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†.

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.