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John S Kirkpatrick

Publications and source records attributed to John S Kirkpatrick.

7 recordsLinked to original sources
PubMed2006

The ability of MRI to predict failure of nonoperative treatment of pyogenic vertebral osteomyelitis.

Pyogenic vertebral osteomyelitis (PVO) can be treated most often by medical management. For those failing with medical management, surgical delay can result in increased morbidity. Therefore, the ability to predict failure of medical management on presentation would greatly improve the outcome. This study determines the ability of the presenting magnetic resonance imaging scan to predict failure of nonoperative management at the onset of treatment. A cohort of patients with PVO, initially treated medically, was reviewed. Imaging, demographics, and clinical data of patients successfully treated medically were compared with those ultimately requiring surgical treatment. The extent of signal change on the T1-weighted sagittal images of the affected motion segment was determined for each group. Twenty-two patients were included in the study. Patients successfully treated medically averaged 57%+/-19% of motion segment involvement, whereas those failing conservative treatment averaged 89%+/-18%. Using 90% involvement as an indication for initial surgery would have a sensitivity of 78% and specificity of 93%. Patients with thoracolumbar PVO who have 90% or higher involvement of an affected motion segment should be considered for early operative management.

Adult↗
PubMed2006

Short segment fixation of thoracolumbar burst fractures.

Short segment instrumentation for thoracolumbar fractures or fracture dislocations continues to be controversial. Recently, a load-sharing classification score was developed to help predict failure of posterior instrumented fusion alone used for highly comminuted and kyphotic fractures. Twenty-two patients treated with short-segment posterior instrumentation for thoracolumbar fractures were retrospectively reviewed. Although posterior instrumented fusion was used for fractures with a relatively high load sharing classification score, the load-sharing classification score was not predictive of posterior instrumentation failure. Single-level cephalad instrumentation failed at a higher rate than two-level cephalad instrumentation.

Adolescent↗
PubMed2005

Corrosion on spinal implants.

OBJECTIVE: Modular spine implants are used as an aid to obtaining fusion, but fretting and corrosion occur between modular components in a biologic environment. METHODS: Forty-eight spinal implant constructs manufactured by a variety of companies were retrieved from 47 patients and were subjected to surface analysis stereomicroscopy. RESULTS: Stainless-steel implants (n = 23) had either semirigid constructs with mild or no surface alteration (n = 7) or rigid constructs with moderate or severe alteration (n = 16). Surface damage was consistent with previously observed mechanically assisted crevice corrosion phenomena. Titanium alloy implants (n = 25) showed no significant corrosion but had three constructs with fatigue failure of anchoring screws. One cobalt alloy construct showed no evidence of corrosion. CONCLUSIONS: Long-term effects of fretting and corrosion are unclear, and minimization of these phenomena seems justified. Selection of modular components with similar materials and surface finish may help the surgeon minimize localized changes over time. Stainless-steel implants with rigid interconnections and those with different surface finishes between rods and connectors are most susceptible to corrosion.

Alloys↗
PubMed2004

Cervical spine injury and restraint system use in motor vehicle collisions.

CONTEXT: Cervical spine injury related to motor vehicle collision (MVC) is a severe and often permanently disabling injury. Although advances in automobile crashworthiness have reduced both fatalities and some severe injuries, the impact of varying occupant restraint systems (seatbelts and airbags) on cervical spine injury is unknown. OBJECTIVE: To investigate the relationship between the occurrence of cervical spine injury and occupant restraint systems among front seat occupants involved in frontal MVCs. DESIGN, SETTING, AND PATIENTS: A case-control study among subjects obtained from the 1995 to 2001 National Automotive Sampling System (NASS). Cases were identified based on having sustained a cervical spine injury score of 2 or more on the Abbreviated Injury Scale, 1990 Revision. RESULTS: Approximately half (44.7%) of 8,412 cases of cervical spine injury were unrestrained occupants while belted only, airbag only, and both restraint systems represented 38.2%, 8.8%, and 8.4% of cases, respectively. Overall, the combined use of airbag and seatbelt had the greatest protective effect, relative to unrestrained occupants, with an odds ratio (OR) of 0.19 and a 95% confidence interval (CI) of 0.12 to 0.30. Use of a seatbelt only also had a protective effect (OR: 0.40; 95% CI: 0.23-0.70). Occupant use of an airbag only neither increased nor decreased the risk of cervical spine injuries relative to unrestrained occupants (OR: 1.02; 95% CI: 0.57-2.13). CONCLUSIONS: The results of this study suggest that there is an increase in overall protection against cervical spine injury by combining airbag and seatbelt restraint systems relative to seatbelt alone.

Accidents, Traffic↗
PubMed2003

The acute effects of posterior fusion instrumentation on kinematics and intradiscal pressure of the human lumbar spine.

Nine cadaver lumbar spines were analyzed by applying nonconstraining nondestructive bending moments while measuring global range of motion, mechanical reaction at the sacrum, applied moment at the top of the specimen, segmental range of motion at L1-L5, and IDP at L1-L4. Each specimen was examined in an intact and instrumented state (with L3-L4 posterior instrumentation) using range of motion-based biomechanical testing, while achieving a similar global ROM in the sagittal, frontal, and transverse planes. An increase in applied moment was required during instrumented testing when compared with intact, and a significant increase in segmental range of motion during instrumented testing was found at all uninstrumented levels. Significant decreases in segmental range of motion were measured at the instrumented level when compared with intact testing. The most significant decreases and increases in IDP occurred at the instrumented level during sagittal and transverse plane testing.

Aged↗
PubMedDate not supplied

Thoracolumbar fracture management: anterior approach.

The surgeon who treats patients with spine trauma must be able to apply a variety of management techniques to achieve optimal care of the patient. The anterior surgical approach is appropriate for some thoracolumbar burst fractures in patients with neurologic deficit and without posterior ligamentous injury. Surgery is most often indicated for patients with incomplete deficit, especially those with a large retropulsed fragment, marked canal compromise, severe anterior comminution, or kyphosis <30 degrees. This approach provides excellent visualization of the anterior aspect of the dura mater for decompression. Reconstruction of the anterior body defect can be done with autograft, allograft, or a cage. Supplementation of the graft with anterior internal fixation helps prevent kyphosis. Clinical results demonstrate improved neurologic function in most patients as well as low pseudarthrosis rates. In patients with incomplete deficit, improvement in neurologic function usually can be expected with few complications.

Contraindications↗