RESUMEN
STUDY DESIGN: Cadaveric. OBJECTIVE: To determine the confidence with which surgeons should rely on a flexible ball-tipped probe to detect pedicle breeches in the thoracic and lumbar spine. SUMMARY OF BACKGROUND DATA: The reliability of a ball-tipped probe for detecting cortical violations of the pedicle tract has not been studied among fellowship-trained surgeons. METHODS: A total of 134 pedicles were randomized to have pedicle screw tracts with one of six possible options: no violation, anterior, superior, inferior, medial, or lateral violations. Five fellowship-trained spine surgeons examined each pedicle, using a standard flexible ball-tipped probe on three nonsequential occasions. The percentage of correctly identified violations, sensitivity, specificity, positive predictive value, and negative predictive value were calculated for the surgeons as a group and individually. The Cohen kappa coefficient was used to assess the accuracy of the observers and the interobserver and intraobserver agreement. Finally, we analyzed our results by spinal region to see whether this impacted the surgeons' ability to detect a pedicle violation. RESULTS: The surgeons were able to correctly identify 81% of intact pedicles, 39% of superior, 68% of medial, 74% of lateral, 62% of anterior, and 50% of inferior violations. The sensitivity varied considerably by breech location and surgeon with a range of 18% to 85%. Positive predictive value for each breech location ranged from 12% to 20%. The specificity was 81% and negative predictive value 98% overall. The intraobserver reliability was moderate and interobserver reliability was low in this series. The ability to detect a pedicle violation was significantly better in the lower thoracic region (T6-T12) than in other areas of the spine. CONCLUSION: The standard ball-tipped probe was much less reliable than expected. This technique can be used to confirm an intact pedicle but has an unacceptably high false-positive rate and should be used with caution. Our study suggests that overconfidence in pedicle probing might be dangerous.
Asunto(s)
Tornillos Óseos , Vértebras Lumbares/cirugía , Fusión Vertebral/instrumentación , Vértebras Torácicas/cirugía , Anciano , Anciano de 80 o más Años , Cadáver , Humanos , Monitoreo Intraoperatorio/métodos , Reproducibilidad de los Resultados , Fusión Vertebral/métodosAsunto(s)
Pie Equino/diagnóstico , Melorreostosis/diagnóstico , Neoplasias Óseas/diagnóstico , Niño , Enfermedad Crónica , Diagnóstico Diferencial , Pie Equino/etiología , Pie Equino/cirugía , Femenino , Pie/diagnóstico por imagen , Pie/patología , Hemangioma/diagnóstico , Humanos , Imagen por Resonancia Magnética , Melorreostosis/complicaciones , Melorreostosis/cirugía , Osteoma/diagnóstico , Osteomielitis/diagnóstico , Osteopoiquilosis/diagnóstico , Radiografía , Resultado del TratamientoRESUMEN
STUDY DESIGN: Parallel group design. OBJECTIVE: Compare the intraocular pressure responses in the prone flat versus prone Trendelenburg's position. SUMMARY OF BACKGROUND DATA: Postoperative vision loss (PVL) complicates approximately 0.05% of spine surgeries. Prone positioning is considered a risk factor because it increases intraocular pressure, which may decrease perfusion pressure to the optic nerve (perfusion pressure = mean arterial pressure - intraocular pressure [IOP]). The prone Trendelenburg's position is often used during spine surgery; however, its effect on optic nerve perfusion is unknown. The purpose of this study is to compare the IOP responses in the prone flat versus prone Trendelenburg's positions to determine if prone Trendelenburg's position also risks PVL. METHODS: Twenty subjects randomized into 2 groups. Group 1 lay in the prone flat position (0 degrees). Group 2 lay in the prone Trendelenburg's position (-7 degrees). IOPs were measured with a hand-held applanation tonometer while seated, 1 minute after assuming the group's position (Time 0), and at 10-minute intervals for 60 minutes. RESULTS: The differences in mean IOPs with respect to positions and time were significant (P = 0.0001, P = 0.000). There was a significant difference between sitting and all other times for both groups. In Group 1, there was a significant difference in IOP between Time 0 and all other times prone flat (P < 0.05). In Group 2, there was a significant difference in IOP between Time 0 all other times prone Trendelenburg (P < 0.05). CONCLUSION: IOP increases in the prone Trendelenburg's position, and when combined with other factors, may be a risk factor for PVL. The pathophysiology is discussed and suggestions for clinicians are made.
Asunto(s)
Inclinación de Cabeza/fisiología , Presión Intraocular/fisiología , Hipertensión Ocular/etiología , Complicaciones Posoperatorias/etiología , Posición Prona/fisiología , Trastornos de la Visión/etiología , Adulto , Femenino , Inclinación de Cabeza/efectos adversos , Humanos , Masculino , Hipertensión Ocular/fisiopatología , Complicaciones Posoperatorias/prevención & control , Distribución Aleatoria , Valores de Referencia , Riesgo , Tonometría Ocular , Trastornos de la Visión/prevención & controlRESUMEN
This study evaluated the improvement in range of motion after revision total knee arthroplasty (TKA) in a consecutive series of patients with TKAs presenting with pain and limited range of motion. Eleven stiff (range of motion <70 degrees ) and painful TKAs were revised with a posterior stabilized condylar prosthesis and reviewed after an average of 37.6 months (range, 24-53 months). The average range of motion increased from 39.7 degrees preoperatively to 83.2 degrees postoperatively. The mean flexion contracture decreased from 13.2 degrees to 0.9 degrees. Pain scores improved from 4.5 to 44.1, and all 11 patients were satisfied. This study shows that knee range of motion can improve significantly after revision TKA.