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Biomedical subjects

W T Jackson

Publications and source records attributed to W T Jackson.

At least 109 records · Page 6Linked to original sources
PubMed1990

Incidence of anatomic variants in Guyon's canal.

This study was undertaken to determine the frequency of variations involving the anatomy of Guyon's canal. A series of 58 wrist dissections revealed a 22.4% incidence of anomalous muscles and a 1.7% incidence of anomalous nerve paths. The relationship of the deep branch of the ulnar artery to the superficial and deep branches of the ulnar nerve was found to vary. Accessory muscles passing through Guyon's canal are common, and are often found bilaterally. Aberrant branching of the ulnar nerve in this area is rare.

Humans↗
PubMed1990

Benzophenone dicarboxylic acid antagonists of leukotriene B4. 1. Structure-activity relationships of the benzophenone nucleus.

A series of lipophilic benzophenone dicarboxylic acid derivatives was prepared which inhibited the binding of the potent chemotaxin leukotriene B4 to its receptor(s) on intact human neutrophils. With a radioligand-binding assay as a measure of receptor affinity, a structure-activity relationship for this series was investigated. Both acidic residues were required for receptor-binding activity. The relative orientation of the two acidic groups was important for optimal binding. Replacement of the carbonyl group of the benzophenone with a variety of polar and nonpolar linking groups led to only small changes in binding affinity, indicating the linking group may not be involved in receptor recognition. Further structure-activity relationships within this series are reported in an accompanying paper.

Benzophenones↗
PubMed1990

Benzophenone dicarboxylic acid antagonists of leukotriene B4. 2. Structure-activity relationships of the lipophilic side chain.

A series of lipophilic benzophenone dicarboxylic acid derivatives were found to inhibit the binding of the potent chemotaxin leukotriene B4 (LTB4) to its receptor on intact human neutrophils. Activity at the LTB4 receptor was determined by using a [3H]LTB4-binding assay. The structure-activity relationship for the lipophilic side chain was systematically investigated. Compounds with n-alkyl side chains of varying lengths were prepared and tested. Best inhibition of [3H]LTB4 binding was observed with the n-decyl derivative. Analogues with alkyl chains terminated with an aromatic ring showed improved activity. The 6-phenylhexyl side chain was optimal. Substitution on the terminal aromatic ring was also evaluated. Methoxyl, methylsulfinyl, and methyl substituents greatly enhanced the activity of the compound. For a given substituent, the para isomer had the best activity. Thus the nature of the lipophilic side chain can greatly influence the ability of the compounds to inhibit the binding of LTB4 to its receptor on intact human neutrophils. The most active compound from this series, 84 (LY223982), bound to the LTB4 receptor with an affinity approaching that of the agonist.

Benzophenones↗
PubMed1990

Posterior collicular fractures of the medial malleolus.

The posterior colliculus of the medial malleolus gives origin to the deep part of the deltoid ligament. Posterior collicular fractures are rare injuries, usually nondisplaced due to stabilization by the tibialis posterior and flexor digitorum longus tendons. This nondisplaced fracture is best identified on external oblique radiographs, which are not usually included in standard ankle views. Thus, some index of suspicion is necessary for their detection. A satisfactory result can be achieved by nonoperative treatment of the posterior collicular fracture.

Adult↗
PubMed1990

CT-guided biopsy of metastatic sacral tumors.

Between June 8, 1985 and January 29, 1986, the authors performed five CT-guided needle biopsies of suspicious sacral lesions. In each of the five cases, these biopsies allowed the acquisition of specimens suitable for definitive pathologic diagnosis. Three cases of metastatic adenocarcinoma, one case of desmoplastic fibroma, and one case of chronic inflammatory changes were noted. In the case involving chronic inflammatory changes, subsequent open biopsy was performed, confirming the inflammatory changes and absence of neoplasm. The authors conclude that percutaneous CT-guided biopsy of sacral lesion can be performed safely and rapidly, and allows accurate diagnosis and treatment of sacral lesions.

Adenocarcinoma↗
PubMed1990

Reduction of postoperative CT artifacts of pelvic fractures by use of titanium implants.

