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Biomedical subjects

H S An

Publications and source records attributed to H S An.

At least 91 records · Page 5Linked to original sources

The results of operations on the lumbar spine in patients who have diabetes mellitus.

The results for sixty-two patients who had had a diagnosis of diabetes mellitus and lumbar disc disease or spinal stenosis and had been managed with a posterior decompressive procedure were compared, in a retrospective study, with those for sixty-two age and sex-matched non-diabetic (control) patients who had had similar operative procedures. Forty-four of the sixty-two diabetic patients and fifty-five of the non-diabetic patients were available for long-term follow-up (mean, five and seven years, respectively). Among the diabetic patients, there were high rates of postoperative infection and prolonged hospitalization compared with the rates for the control group. The long-term result was excellent or good for seventeen (39 per cent) of the forty-four patients who had diabetes mellitus and for fifty-two (95 per cent) of the fifty-five non-diabetic patients. The poor results in the diabetic patients may have been related to coexisting diabetic neuropathy, to the associated microvascular disease that affects the spinal nerve roots in diabetic patients, or to the failure of the nerve roots of these patients to recover after decompressive procedures.

Adult↗

Noncontiguous injuries of the spine.

A total of 372 consecutive spinal injury patients were evaluated at the Regional Spinal Cord Injury Center of Delaware Valley. Of these, 39 patients (10.5%) were found to have noncontiguous spinal column injuries. Fewer than half of the patients in our series could be classified into previous classification systems (Calenoff, Gupta) of noncontiguous spinal fractures. Fifteen fractures in 12 patients were missed on presentation on admission and 25% of these patients had a progressive neurologic deficit as a result of improper initial immobilization. The location of missed fractures were found to be primarily at the extremes or junctures of the spine (i.e., cervicothoracic, thoracolumbar). Complete spinal roentgenographic evaluation is recommended in the workup of suspected spinal column injury patients, and additional imaging modalities (i.e., tomograms, computed tomography scans, and magnetic resonance imaging) may be necessary in those areas of the spine difficult to visualize.

Adolescent↗

Low lumbar burst fractures: comparison between conservative and surgical treatments.

Twenty-two low lumbar burst fractures (L3-L5) were treated, with an average follow up of 56.2 and 39.0 months in the conservative and surgically treated groups, respectively. Twenty patients were available for review; seven were treated conservatively and 13 were stabilized surgically. All patients were evaluated clinically for work status, activity level, residual pain, and subsequent development of neurologic symptoms. Roentgenograms were reviewed for severity of initial fracture, canal compromise, and maintenance of initial correction. In general, neurologically intact patients in both groups returned to similar postinjury employment levels. Persistent back pain was found to be more disabling in the surgically treated group, in which a fusion incorporating four or five lumbar segments was performed. There was no evidence of significant loss of initial reduction, and no patients experienced late neurological compromise in the surgical group. An average follow-up kyphosis of 9.2 degrees and 31% loss of vertebral height were observed in the conservative group, while a follow-up lordosis of 1 degree and 19% loss of vertebral height were observed in the surgical group. Conservative treatment of low lumbar burst fracture is a viable option in neurologically intact patients, but loss of lordosis and vertebral height may persist. Biomechanical and anatomic characteristics of the low lumbar spine differ from the thoracolumbar region and may account for the inherent stability of these injuries. If surgery is chosen, a long fusion with distraction instrumentation should be avoided in the low lumbar spine. A short rigid fixation with pedicular instrumentation may be of greater benefit.

Adolescent↗

Effects of hypotensive anesthesia, nonsteroidal antiinflammatory drugs, and polymethylmethacrylate on bleeding in total hip arthroplasty patients.

One hundred forty patients ranging in age from 26 to 88 years, who had primary total hip arthroplasty (performed by the same surgeon and lateral surgical approach), were analyzed for intraoperative and postoperative blood loss. The factors affecting blood loss, which include bleeding disorders, medications, duration of surgery, the mean intraoperative blood pressure, and use of cement, were all recorded. A significant reduction in the intraoperative blood loss was observed in the group of patients with hypotensive anesthesia (greater than 20 mmHg drop in the mean intraoperative blood pressure using inhalation anesthetics) compared to the group of patients who did not have hypotensive anesthesia. The patients who had been on aspirin or nonsteroidal antiinflammatory drugs prior to surgery had increased intraoperative and postoperative blood loss compared to the patients who did not take such medications. The effect of cementing with methylmethacrylate on bleeding was also observed; the patients with uncemented implants had a greater blood loss after operation than the patients who had cemented prosthetic components.

