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Biomedical subjects

D A Bednar

Publications and source records attributed to D A Bednar.

At least 19 recordsLinked to original sources
PubMed1997

Procurement of bone graft from the iliac crest. An operative approach with decreased morbidity.

We compared the donor site morbidity in fifty-seven consecutive patients in whom a bone graft had been procured from the iliac crest through an incision parallel to the superior cluneal nerves and perpendicular to the posterior iliac crest (the study group) with that in fifty-three consecutive patients in whom the graft had been procured through an oblique incision parallel to the posterior iliac crest (the control group). Numbness, tenderness, and pain at the donor site one and six months postoperatively were assessed by means of an interview with the patient and a review of the records. The prevalence of symptoms in the control group was greater than that in the study group. At one month, thirty-nine patients (74 per cent) in the control group had numbness, compared with twenty-five (44 per cent) in the study group (p = 0.001). At six months, thirty-one patients (58 per cent) in the control group had numbness, compared with fourteen (25 per cent) in the study group (p = 0.0002). Thirty-six patients (68 per cent) in the control group and twenty-four (42 per cent) in the study group had tenderness over the incision at one month (p = 0.005), and twenty-seven (51 per cent) and eleven (19 per cent), respectively, had tenderness at six months (p = 0.0003). Forty patients (75 per cent) in the control group and forty-six patients (81 per cent) in the study group had deep pain in the region of the iliac crest at one month, compared with thirty-two (60 per cent) and thirty-one (54 per cent), respectively, at six months. The mean analog score for pain at the donor site was 7 of 10 points in the control group and 6 points in the study group (p = 0.001) at one month and 3 and 2 points, respectively, at six months (p = 0.001).

Activities of Daily Living↗
PubMed1996

New insight into the mechanics of the lumbar interspinous ligament.

STUDY DESIGN: Repeated in vitro mechanical tests were performed on porcine and human interspinous ligament specimens with progressive disruption of the collagen fiber network to evaluate the existence of mechanical interactions between collagen fibers. OBJECTIVE: To evaluate the existence of a load pathway in the interspinous ligament whereby loads are transmitted between collagen fibers. SUMMARY OF BACKGROUND DATA: Mechanical tests demonstrate that the interspinous ligament resists spinal flexion, but the collagen fibers are not oriented to oppose separation of the spinous processes. This seeming contradiction could be explained by the existence of mechanical interactions between collagen fibers of the interspinous ligament. METHODS: In vitro mechanical tests were performed on porcine and human bone-interspinous ligament-bone specimens. The collagen network of the ligament substance was disrupted by passing a scalpel blade though the ligament substance. Repeated tests were performed with progressive disruption of the collagen fiber network. RESULTS: The stiffness of the interspinous ligament specimens was reduced as the collagen fiber network was disrupted, but approximately half of the initial stiffness was maintained when the collagen fiber network was severely disrupted. In this case, no intact collagen fibers remained. CONCLUSIONS: Mechanical interactions exist between collagen fibers in the interspinous ligament. The mechanism of the interactions is unknown.

Animals↗
PubMed1996

External spinal skeletal fixation in the management of back pain.

External spinal skeletal fixation, pioneered by the Association for the Study of Internal Fixation as an alternative in thoracolumbar fracture management, has been effective in temporarily relieving mechanical low back pain. This investigational technique was been proposed as an alternative in the selection of patients with back pain as candidates for pain relief through fusion. This is the report of a prospective and randomized clinical trial that has defined prognostic benefit (good outcome in 61% of control patients versus 90% of the study group) in selecting patients with mechanical back pain (verified through facet blocks or discograms) as candidates for pain relief through fusion surgery.

Adult↗
PubMed1995

Identifiable risk factors for secondary neurologic deterioration in the cervical spine-injured patient.

STUDY DESIGN: This was a retrospective prevalence study. OBJECTIVE: A review of structural cervical spine injuries (fracture or dislocation) treated at a regional spine injury referral center from 1987 to 1992 was undertaken to identify and analyze patients who had secondary neurologic deterioration after they had arrived and had primary assessment in stable neurologic condition (intact or compromised, but not evolving). SUMMARY OF BACKGROUND DATA: Multiple case reports and cohort studies have suggested possible risk factors for late neurologic deterioration without probabilities analysis. METHODS: Information was obtained retrospectively from clinical records and radiographs. Three-hundred-twelve cases were reviewed. Thirty-one were excluded and 281 were analyzed. RESULTS: An index group of 15 patients (5%) had motor neurologic deterioration after primary assessment at the referral center. Control group "A" was composed of 70 patients (25%) who had a motor neurologic deficit on admission and did not deteriorate. Control group "B" was the balance of 196 patients (70%) with structural cervical injuries, but no neurologic compromise. Factors distinguishing the index group from control subjects included flexural mechanism of injury and chronic multilevel spinal arthritis with ankylosis. All secondary deteriorations occurred with the injury level caudad to the fourth cervical vertebra. Routine three-view cervical radiographs were relatively insensitive in detecting injury in the index group compared with the pooled control subjects. Patients' ability to comply with recommended treatment was not a factor in secondary deteriorations and there generally was no identifiable precipitant event before secondary deterioration. CONCLUSION: Cervical traumatized patients with flexural injury or chronic multilevel spinal arthritis with ankylosis are at increased risk of having secondary motor neurologic deterioration.