The value of CT scanning for both preoperative and postoperative assessment of pelvic and acetabular fractures has been demonstrated. Previous attempts at our institution to obtain useful pelvic CT scans following internal fixation with stainless steel implants have been impaired by metal artifacts that degraded the transaxial CT images. Our use of titanium, instead of stainless steel implants, produced identical fixation and ultimate fracture healing, but yielded minimal artifacts. We recommend the use of titanium implants as substitutes for stainless steel implants in pelvic fixation to maximize the information obtained on subsequent CT exams.

Bone Screws↗
PubMed1990

Bosworth fracture-dislocation of the ankle. A case report and review of the literature.

The Bosworth fracture-dislocation is a rare fracture-dislocation of the ankle where the proximal fibular fragment lodges behind the tibia, rendering it irreducible by routine closed manipulations. Clinically the patient's foot is in severe external rotation. This external rotation makes the initial roentgenograms difficult to interpret. Consequently, the diagnosis is often overlooked, resulting in inappropriate treatment and a disastrous outcome. If properly recognized, these injuries can be successfully treated by closed or open techniques with return of near-normal ankle function. The problem is illustrated in a case involving a 40-year-old woman, as related to a review of the literature and discussion of the treatment rationale.

Adult↗
PubMed1990

Posterolateral bone graft of the tibia.

A series of 30 high-energy tibial diaphyseal fractures in 30 patients were treated with posterolateral bone grafting (1984-1987). All of the fractures were open, a majority being Gustillo Type III with significant soft-tissue injury, comminution, or segmental bone loss. The common mechanisms of injury included motorcycle, pedestrian versus automobile, and motor vehicle accidents. Nineteen of 30 fractures were treated with a posterolateral bone graft within six months of the initial injury, and 11 of 30 were grafted after established nonunion. Union was obtained in 29 of 30 fractures (97%). Healing time from the time of grafting ranged from three to 12 months, with an average of 4.7 months. One patient had a below-knee amputation because of uncontrolled chronic osteomyelitis, drainage, and nonunion. Posterolateral bone grafts consistently produced rapid healing of delayed union as well as established nonunion.

Adult↗
PubMed1989

"Interventional angiography." A possible role in intraoperative balloon occlusion catheterization of lacerated pelvic arteries.

The use of interventional angiography has been limited in the past to the angiography suite. Significant technical difficulties have been associated with transfer of the unstable patient from the operating room for this procedure. However, current radiographic sophistication now exists to allow rapid intraoperative digital subtraction angiography of uncompromised quality to be performed. An animal model using these techniques is presented.

Angiography↗
PubMed1989

Magnetic resonance imaging in the evaluation of a gunshot wound to the cervical spine.

A patient in the second trimester of pregnancy sustained a gunshot wound of the upper cervical spine with a partial Brown-Séquard syndrome. The patient's condition was evaluated by conventional roentgenography, computed axial tomography (CT), and magnetic resonance imaging (MRI). The MRI alone clearly demonstrated the relationship of the bullet and the spinal cord, whereas the CT image was obliterated by metal artifacts. The bullet was removed from the spinal canal by a posterior approach with the patient in the sitting position and in skeletal cervical traction. The neurological status of the patient improved markedly after the surgery.

Adult↗
PubMed1989

Internal fixation of the unstable cervical spine using posterior Roy-Camille plates: preliminary report.

We reviewed 13 cases of unstable cervical spine treated by stabilization with posterior Roy-Camille plates and fusion. The patients were treated between 1985-1988. Six patients had acute traumatic episodes, three patients had posttraumatic instabilities, one patient had laminectomy for cervical spondylotic myelopathy, and three patients had metastatic bone disease. All had successful fusion in approximately 3 months without complications. The indications and techniques of posterior Roy-Camille plating are outlined.

Adult↗
PubMed1989

Three-dimensional computed tomography in evaluation of occipital condyle fracture.

Fracture of the occipital condyle is a rare sequela of craniocervical trauma. The diagnosis can be suspected in an injured patient with disproportionate torticollis, uncertain evidence of subluxation, and lower cranial nerve symptoms. Standard radiographic diagnosis of this fracture is difficult owing to its superimposition on other bony structures. Film tomography or computed tomography (CT) is usually required to identify the fracture. We report a case of occipital condyle fracture initially masked by atlantoaxial subluxation, but then best demonstrated by three-dimensional CT.

Aged↗
PubMed1989

Radiological diagnosis of screw penetration of the hip joint in acetabular fracture reconstruction.