Anti-Inflammatory Agents, Non-Steroidal↗

Anatomic considerations for plate-screw fixation of the cervical spine.

A cadaveric study was done to investigate the variability of interfacet distances from C3 to C7, to learn pedicle morphology at C7-T2, and to determine potential dangers of plate-screw osteosynthesis technique of the cervical spine. Twenty-two cadavers were dissected from C2 to C7 to expose the lateral masses and nerve roots. The interfacet distances from the center of the lateral mass to the next lateral mass from C3 to C7 vary widely among different individuals, ranging from 9 mm to 16 (average, 13 mm). A new plate design is necessary to better accommodate the differences in interfacet distances among different patients and different levels. The second part of the study involved 11 dissected cadaveric specimens of the cervicothoracic junction. The pedicle entry point was 1 mm inferior to the midportion of the facet joint for C7, T1, and T2. The medial angulation averaged 34 degrees at C7, 31.8 degrees at T1, and 26.5 degrees at T2. The mediolateral and superoinferior outer pedicle diameters were 6.9 mm and 7.5 mm at C7, 8.5 mm and 9.5 mm at T1, and 7.5 mm and 10.7 mm at T2, respectively. The mediolateral inner diameter averaged 5.18 mm, 6.4 mm, 5.5 mm for C7, T1 and T2, respectively. The pedicle distances (from the entry point to the posterior vertebral body line) measured 9.1 mm, 9.9 mm, and 10.4 mm for respective levels. The margins for error are small when using pedicle screws at these levels. If a pedicle screw must be used at C7, T1, and T2, one must have precise knowledge of the entrance point, diameters, and 25-30 degrees medial direction.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Percutaneous computed tomography stabilization of moderate to severe slipped capital femoral epiphysis.

A percutaneous computed tomography (CT) guided pinning of experimentally reproduced slipped capital femoral epiphysis in five cadavers and one patient--who had bilateral pinning for moderate and severe grade chronic slip--was conducted. Prior investigations of cadavers revealed that this procedure can be performed in selected cases. The details of the technique are illustrated in this article.

Adolescent↗

Differentiation between spinal tumors and infections with magnetic resonance imaging.

Distinction between spinal tumors and infections is a frequent clinical dilemma. To assess the accuracy of magnetic resonance imaging in distinguishing between spinal tumors and spinal infections, 30 patients with proven spinal tumors or infections were studied. Magnetic resonance imaging correctly diagnosed spinal tumors and infections in 29 of 30 cases (97%): 21 of 22 tumors were correctly diagnosed, and 8 of 8 infections were correctly diagnosed. The following points were learned: 1) The most consistent finding of vertebral osteomyelitis was the involvement of the disc space and adjacent vertebral body with decreased signal intensity on the T1-weighted images and increased signal intensity on the T2-weighted images. On the contrary, the disc spaces in tumor cases were uninvolved and demonstrated normal intensities on both T1- and T2-weighted images. 2) Loss of definition of the vertebral endplate was more common with infection than with tumor. 3) Contiguous vertebral involvement was seen more frequently in infections than in tumors. 4) Soft tissue changes were quite helpful: fat planes were obscured diffusely due to edema in infection, whereas fat planes were frequently intact, or obscured only focally, in tumors. 5) Cord compression was accurately diagnosed by magnetic resonance imaging in both tumors and infections. Magnetic resonance imaging was found to be superior to other imaging modalities in its ability to detect tumors or infections early and in providing information on the bone, disc, soft tissue, and neural structures.

Adult↗

Low lumbar burst fractures. Comparison among body cast, Harrington rod, Luque rod, and Steffee plate.