Adult↗
PubMed1995

Observations on the pathomorphology of the thoracolumbar fascia in chronic mechanical back pain. A microscopic study.

STUDY DESIGN: Human tissue specimens were examined for the presence of neural end-organs under light and electron microscopy. OBJECTIVES: To define the innervation of the thoracolumbar fascia in problem back pain patients who have articular abnormality defined through pain-provocation discography or facet blocks. SUMMARY OF BACKGROUND DATA: Previous investigators have defined the presence of innervation in control (no back pain) tissue specimens. METHODS: Tissue specimens were harvested during surgery from 24 back pain patients who had not undergone previous lumbar surgery. Specimens were fixed immediately in the operating room and later processed and studied under light and electron microscopy. RESULTS: Structural and ultrastructural studies failed to identify specific neural end-organs in any of the specimens. Serendipidously, microscopic changes suggestive of ischemia or inflammation in this tissue were found. CONCLUSIONS: These findings suggest that the thoracolumbar fascia may be deficiently innervated in problem back pain patients.

Back Pain↗
PubMed1995

Management of type II odontoid process fractures in geriatric patients; a prospective study of sequential cohorts with attention to survivorship.

After institutional review defined an unacceptable mortality rate in nonoperative treatment of elderly patients with odontoid process fracture without neurological deficit, we undertook a prospective study to determine the influence of early surgical stabilization on perioperative mortality in geriatric odontoid process fracture patients without neurologic injury. Analysis suggests that acute perifracture mortality in this high-risk group can be significantly decreased and potentially eliminated by this approach.

Aged↗
PubMed1993

Intramedullary nailing of femoral shaft fractures: reoperation and return to work.

OBJECTIVE: To define the functional outcome and residual disability in adults treated for isolated femoral shaft fractures. DESIGN: A retrospective case study of HMRI records. The mean follow-up was 34.5 months from the time of injury. SETTING: A tertiary-care teaching hospital. PATIENTS: One hundred and thirty adults with femoral shaft fractures. Of these, 47 were isolated and qualified for study. INTERVENTIONS: Primary reamed intramedullary nailing performed between April 1987 and September 1990. MAIN OUTCOME MEASURES: Reoperation and return to work. RESULTS: Of the 47 patients, primary healing occurred in 41 (87%) patients; 6 (13%) patients had delayed union or nonunion. Twenty (43%) patients had delayed implant-related pain after fracture healing; 85% of these had relief of pain after implant removal. Of 41 patients available for analysis of function based on return to work, 33 (80%) had returned to work full time in their original occupation at the time of follow-up, and 4 (10%) were working in other full-time employment; 3 (7%) were working part time. Only one (2%) patient was disabled and unable to work. CONCLUSIONS: Primary reamed intramedullary nailing is an effective method of achieving consistent primary union in adults with femoral shaft fractures. However, the majority of patients will require secondary surgery. Most patients will be able to return to work after these injuries.

Adult↗
PubMed1993

Anterior and posterior spinal fusion: comparison of one-stage and two-stage procedures.

OBJECTIVE: To compare postoperative morbidity and length of hospital stay after combined anterior and posterior spinal fusion for patients treated by a one-stage procedure and those treated in two stages, 1 to 2 weeks apart. DESIGN: Retrospective review of all cases handled by the first author between July 1989 and November 1991. The patients had been referred for treatment of severe spinal deformity, scoliosis or kyphosis by combined anterior and posterior spinal fusion. SETTING: The operations were performed at McMaster University Medical Centre, Hamilton, Ont., by the first author, who was assisted by another specialist in spinal surgery and a fellow or resident. PATIENTS: Eleven operations of each type were performed. The mean age of the 22 patients was 16.6 and 14.6 years for those who underwent the one-stage and the two-stage procedures respectively. The diagnoses included neuromuscular disease, neurofibromatosis, spina bifida, congenital kyphoscoliosis and severe idiopathic spinal curvature. The one-stage procedure was used after the surgical team became able to provide the care associated with this type of major surgery; selection of patients also involved preoperative risk assessment and the feasibility of combining two surgical procedures that would take a maximum of 9 hours. The preoperative plan was to spend a maximum of 9 hours in performing the one-stage procedure. INTERVENTIONS: Similar surgical procedures were performed in both groups. The average number of intervertebral levels fused during the anterior component of the operation was 4.6 in the one-stage procedure and 6.0 in the two-stage procedure. Thoracolaparotomy was performed in four patients who underwent the two-stage procedure. During the posterior component of the operation, instrumentation was inserted through an average of 11.6 and 12.6 intervertebral levels in the groups undergoing the one-stage and the two-stage procedures respectively. Total operating time averaged 7 hours and 15 minutes for the one-stage procedure and 11 hours for the two-stage procedure. Mean blood loss was 1830 mL for the one-stage procedure and 2270 mL for the two-stage procedure. MAIN OUTCOME MEASURES: The number of days spent in the intensive care unit (ICU) and the total number of days spent in hospital, as well as morbidity after the operation, were determined. RESULTS: Postoperative morbidity included five minor complications in patients who underwent a one-stage procedure; all of these complications resolved well. Among those who underwent the two-stage procedure there were 11 complications; in two patients further surgery was required. The patients' stay in the ICU averaged 2.6 and 7.7 days respectively for one-stage and two-stage procedures, and the total stay in hospital averaged 14 and 33 days respectively. CONCLUSIONS: When possible, the one-stage procedure for anterior and posterior spinal fusion is preferred over the two-stage procedure because of a significant reduction in the length of stay in the ICU and in hospital, as well as reduced morbidity. However, this analysis should be interpreted cautiously because of the small number of cases and the variables encountered in treating this type of spinal deformity.

