RESUMEN
OBJECTIVE: This study evaluates if side posture lumbar manipulation is associated with a refractory period of the audible "crack" and if so, to quantify this refractory period across subjects. METHODS: Three subjects were exposed to multiple "baseline" side posture manipulations until no further audible cracks were recorded. "Test-refractory period" manipulations were administered after a set time (ie, potential refractory period) at which point the number of audible cracks was recorded. The refractory period was declared when a minimum of 50% of the baseline audible "cracks" had recovered during the test manipulations. The study design included 2 clinicians who performed side posture lumbar manipulation on asymptomatic subjects ranging from 38 to 49 years of age. RESULTS: The refractory period was 40 minutes for subject A, 70 minutes for subject B, and 95 minutes for subject C. The average refractory period across subjects was 68.33 minutes. The audible "crack" recovery was maintained for the remaining test days once the refractory period had been met. CONCLUSIONS: The audible "crack" heard during side posture lumbar manipulation is believed to originate from the zygapophyseal joints. This is supported by the presence of a refractory period and by the number of audible "cracks" found per manipulation.
Asunto(s)
Vértebras Lumbares/fisiología , Manipulación Espinal/métodos , Articulación Cigapofisaria/fisiología , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Postura , Rango del Movimiento Articular , Sonido , Factores de TiempoRESUMEN
STUDY DESIGN: Sixty-four asymptomatic participants, ranging in age from 22 to 49 years, volunteered to act as patients for the study. Twenty-eight different clinicians performed thoracic and lumbar spinal manipulative procedures. The range of clinical experience was 1 to 43 years. OBJECTIVES: The purpose of this study is to first locate the joints that produce an audible sound in response to manipulation (cavitation) during spinal manipulative procedures so that the accuracy and specificity of manipulation can be assessed. SUMMARY OF BACKGROUND DATA: Clinicians utilizing spinal manipulative therapy (SMT) claim to be very specific and accurate with the delivery of their dynamic thrust. It has been suggested that the clinical success of SMT is dependent on the accurate delivery of that therapy to the target spinal joints. METHODS: Asymptomatic participants received SMT to either the thoracic or lumbar regions of their spine. Accelerometers were secured to the skin over the spinal column, and the relative time at which each accelerometer detected the vibration from the cavitation associated with the SMT was used to calculate the source of the vibration. The site of cavitation was then compared with the target location. RESULTS: For lumbar SMT, the average error from target of 124 cavitations in lumbar procedures was 5.29 cm (at least one vertebra away from target), with a range of 0 to 14 cm. Of these cavitations, 57 were deemed to be accurate and 67 were deemed to be inaccurate. The average error from target of 54 cavitations in the thoracic spine was 3.5 cm, with a range of 0 to 9.5 cm. Of these cavitations, 29 were deemed to be accurate and 25 were deemed to be inaccurate. In most cases, individual manipulative procedures were associated with multiple cavitations ranging from 2 to 6. CONCLUSIONS: In the lumbar spine, SMT was accurate about half the time. However, because most procedures were associated with multiple cavitations, in most cases, at least one cavitation emanated from the target joints. In the thoracic spine, SMT appears to be more accurate.
Asunto(s)
Aceleración , Vértebras Lumbares , Manipulación Quiropráctica , Manipulación Espinal , Sonido , Vértebras Torácicas , Articulación Cigapofisaria/fisiología , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Especificidad de Órganos , Palpación , Reproducibilidad de los Resultados , Estrés Mecánico , VibraciónRESUMEN
OBJECTIVE: To assess the friction at the thoracic skin-fascia interface to determine the potential reaction force vectors during thoracic manual therapy. DESIGN: A basic in vivo study of human subjects, documenting the frictional properties at the interface between the thoracic skin and underlying fascia. BACKGROUND: Chiropractors, and other spine manipulative therapists, during thoracic manipulation have been attempting to apply force vectors to spine tissues in specific directions in addition to those applied normal to the skin. For obliquely applied forces to be directly transmitted to the underlying vertebrae, either friction is required at the skin-fascia interface or the applied force must "hook" on a bony process. METHODS: Subjects were placed in the prone position with the thoracic skin exposed. The posterior thoracic region was loaded with normal forces, incrementally from 125.3 to 392.9 N. The interface between the load and the skin was either a plexiglass plate or modelled hands. A force was then applied to either apparatus in the cephalad direction. The applied forces and corresponding displacements were measured using a load cell and an optoelectronic camera system, respectively. Chiropractors then performed actual thoracic manipulation to determine if they could maintain their location of contacts (spinous process/transverse process) on the underlying vertebra. RESULTS: Each of the subjects exhibited negligible friction between the thoracic skin and underlying fascia for both the plexiglass and modelled hand contacts. Furthermore, in each case, the apparatus travelled a distance greater than that between two transverse or spinous processes without showing an abrupt change in the slope of the force-displacement curves. The hands of chiropractors performing thoracic manipulation travelled a similar distance during the dynamic thrust. CONCLUSIONS: The skin-fascia interface over the thoracic spine exhibits negligible friction. Therefore, the reaction force from a thoracic vertebra will be normal to the overlying skin. Furthermore, the data show that the ability to "hook" either a thoracic transverse or spinous process in the superior-inferior direction during a manipulative thrust may be greatly over-rated. RELEVANCE: During thoracic spinal manipulation, one cannot direct a force vector to a thoracic vertebra at a given angle by simply directing their thrust in that direction.