Table 2.

List of factors (independent variables) investigated

Patient-related risk factors

Age (years)

Sex

Body mass index (BMI) [kg/m²]

History of cardiac disease

History of hypertension

History of diabetes mellitus

History of respiratory disease

History of renal disease

Drug use

Antiplatelet (acetylsalicylic acid, clopidogrel)

Anticoagulant (acenocoumarol)

Preoperative scores

Revised cardiac risk index (RCRI)

Severe postoperative pain score

American Society of Anaesthesiologists (ASA) score

Surgery-related risk factors

Surgical technique (uni- or bilateral)

Iterative surgery at the same site

Number of operated levels (No.)

Associated foraminotomy

Surgical resection of an intracanalar synovial cyst

Surgical complications

Dural tear

Compressive epidural haematoma

Wound sepsis

Neurological damage