Adolescent↗
PubMed1992

Lumbosacral fusion in a patient with recurring Guillain-Barré syndrome and acute brachial neuritis.

A lumbar decompression and fusion with instrumentation was successfully completed on a patient with a history of acute brachial neuritis (ABN) and recurring Guillain Barré syndrome (GBS). Three weeks post-surgery there was a mild exacerbation of the GBS, which resolved with plasmapheresis. This case report shows that surgery may be conducted safely on a patient whose history includes GBS and ABN, without devastating neurological consequences.

Acute Disease↗
PubMed1992

Complications of forearm-plate removal.

Reconstruction of long-bone fractures with compression plates may give rise to stress shielding under the metal plate, which may be associated with late clinical problems due to insufficiency fractures around the implants. Therefore, it is common practice to remove forearm plates after fracture healing is completed. Increasing concern has been expressed recently about the complications and morbidity associated with forearm-implant removal. A retrospective review of the management of 111 forearm diaphyseal fractures at a major Canadian centre confirmed a substantial complication rate in elective forearm-plate removal. Because the true incidence of late insufficiency fracture is not well defined, elective forearm-plate removal may be contraindicated in the asymptomatic patient.

Bone Plates↗
PubMed1992

Experience with the "fixateur interne": initial clinical results.

Impressive clinical reports have come from several major spinal research centers regarding the results of using the AO spinal internal fixator, a recently released pedicle screw rod system. A retrospective review of the first 2 years of clinical results from a diverse group of orthopedic surgeons using this device at a Canadian University center may provide some insight into potential clinical outcomes in general use. These results contrast with the outcome data provided to date, which have been presented by expert academic spinal surgeons. The results suggest that there may be room for considering limited release of this device, perhaps with the requirement for special certification in its application.

Bone Screws↗
PubMed1991

Screw fixation of odontoid fractures and nonunions.

Surgical treatment of odontoid fractures has usually been carried out by C1-2 arthrodesis rather than by fracture fixation. An alternative treatment of compression screw fixation was used to treat selected acute odontoid fractures and nonunions. Ten patients were operated on. A variety of lag-screw types were used to compress and secure the fracture. Screw placement was considered excellent in five cases; in four, the screw tip protruded through the posterosuperior cortex of the dens by 1-3 mm. One patient died as a result of multiple injuries 2 days after surgery. In all other cases, including four cases of odontoid pseudarthroses, the fractures achieved solid union. It was concluded that screw fixation can be used for the successful treatment of selected odontoid fractures and nonunions.

Adult↗
PubMed1991

Post-traumatic compartment syndrome of the foot.

Post-traumatic compartment syndrome in the foot is an unusual but well-recognized entity. If there is an awareness of the condition at the time of presentation it can be diagnosed and treated effectively. A case of compartment syndrome in the foot of a 17-year-old boy after massive lower-extremity trauma is described. The simple and readily available diagnostic techniques are emphasized and an alternative approach to plantar decompression, which avoids exposure of and potential damage to the posterior tibial neurovascular bundle, is presented.

Adolescent↗
PubMed1991

Surgical palliation of spinal oncologic disease: a review and analysis of current approaches.

The clinical problem of primary and secondary vertebral tumours is encountered with increasing frequency throughout North America as oncologic management protocols evolve and the population continues to age. These lesions can present problems of pain, instability and paralysis. Optimal surgical palliation is often of benefit when more conservative methods have been unsuccessful. Vertebral tumours can be approached either anteriorly or posteriorly. These alternatives have led to the evolution in the clinical community of two "camps" championing their respective approaches. The authors have reviewed the accumulated literature up to December 1988 and have found that anterior approaches offer improved clinical outcome without substantially increased morbidity.

Humans↗