Impact of preservation of the latissimus dorsi muscle through a left anteroaxillary thoracotomy on spinal cord protection in descending thoracic and thoraco-abdominal aortic operations†

Abstract

OBJECTIVES The presence of collateral network circulation to the spinal cord, which is reflected in the repair of a descending thoracic aortic aneurysm (dAo) and a thoraco-abdominal aortic aneurysm (TAAo), has been demonstrated in clinical and animal experimental data. The latissimus dorsi muscle (LDM) including the thoracodorsal artery might be one of the major sources of this collateral network. The objective of this study was to evaluate the impact on spinal cord safety of a left anteroaxillary thoracotomy with minimal muscle division including preservation of the LDM in surgery for dAo and TAAo. METHODS Sixty-nine patients [64 (23–85) years old; 56 men] who underwent surgical repair for dAo and TAAo were divided into 2 groups: 29 [65 (23–84) years old] with an anteroaxillary thoracotomy with LDM preservation (PL group) and 40 [61 (28–85) years old] with a lateral thoracotomy without LDM preservation (NL group). RESULTS Aortic repairs were performed at the dAo in 30 patients including 14 in the PL group vs 16 in the NL group and at the TAAo in 39 patients including 15 in the PL group vs 24 in the NL group. There were 2 (2.9%) 30-day deaths; 2 (7.9%) in the PL group vs none in the NL group (P = 0.173). No strokes occurred. In patients with a femoro-femoral partial cardiopulmonary bypass with mild hypothermia, the incidence of loss of signal of motor-evoked potentials (>50%) was significantly lower in the PL group; 5.6% vs 31.8% (P = 0.039). The frequency of signal reduction of the remaining motor-evoked potential after surgery was also significantly lower in the PL group: 3.7% vs 25% (P = 0.040). Subsequently, the rate of spinal cord complications were lower in the PL group: 3.4% vs 12.5% (P = 0.188). CONCLUSIONS The left anteroaxillary thoracotomy with minimal incision of the muscles including the LDM might have potential advantages for spinal cord protection via preserved intramuscular collateral circulations to the spinal cord in dAo/TAAo open repairs.

Impact of preoperative identification of the artery of Adamkiewicz on spinal cord injury after descending aortic and thoracoabdominal aortic repair

“…Since more than 80% of patients with dTA/TAA aneurysms in a recent study had collateral blood pathways to the AKA around the spinal column, collateral blood pathways within the PLTMs may be important collateral blood pathways to the AKA and spinal code. Therefore, at the beginning of 2015, the current MSA through a left antero-axillary incision was adopted to preserve the collateral network circulation to the spinal code in the PLTMs ( 8 ). Although dTA and TAA surgery remain challenging, despite technical improvements, we have achieved better results with preoperative identification of the AKA and its targeted reconstruction.…”

“…However, reconstruction and/or preservation of AKA was not performed if there was no intraoperative MEP reduction, and if the ICA had been reconstructed in a previous operation, or if the preoperative CT showed a feeding artery to the anterior spinal artery other than AKA. At the beginning of 2015, the current muscle-sparing approach (MSA) through a left antero-axillary incision was adopted to preserve the collateral network circulation to the spinal cord in the posterolateral thoracic muscles (PLTMs) ( 8 ). On the other hand, in cases where the distal landing zone was below T8, we identified AKAs preoperatively, and as much as possible, the landing zone was placed so that it did not extend into the AKA in EVR.…”