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Predictors of Unilateral Spinal Block Success (UNISS)

6 mai 2026 mis à jour par: Derya Arslan Yurtlu, Izmir City Hospital

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.

Aperçu de l'étude

Statut

Complété

Les conditions

Description détaillée

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.

Type d'étude

Observationnel

Inscription (Réel)

318

Contacts et emplacements

Cette section fournit les coordonnées de ceux qui mènent l'étude et des informations sur le lieu où cette étude est menée.

Lieux d'étude

Critères de participation

Les chercheurs recherchent des personnes qui correspondent à une certaine description, appelée critères d'éligibilité. Certains exemples de ces critères sont l'état de santé général d'une personne ou des traitements antérieurs.

Critère d'éligibilité

Âges éligibles pour étudier

  • Adulte
  • Adulte plus âgé

Accepte les volontaires sains

Non

Méthode d'échantillonnage

Échantillon non probabiliste

Population étudiée

Adult patients aged 18-65 years with ASA physical status I-III undergoing elective unilateral lower extremity surgery under spinal anesthesia in a single tertiary care center.

La description

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 d'étude

Cette section fournit des détails sur le plan d'étude, y compris la façon dont l'étude est conçue et ce que l'étude mesure.

Comment l'étude est-elle conçue ?

Détails de conception

Cohortes et interventions

Groupe / Cohorte
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.

Que mesure l'étude ?

Principaux critères de jugement

Mesure des résultats
Description de la mesure
Délai
Unilateral Spinal Block Success Rate
Délai: Intraoperative period (within first 30 minutes after spinal anesthesia
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.
Intraoperative period (within first 30 minutes after spinal anesthesia

Mesures de résultats secondaires

Mesure des résultats
Description de la mesure
Délai
Rate of unilateral spinal anesthesia success by age
Délai: Intraoperative period
Proportion (%) of patients achieving unilateral spinal anesthesia success across age groups.
Intraoperative period
Rate of unilateral spinal anesthesia success by BMI
Délai: Intraoperative period
Proportion (%) of patients achieving unilateral spinal anesthesia success across age groups.
Intraoperative period
Rate of unilateral spinal anesthesia success by position
Délai: Intraoperative period
Proportion (%) of unilateral spinal anesthesia success by patient positioning during injection (lateral vs sitting).
Intraoperative period
Rate of unilateral spinal anesthesia success by needle type
Délai: Intraoperative period
Proportion (%) of unilateral spinal anesthesia success by spinal needle type (Quincke vs pencil-point).
Intraoperative period
Rate of unilateral spinal anesthesia success by needle gauge
Délai: Intraoperative period
Proportion (%) of unilateral spinal anesthesia success by needle gauge.
Intraoperative period
Rate of unilateral spinal anesthesia success by local aneshtetic dose
Délai: Intraoperative period
Proportion (%) of unilateral spinal anesthesia success by administered local anesthetic dose (mg).
Intraoperative period
Rate of unilateral spinal anesthesia success by injection speed
Délai: Intraoperative period
Proportion (%) of unilateral spinal anesthesia success by injection speed category (faster vs ≤1 mL/5 s).
Intraoperative period
Sensory Block Level and Distribution
Délai: Intraoperative period
Assessment of sensory block level (dermatomal level) and comparison between operated and non-operated sides.
Intraoperative period
Rate of unilateral spinal anesthesia success by intervertebral level of spinal injection
Délai: Intraoperative period
Proportion (%) of unilateral spinal anesthesia success by intervertebral level (L1-2,L2-3,L3-L4 ,L4-L5).
Intraoperative period

Collaborateurs et enquêteurs

C'est ici que vous trouverez les personnes et les organisations impliquées dans cette étude.

Parrainer

Izmir City Hospital

Les enquêteurs

  • Chercheur principal: Derya Arslan Yurtlu, MD, İzmir City Hospital

Dates d'enregistrement des études

Ces dates suivent la progression des dossiers d'étude et des soumissions de résultats sommaires à ClinicalTrials.gov. Les dossiers d'étude et les résultats rapportés sont examinés par la Bibliothèque nationale de médecine (NLM) pour s'assurer qu'ils répondent à des normes de contrôle de qualité spécifiques avant d'être publiés sur le site Web public.

Dates principales de l'étude

Début de l'étude (Réel)

10 août 2025

Achèvement primaire (Réel)

1 février 2026

Achèvement de l'étude (Réel)

1 février 2026

Dates d'inscription aux études

Première soumission

9 avril 2026

Première soumission répondant aux critères de contrôle qualité

6 mai 2026

Première publication (Réel)

12 mai 2026

Mises à jour des dossiers d'étude

Dernière mise à jour publiée (Réel)

12 mai 2026

Dernière mise à jour soumise répondant aux critères de contrôle qualité

6 mai 2026

Dernière vérification

1 mai 2026

Plus d'information

Termes liés à cette étude

Mots clés

Autres numéros d'identification d'étude

  • UNISS-2025

Plan pour les données individuelles des participants (IPD)

Prévoyez-vous de partager les données individuelles des participants (DPI) ?

NON

Description du régime IPD

Individual participant data will not be shared due to patient confidentiality and institutional data protection policies

Ces informations ont été extraites directement du site Web clinicaltrials.gov sans aucune modification. Si vous avez des demandes de modification, de suppression ou de mise à jour des détails de votre étude, veuillez contacter register@clinicaltrials.gov. Dès qu'un changement est mis en œuvre sur clinicaltrials.gov, il sera également mis à jour automatiquement sur notre site Web .

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