Predictors of Unilateral Spinal Block Success (UNISS)
Determination of Factors Affecting Success in Unilateral Spinal Anesthesia: A Prospective Observational Study
This prospective observational study aims to determine the factors affecting the success of unilateral spinal anesthesia in patients undergoing orthopedic lower extremity surgery. Unilateral spinal anesthesia is preferred to minimize unwanted effects such as hypotension and to provide more stable hemodynamic conditions, especially in vulnerable patient populations.
Unilateral spinal anesthesia is defined as achieving sensory and motor block predominantly on the operated side without significant contralateral spread. However, the factors influencing the success of this technique have not been fully clarified.
This study will evaluate various patient-related and procedure-related factors, including age, sex, body mass index, patient positioning, needle type and orientation, injection technique and local anesthetic dose. The primary outcome is the success of unilateral spinal anesthesia, defined as the absence of contralateral block.
The results of this study are expected to contribute to improving clinical practice by identifying major and minor factors affecting block success and optimizing anesthesia techniques.
Descripción general del estudio
Estado
Descripción detallada
This prospective observational study is designed to investigate the factors influencing the success of unilateral spinal anesthesia in patients undergoing lower extremity orthopedic surgery.
Spinal anesthesia is widely used in lower extremity procedures; however, it may be associated with hemodynamic instability such as hypotension. Unilateral spinal anesthesia has been proposed as a technique to limit sympathetic blockade and maintain more stable hemodynamic conditions. Despite its advantages, the determinants of successful unilateral block remain unclear.
Patients aged between 18 and 65 years with American Society of Anesthesiologists (ASA) physical status I-III who are scheduled for elective lower extremity surgery will be included in the study after providing written informed consent. This study will be conducted in a single tertiary care center.
No intervention will be performed by the investigator. All anesthesia procedures will be carried out according to routine clinical practice. The investigator will record patient demographics, including age, sex, height, weight, and body mass index.
Procedure-related variables such as patient positioning, spinal needle type, needle orientation, injection speed, level of injection, local anesthetic type and dose will be recorded.
Block characteristics will be assessed intraoperatively, including sensory and motor block distribution. The primary outcome is defined as successful unilateral spinal anesthesia, characterized by the absence of contralateral sensory block. Secondary outcomes include factors associated with block success and variability in block characteristics.
Data will be collected using standardized case report forms and analyzed to identify factors influencing the success of unilateral spinal anesthesia. The results of this study are expected to contribute to optimizing anesthesia techniques and improving patient safety.
Tipo de estudio
Inscripción (Actual)
Contactos y Ubicaciones
Ubicaciones de estudio
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Izmir, Turquía (Türkiye)
- İzmir City Hospital
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Criterios de participación
Criterio de elegibilidad
Edades elegibles para estudiar
- Adulto
- Adulto Mayor
Acepta Voluntarios Saludables
Método de muestreo
Población de estudio
Descripción
Inclusion Criteria:
- Patients aged 18-65 years
- ASA physical status I-III
- Undergoing elective unilateral lower extremity surgery under spinal anesthesia
- Provided written informed consent
Exclusion Criteria:
- ASA IV patients
- Known allergy to local anesthetics
- Contraindications to spinal anesthesia
- Decompensated congestive heart failure
- Hemodynamic instability (including sepsis, septic shock, or need for inotropic support)
- Pregnancy
- Patients with vertebral anomalies (e.g., scoliosis, vertebral fractures) preventing proper positioning
Plan de estudios
¿Cómo está diseñado el estudio?
Detalles de diseño
Cohortes e Intervenciones
Grupo / Cohorte |
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patients undergoing unilateral spinal anesthesia
Patients aged 18-65 years with ASA physical status I-III undergoing elective unilateral lower extremity surgery under spinal anesthesia.
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¿Qué mide el estudio?
Medidas de resultado primarias
Medida de resultado |
Medida Descripción |
Periodo de tiempo |
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Unilateral Spinal Block Success Rate
Periodo de tiempo: Intraoperative period (within first 30 minutes after spinal anesthesia
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Successful unilateral spinal anesthesia defined as the absence of contralateral sensory block, assessed by pinprick test and bromage scale within the first 20 minutes after spinal anesthesia.
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Intraoperative period (within first 30 minutes after spinal anesthesia
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Medidas de resultado secundarias
Medida de resultado |
Medida Descripción |
Periodo de tiempo |
|---|---|---|
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Rate of unilateral spinal anesthesia success by age
Periodo de tiempo: Intraoperative period
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Proportion (%) of patients achieving unilateral spinal anesthesia success across age groups.
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Intraoperative period
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Rate of unilateral spinal anesthesia success by BMI
Periodo de tiempo: Intraoperative period
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Proportion (%) of patients achieving unilateral spinal anesthesia success across age groups.
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Intraoperative period
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Rate of unilateral spinal anesthesia success by position
Periodo de tiempo: Intraoperative period
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Proportion (%) of unilateral spinal anesthesia success by patient positioning during injection (lateral vs sitting).
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Intraoperative period
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Rate of unilateral spinal anesthesia success by needle type
Periodo de tiempo: Intraoperative period
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Proportion (%) of unilateral spinal anesthesia success by spinal needle type (Quincke vs pencil-point).
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Intraoperative period
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Rate of unilateral spinal anesthesia success by needle gauge
Periodo de tiempo: Intraoperative period
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Proportion (%) of unilateral spinal anesthesia success by needle gauge.
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Intraoperative period
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Rate of unilateral spinal anesthesia success by local aneshtetic dose
Periodo de tiempo: Intraoperative period
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Proportion (%) of unilateral spinal anesthesia success by administered local anesthetic dose (mg).
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Intraoperative period
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Rate of unilateral spinal anesthesia success by injection speed
Periodo de tiempo: Intraoperative period
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Proportion (%) of unilateral spinal anesthesia success by injection speed category (faster vs ≤1 mL/5 s).
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Intraoperative period
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Sensory Block Level and Distribution
Periodo de tiempo: Intraoperative period
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Assessment of sensory block level (dermatomal level) and comparison between operated and non-operated sides.
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Intraoperative period
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Rate of unilateral spinal anesthesia success by intervertebral level of spinal injection
Periodo de tiempo: Intraoperative period
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Proportion (%) of unilateral spinal anesthesia success by intervertebral level (L1-2,L2-3,L3-L4 ,L4-L5).
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Intraoperative period
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Colaboradores e Investigadores
Patrocinador
Investigadores
- Investigador principal: Derya Arslan Yurtlu, MD, İzmir City Hospital
Fechas de registro del estudio
Fechas importantes del estudio
Inicio del estudio (Actual)
Finalización primaria (Actual)
Finalización del estudio (Actual)
Fechas de registro del estudio
Enviado por primera vez
Primero enviado que cumplió con los criterios de control de calidad
Publicado por primera vez (Actual)
Actualizaciones de registros de estudio
Última actualización publicada (Actual)
Última actualización enviada que cumplió con los criterios de control de calidad
Última verificación
Más información
Términos relacionados con este estudio
Palabras clave
Otros números de identificación del estudio
- UNISS-2025
Plan de datos de participantes individuales (IPD)
¿Planea compartir datos de participantes individuales (IPD)?
Descripción del plan IPD
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