both the AP and axillary planes is presented.

Fracture Fixation, Intramedullary↗

PubMed1996

Anatomic considerations of an anterior approach to the sacroiliac joint.

This anatomic study was performed on 25 disarticulated pelves and 10 embalmed cadavers to evaluate an anterior approach to the sacroiliac joint. The angle of inclination of the superior limb of the sacroiliac joint was 15 degrees superolateral to inferomedial in the sagittal plane, and the inferior limb was parallel to the sagittal plane. The cranial lateral part of the ala overlapped the joint space and the adjacent part of the ilium. Elevation of a rectangular bone block on the cranial part of the ala removed the joint space from the superior limb and provided direct access to the joint space of the inferior limb.

Anthropometry↗

PubMed1996

Anatomic considerations of halo pin placement.

In the present study, the anatomic location of supraorbital and greater occipital nerves and their branches was quantitatively determined with regard to halo pin placement, and a safe zone for anterolateral and posterolateral halo pins was defined to minimize neurologic damage. The mean distance between the midline and the lateral branches of supraorbital nerve and greater occipital nerve was 3.9 +/- 0.4 cm and 4.8 +/- 0.6 cm on the left side and 3.9 +/- 0.5 cm and 4.8 +/- 0.6 cm on the right, respectively. The mean angles of lateral branches of supraorbital and greater occipital nerves with respect to sagittal plane were 26.0 degrees +/- 6.0 degrees and 38.0 degrees +/- 5.0 degrees on the left side and 25.0 degrees +/- 4.0 degrees and 38.0 degrees +/- 4.0 degrees on the right, respectively. The supraorbital and greater occipital nerves and their branches are safe when the halo pins are placed at sites 4.5 cm and 6.0 cm lateral to the anterior and posterior midlines.

Aged↗

PubMed1995

The results of surgical management of displaced tibial plateau fractures in the elderly.

We retrospectively reviewed 32 elderly patients (mean age 71.7 years, range 66-83 years) with displaced tibial plateau fractures after a mean of 3.7 years (range 1-7 years) after operative treatment. Schatzker type 2 fracture was the commonest pattern of fracture (60.3 per cent). According to the modified Rasmussen clinical and radiographic criteria, there were nine excellent, 14 good, five fair and four poor results clinically, and 11 excellent, 12 good, six fair and three poor results radiographically. There was no significant correlation between the final radiographic appearance and clinical outcome. Fourteen patients mobilized postoperatively on a continuous passive motion machine followed by a cast brace had a better result than those mobilized in a cast brace alone, but the difference was not statistically significant (P = 0.29). Postoperative complications included deep vein thrombosis in two patients.

Aged↗

PubMed1995

Fibrous stabilization of the rheumatoid wrist.

19 patients (mean age 59.8 years) underwent fibrous stabilization of the wrist for rheumatoid arthritis. 17 patients were reviewed after a mean follow up of 24.5 months (range 13-40 months). There were four excellent, 11 good, and two poor results according to modified Koka and D'Arcy (1989) criteria. The poor results were due to deep infection in one patient and an unbalanced wrist due to ruptured radial extensors in another. The pre-operative range of wrist movement was an important determinant of the frequency of radio-carpal and/or mid-carpal fusion and the final post-operative range of movement.

Adult↗

PubMed1995

Fractures of the distal radius and ulna.

Associated fractures of the distal ulnar metaphysis were present in 19 of 320 distal radial fractures requiring either closed manipulation or surgical treatment over a 2-year period. Four morphological patterns of ulnar fracture were encountered, the commonest being the type 1 simple extra-articular fracture of the distal end of ulna with minimal comminution (eight out of 19). 15 patients were treated conservatively and two each were treated by internal and external fixation. 15 patients were reviewed after a mean follow-up of 23.8 months and there were four excellent, five good, five fair clinical results and one poor result. Radiographically the distal radio-ulnar joint (DRUJ) was normal in eight wrists, but longitudinal or horizontal disruption of the DRUJ was present in seven wrists. Fracture callus encroached on the DRUJ in three patients, who also had limitation of forearm rotation. Two comminuted ulnar fractures (type 4) developed non-union, but both patients had full forearm rotation, in contrast to restriction of forearm rotation in four out of five patients with type 1 fractures.

Aged↗