Burst fracture of the low lumbar spine are rare and have not been well delineated in the literature. Thirty-one low lumbar burst fractures (L3-L5) were treated from 1981 through 1989. Average follow-up for 27 of the 31 patients was 46 months. Persistent complaints of back pain seemed to be found more in patients with long instrumentation and fusion and in patients with loss of lordosis. Conservative treatment of low lumbar burst fractures with body cast is a viable option in the neurologically intact patients with minimal height loss and minor angulation. If surgery is chosen, short rigid instrumentation (eg, transpedicular device) is best in accomplishing shorter fusion, maintaining vertebral height, and restoring lumbar lordosis. Harrington distraction rods improve vertebral height but produce loss of lumbar lordosis. Luque rods do not restore vertebral height and are only moderately effective in restoring lumbar lordosis. If patients are neurologically impaired in association with low lumbar burst fractures, posterior decompression by laminotomy or a transpedicular approach is generally effective. Maintaining vertebral height and restoring lumbar lordosis may be important in the prevention of disability from back pain.

Back Pain↗

Gunshot wounds to the cervical spine.

A retrospective review was performed on 28 patients with low-velocity gunshot wounds to the cervical spine. These composed 31% of all spinal gunshot wounds seen during the study period between 1979 and 1988. Surgical decompression did not seem to improve neurologic recovery in either the incomplete or complete patients. Neurologic recovery also appeared to be unaffected by the presence of retained intracanal bullet fragments. The authors found no advantage to routine neck exploration of this penetrating injury. Complications were seen in 93% of the patients. Most complications were thromboembolic, pulmonary, and urinary tract infections. No cases of instability occurred as a direct result of the gunshot wound. No deaths occurred in this series. Two cases of posttraumatic syrinxes were diagnosed. The authors' current treatment recommendations for these patients include selective wound management and observation of retained intracanal bullet fragments in patients with complete lesions. Surgical decompression after this injury is not recommended.

Adolescent↗

Herniated lumbar disc in patients over the age of fifty.

Fifty patients ranging in age between 50-78 years (mean, 56) underwent surgery for a herniated lumbar disc between January 1986 and July 1988. All had objective clinical and radiographic evidence of a herniated disc. All had had failure during an appropriate period of conservative treatment. Far lateral herniation occurred in 8%, and 28% had disc herniations at L2 or L3. Surgical results were 64% excellent, 28% good, 6% fair, and 2% poor. Complications including urinary tract infection, wound infection, myocardial infarction, and pulmonary embolism were observed in 8% of patients. Lumbar disc herniation in the elderly is common. After thorough evaluation to exclude neoplasm or infection, decompression of neural structures can lead to 90% good to excellent results. Spinal stenosis must be carefully considered both preoperatively and intraoperatively. Also, a higher incidence of more cephalad lumbar herniations and far lateral herniations was observed in older patients.

Age Factors↗

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↗

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↗

The value of internal oblique radiographs for posterolateral bone grafting of the tibia.

A 35 degrees internal oblique radiographic view of the tibia was used for the purpose of demonstrating posterolateral tibial bone grafts. This radiograph of the supine patient is made by internally rotating the affected leg 35 degrees obliquely toward the midline. This view eliminates superimposition of both the tibia and fibula on the graft. This method of radiographic evaluation has been found useful in visualization of graft margins intraoperatively and assessing bone graft incorporations in clinical follow-up evaluations. The authors recommend 35 degrees oblique views in preference to anteroposterior and lateral views for patients who have had posterolateral bone grafts of the tibia performed.

Bone Transplantation↗

Cigarette smoking and Dupuytren's contracture of the hand.

Microvascular occlusion has been implicated as a possible causative factor of Dupuytren's contracture. Cigarette smoking is one of the most significant factors in the development of peripheral vasculopathy. The relationship between smoking and Dupuytren's contracture of the hand is explored in this article. One hundred thirty-two consecutive patients who had a partial fasciectomy for treatment of Dupuytren's contracture from 1980 to 1985, were analyzed retrospectively. There were 111 males and 21 females. Ninety (68.2%) of 132 patients smoked cigarettes compared with 110 (37.2%) of 296 randomized hospitalized control patients (p less than 0.00001). Eighty (72.1%) of 111 men smoked cigarettes compared with 65 (44.2%) of 147 male control patients (p = 0.000015). Cigarette smoking is linked statistically to Dupuytren's disease and may be involved in its pathogenesis by producing microvascular occlusion and subsequent fibrosis and contracture or by some other mechanism.

Adult↗