Letter to the Editor: Transpedicle Body Augmenter: A Further Step in Treating Burst Fractures

Dear Sir, We read with interest the article ‘‘Transpedicle Body Augmenter A Further Step in Treating Burst Fractures’’ by Li et al. [5]. This article addressed short-segment fixation well by comparing patients treated with a transpedicle body augmenter with a control group of patients treated with short-segment posterior instrumentation. The issue of short-segment versus long-segment fixation is a matter of debate among spine surgeons. Where shortsegment fixation allows preservation of more mobile segments of the spine, it compromises the strength of fixation construct [4, 6]. This led to a new dimension in management of vertebral fractures, that is, augmentation of shortsegment fixation. The methods used for augmentation of short-segment fixation include kyphoplasty [1], vertebroplasty [2], transpedicle bone grafting [3] and transpedicle body augmenter [5]. Except for transpedicle bone grafting, good results have been reported for all other forms of augmentation as compared with short-segment fixation alone. Short-segment pedicle screw fixation is reportedly associated with a 20% to 50% incidence of pedicle screw failure and progressive spinal deformity. The question today is whether the various techniques used for augmentation of short-segment pedicle screw fixation have results comparable to those of long-segment pedicle screw fixation, which we believe is a gold standard [8] for posterior spine stabilization as far as sagittal index and anterior body compression are concerned. We have some concerns regarding the study by Li et al. [5]. First, the postoperative protocol is important in any kind of spinal surgery, however, the authors provide no details of the protocol in this article. As delayed ambulation after short-segment fixation is known to give good results [7], postoperative protocol with specific mention of ambulation should be provided. Moon et al. [7] reported short-segment fixation without posterolateral fusion is an effective procedure for compression and burst fractures if postoperative mobilization is delayed by 2 to 4 weeks. It would be better if the results of the transpedicle body augmenter were compared with results of long-segment fixation. Second, Li et al. report mean times of surgery as 66.1 ± 12.1 minutes and 63.4 ± 16.6 minutes for the augmenter and control groups respectively. Does this mean no additional time is required for: (1) preparation of bilateral pedicle tunnels to the fractured vertebra by an awl followed by serial custom made trials (enlargers) to prepare for TpBA passage; (2) harvesting the bone graft from the iliac crest; (3) filling the vertebral body with autologous bone graft; (4) inserting the augmenter through the pedicle; and (5) filling the pedicle tunnel space with bone graft? Third, blood losses reported for the augmenter and control groups are 216 ± 65 cc and 240 ± 87 cc, respectively, which means the blood loss was less in the group in which two additional pedicle tunnels were made and bone (Re: Li KC, Hsieh CH, Lee CY, Chen TH. Transpedicle body augmenter: a further step in treating burst fractures. Clin Orthop Relat Res. 2005;436:119–125.)