Table 3.

Classification of major and minor complications*

Complication category	Major	Minor
Respiratory	Respiratory distress of any cause (significantly low oxygen saturation or prolonged intubation), pneumonia, significant atelectasis (requiring prolonged chest tube)	Asymptomatic pleural effusion, pneumothorax, atelectasis, or lung contusion
Neurologic	Convulsions, motor or sensory deficiencies, prolonged urinary retention	Temperature difference between legs
Hematologic	Continuous bleeding from incisions, venous thrombosis	Asymptomatic coagulopathy or thrombocytopenia
Gastrointestinal	Recurrent gastrointestinal bleeding	Constipation, elevated liver enzymes or bilirubin, nausea or vomiting
Cardiovascular	Hemodynamic instability (defined as systolic pressure < 90 mm Hg combined with clinical parameters of low peripheral perfusion)	Low blood pressure at arrival to the floor, temporary oliguria
Wound/Infection	Wound infection requiring return to the operating room	Wound resolved with local wound care, urinary tract infection
Instrumentation failure	Required reoperation	Asymptomatic
Curve progression	Required reoperation	Asymptomatic
Miscellaneous	Decubitus ulcer, fever > 39°C	Fever ≤ 39°C

* Modified from Hod-Feins et al. [7].