The Effect of Transpedicular Intracorporal Grafting in the Treatment Thoracolumbar Burst Fractures on Canal Remodeling

Ahmet Alanay,
Emre Acaroglu,
Muharram Yazici,
Adil Surat Sihhiye,
Ankara, Turkey

PURPOSE:
Transpedicular intracorporal grafting in combination with short segment instrumentation has been offered as an alternative to prevent failure. The concern still exists about the potential complication of further canal narrowing or failure of remodeling with this technique. This study prospectively evaluated canal remodeling in patients treated with transpedicular intracorporal grafting.

PATIENTS AND METHODS:
Twenty–one patients with thoracolumbar burst fractures were randomized into transpedicular grafting (TPG) (n=11) and non–TPG (NTPG) (n=10) groups and were prospectively followed for an average of 50 months (25– 85). Groups were similar for age, type of fracture, load sharing classification and kyphotic deformity. Preoperative, postoperative and follow–up CT images through the level of pedicles were obtained, corrected for differences in magnification, and digitized. Areas of the spinal canals were measured and normalized by the estimated area at that level (average of adjacent levels).

RESULTS:
There were no operative complications in any of the groups. Average sagittal index was 19.7±6.2 degrees at presentation, was corrected to 1.9±4.9 degrees by operation, but was found to have been deteriorated to 9.1+–6.4 degrees at final follow–up. There were no differences between groups regarding the evolution of sagittal deformity. Spinal canal narrowing was 38.5±18.2 % at presentation, 22.1±19.8 % postop, and further improved to –2.5±16.7 % at follow–up, similar for both groups (Table 1).

Canal narrowing	TPG	NTPG	P value
Pre–operative	40.5±16.9%	36.1±20.4%	0.601
Post–operative	24.2±20.6%	19.6±20.0%	0.648
Correction	15.9±14.0%	18.5±14.3%	0.969
Follow–up	0.4±10.9%	–5.4±21.3%	0.476
Remodeling	27.8±20.3%	24.5±11.8%	0.109

DISCUSSION:
Our results demonstrate that transpedicular intracorporal grafting in the treatment of burst fractures does not effect the rate of reconstruction of the canal area as well as remodeling. Spinal canal remodeling was observed to occur in all patients regardless of grafting, eventually leading to overcorrection in some. On the other hand, it was also seen that this technique is not effective in preventing the deterioration of radiological findings in patients treated with short segment posterior instrumentation.