Screw penetration of the hip joint following acetabular fracture reconstruction is a relatively uncommon complication but, if not corrected, may have a catastrophic effect on the postoperative function of the hip joint. Intraoperative radiographs and postoperative standard anteroposterior (AP) radiographs frequently show super-imposition of the screws and acetabulum. Computed tomographic (CT) scanning has been the only diagnostic technique available allowing documentation of screw penetration into the hip joint. CT scan, however, can be performed only after termination of surgery. In search for a radiological view that will help in diagnosing screw penetration into the hip joint both intra- and postoperatively, we undertook a controlled study of 25 patients having either a posterior or extensile lateral surgical approach and six cadaveric specimens. A combination of a cross-table lateral view of the hip and a Judet iliac view proved more informative than AP or Judet obturator views in demonstrating absence or presence of the screw in the hip joint (if the screws were placed along the posterior wall or column). Intraoperative AP radiographs projected as a Judet obturator view were the least helpful in making this determination. When screw penetration is suspected, we recommend the use of intraoperative fluoroscopy in multiple projections or intraoperative arthrogram in the lateral projection of the pelvis. Also, Judet iliac and cross-table lateral radiographs in the operating room while the patient is still under anesthesia might exclude any screw penetration into the hip joint.

Acetabulum↗
PubMed1989

Anterior and posterior cervical spine fixation using titanium implants to facilitate magnetic resonance imaging evaluation.

Magnetic resonance (MR) imaging of the cervical spine is useful in the evaluation of both acute and chronic injuries to the spinal cord and meninges as well as in demonstration of mechanical impingement on the spinal canal and nerve roots. Anterior or posterior plate fixation of unstable cervical spine injuries has limited the postoperative use of MR imaging due to the extensive magnetic field distortion produced by the stainless steel implants commonly used in these procedures. We have compared titanium implants in a cadaver against stainless steel implants in two patients and show no significant MR artifacts produced in the spinal canal by titanium plates as opposed to extensive image distortion and obliteration by the steel plates. We recommend consideration of titanium (Ti6A14V) as a substitute for stainless steel in cervical spine fixation to preserve the option of subsequent examination by MR scanning.

Bone Plates↗
PubMed1989

Assessment of collicular fractures of the medial malleous.

Collicular fractures of the medial malleolus have been described in literature as early as 1950 by Bonnin and then by Pankovich in 1979, yet have been given relatively little attention in orthopaedic and radiologic literature. A precise knowledge of the anatomy of the deltoid ligament, and anterior and posterior colliculi in relation to obtained radiographs is important in the determination of whether a fracture is considered to be stable or unstable, and thus bears an impact on its treatment. The intent of this discussion is to review the structures which comprise the medial malleolus and the assessment of their involvement in acute injury.

Ankle Injuries↗
PubMed1989

Anatomic relations between the median nerve and flexor tendons in the carpal tunnel: MR evaluation in normal volunteers.

To ascertain the dynamic changes between the median nerve and flexor tendons in the carpal tunnel, MR images of 16 wrists in eight volunteers were studied in flexion, extension, and neutral positions. T1-weighted axial images, 600/20 (TR/TE) were obtained with the wrists straight, extended at 45 degree, and flexed at 45 degree. Each scan was evaluated with regard to positional changes of the median nerve and flexor tendons in the carpal tunnel as well as alterations in nerve shape. In the neutral position, the median nerve was found in one of two standard positions: either anterior to the superficial flexor tendon of the index finger or interposed more posterolaterally between this tendon and the flexor pollicis longus. During extension, the nerve always maintained or assumed an anterior position between the superficial index finger flexor and the flexor retinaculum, while the flexor tendons moved posteriorly. With flexion, the tendons shifted anteriorly toward the retinaculum, and the median nerve was found in one of three positions. It either remained in its anterior position between the superficial index finger flexor and retinaculum or became interposed between the superficial flexor tendons of the index finger and thumb or middle finger and ring finger. Nerve shape varied with its position. Anteriorly positioned nerves were flattened in the anteroposterior plane between the tendon and flexor retinaculum; this was greatest with flexion and least with extension. Interposed nerves were flattened in the mediolateral plane or rounded in configuration. In conclusion, the alignment of the median nerve in the carpal tunnel, its shape, and its relationship to the flexor tendons were variable and dependent on wrist positioning. These findings may explain why certain wrist motions, flexion in particular, predispose a person to carpal tunnel syndrome.

Adult↗