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.
Panoramica dello studio
Stato
Descrizione dettagliata
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 di studio
Iscrizione (Effettivo)
Contatti e Sedi
Luoghi di studio
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Izmir, Turchia (Türkiye)
- İzmir City Hospital
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Criteri di partecipazione
Criteri di ammissibilità
Età idonea allo studio
- Adulto
- Adulto più anziano
Accetta volontari sani
Metodo di campionamento
Popolazione di studio
Descrizione
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
Piano di studio
Come è strutturato lo studio?
Dettagli di progettazione
Coorti e interventi
Gruppo / Coorte |
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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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Cosa sta misurando lo studio?
Misure di risultato primarie
Misura del risultato |
Misura Descrizione |
Lasso di tempo |
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Unilateral Spinal Block Success Rate
Lasso di tempo: 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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Misure di risultato secondarie
Misura del risultato |
Misura Descrizione |
Lasso di tempo |
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Rate of unilateral spinal anesthesia success by age
Lasso di tempo: 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
Lasso di tempo: 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
Lasso di tempo: 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
Lasso di tempo: 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
Lasso di tempo: 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
Lasso di tempo: 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
Lasso di tempo: 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
Lasso di tempo: 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
Lasso di tempo: 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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Collaboratori e investigatori
Sponsor
Investigatori
- Investigatore principale: Derya Arslan Yurtlu, MD, İzmir City Hospital
Studiare le date dei record
Studia le date principali
Inizio studio (Effettivo)
Completamento primario (Effettivo)
Completamento dello studio (Effettivo)
Date di iscrizione allo studio
Primo inviato
Primo inviato che soddisfa i criteri di controllo qualità
Primo Inserito (Effettivo)
Aggiornamenti dei record di studio
Ultimo aggiornamento pubblicato (Effettivo)
Ultimo aggiornamento inviato che soddisfa i criteri QC
Ultimo verificato
Maggiori informazioni
Termini relativi a questo studio
Parole chiave
Altri numeri di identificazione dello studio
- UNISS-2025
Piano per i dati dei singoli partecipanti (IPD)
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Descrizione del piano IPD
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