title: How High Are Radiation-related Risks in Minimally Invasive Transforaminal Lumbar Interbody Fusion Compared With Traditional Open Surgery?: A Meta-analysis and Dose Estimates of Ionizing Radiation.
abstract: METHODS
  Meta-analysis and dose estimation.
  
  
  OBJECTIVE
  The aim of this study was to estimate radiation dose during minimally invasive transforaminal lumbar interbody fusion (MiTLIF) compared with open transforaminal lumbar interbody fusion (OTLIF) and evaluate the risk of radiation-related disease.
  
  
  BACKGROUND
  MiTLIF was introduced to reduce soft tissue injury and shows favorable perioperative outcomes. However, the disadvantage of MiTLIF is that, compared with OTLIF, it involves high radiation exposure because MiTLIF usually depends on a fluoroscopic guide. The additional cancer risk due to medical radiation exposure during the MiTLIF procedure has not yet been assessed.
  
  
  METHODS
  We searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials in June 2014 for studies directly comparing MiTLIF and OTLIF. Patient demographics, fluoroscopy time, intraoperative bleeding, and hospitalization period were extracted. The effective dose was converted from fluoroscopy time using formulas from prior studies.
  
  
  RESULTS
  Eight cohort studies with a total of 619 patients were identified. Mean fluoroscopy time was 39.42 seconds [95% confidence interval (CI), 38.01-40.83] during OTLIF and 94.21 seconds (95% CI, 91.51-96.91) during MiTLIF according to the meta-analysis. The pooled data revealed that patients who underwent MiTLIF were exposed to 2.4-fold more radiation than those who underwent OTLIF. Patients who underwent OTLIF and MiTLIF were exposed to 0.66 mSv (95% CI, 0.64-0.69) and 1.58 mSv (95% CI, 1.54-1.63) during the surgery, respectively. The lifetime risk of cancer was theoretically increased by 36.4×10 and 87.0×10 after OTLIF and MiTLIF, respectively. The risk of detrimental hereditary disorders associated with OTLIF and MiTLIF is 1.32×10 and 3.16×10, respectively.
  
  
  CONCLUSIONS
  Patients who underwent MiTLIF were exposed to 2.4-fold more radiation than those who underwent OTLIF. Although the theoretical cancer risk associated with radiation exposure may be tolerable, stochastic effects should not be disregarded.
authors.affiliation: *Department of Neurosurgery, Pusan National University Yangsan Hospital†Department of Neurosurgery, Ilsan Paik Hospital, Inje University College of Medicine, Goyang‡Department of Nuclear Engineering, Kyung Hee University, Suwon, Republic of Korea.
authors.forename: Chang Hyeun
authors.initials: CH
authors.lastname: Kim
authors.forename: Chang-Hyun
authors.initials: CH
authors.lastname: Lee
authors.forename: Kwang Pyo
authors.initials: KP
authors.lastname: Kim
mesh_terms: D016063:Blood Loss, Surgical; D004307:Dose-Response Relationship, Radiation; D006760:Hospitalization; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery*; D019060:Minimally Invasive Surgical Procedures / Q000379:methods*; D019990:Perioperative Care; D017594:Publication Bias; D011839:Radiation, Ionizing; D012307:Risk Factors; D013123:Spinal Fusion / Q000379:methods*; D016896:Treatment Outcome