Editorial: Occipitocervical fixation

Abstract

For several reasons, occipitocervical fixation is a challenging surgical exercise. The procedure is performed infrequently, and the risks can be substantial. Vertebral artery injury can be catastrophic, bleeding during dissection can be a nuisance, and screw placement is often difficult. Surgery is even more complicated when the normal anatomy is obscured, or even missing. When this situation arises, novel techniques that have been well thought out can be a lifesaver for the practicing surgeon. The authors of “Occipital condyle to cervical spine fixation in the pediatric population” have provided a useful solution to one such problem: How does the surgeon fixate to the skull if the anatomy is compromised, or not there?3 The authors looked to the cadaver lab and previous clinical experience for a solution. The problem consisted of finding a location in the skull to place bilateral screws when the suboccipital area was anomalous or had been previously removed, such as in the case of a previously resected tumor or Chiari malformation surgery. The occipital condyle as a fixation point had been described in the adult,2,4–6 and in a single pediatric patient.1 Before performing this procedure in the operating room, the authors noted that the condyle had been shown to be a feasible fixation point in a previous cadaveric study.2,4 They then performed the procedure, with good success, in 4 pediatric patients who either had previous surgery or craniovertebral junction anomalies. There were no intraoperative or postoperative complications, and all 4 patients attained fusion. There are several other issues regarding this technique that deserve further emphasis. The use of intraoperative navigation cannot be overemphasized. Under the best of circumstances, cannulation of C-1 and/or C-2 is technically arduous. The task is even more challenging when the anatomy is abnormal, and downright daunting with the addition of the occipital condyle as a locus of fixation. Neuronavigation, such as with the O-arm or BrainLab, provides a measure of confidence and a margin for error during surgery. Feedback regarding screw placement can be obtained in real time, and screw trajectory can be altered before problems arise. Screw location and length can be assessed before the patient leaves the operating room. It is hard to imagine performing this procedure without this tool. The authors used recombinant human bone morphogenetic protein (rhBMP) to aid fusion, and justify its use by noting that 1 of the patients had previously undergone radiation treatment, and in a second patient, no decompression was necessary, and thus no local bone was available. While complication rates from iliac crest or rib harvest can be high, there are other options beside this type of autograft that are available to the surgeon. It should also be noted that there is a high rate of fusion in the pediatric population, particularly in the cervical spine. Given the current controversy surrounding the use of rhBMP, and the unknown long-term effects in children, all other options for attaining fusion should be considered in this patient cohort. Despite these concerns, this study extends our knowledge regarding the use of the occipital condyle as a site for screw placement. The authors have successfully translated a cadaveric and clinical finding to use in a specific patient population, and in the process have provided the pediatric spine surgeon another useful tool with which to successfully achieve occipitocervical fixation. (http://thejns.org/doi/abs/10.3171/2013.8.PEDS13368)