Background: Minimally invasive spine surgery is being popularized as a safe and effective alternative to open spine procedures. However, the negative results of this procedure are typically underreported in the literature because few spine surgeons submit and even fewer journals publish negative results. Methods: Using personal communications and second opinions with or without secondary surgery, the author reviewed negative results occurring within I year concerning 2 minimally invasive lumbar procedures: MED/METRx (Medtronic, Memphis, Tenn) and X-Stop (Kyphon Inc, St Francis Medical Technologies Inc, Alameda, Calif). Results: For, MED/METRx, 4 patients underwent MED/METRx procedures at outside institutions. Two patients reoperated upon by the author showed no evidence of scarring at the site of the lateral and far lateral disk herniations. The third patient (seen for second opinion only) exhibited progressive L4-5 discitis/osteomyelitis on successive MRI studies and was referred back to her original surgeon. The fourth patient (personal communication) underwent 2 MED/METRx procedures within 2 days for recurrent/residual disk herniation excision. An evolving cauda equina syndrome I month later required open surgery to repair a CSF fistula. For X-Stop, through personal communication, 2 elderly patients with severe comorbidities underwent 1- to 2-level X-StOp lumbar procedures resulting, in infection and hematoma, both of which required prolonged hospitalizations. Conclusions: The literature demonstrates few negative results/complications for minimally invasive spinal surgery. Encouraging more surgeons to submit and more journals to publish negative results for minimally invasive spinal approaches may better determine their safety/efficacy. (C) 2008 Elsevier Inc. All rights reserved.