Paraplegia after surgery of the thoraco-abdominal aorta has been well reported. However, it is rare after pulmonary, tracheal or pleural surgery,2,3
with the overall incidence estimated to be 0.08%.1
Only five cases of paraplegia have been reported between 1966 and 2001 after oesophageal resection.2
The five cases previously described were performed on men in the 58–85 year age range who had advanced atherosclerotic disease and risk factors such as diabetes mellitus, hypertension and obesity. The resected tumours in these cases were located in the mid to distal oesophagus, with the level of spinal cord injury being located between T6 and L1. This is the area commonly fed by the great radicular artery of Adamkiewicz. This case is unique as the level of injury was located higher up, between T2 and T6.
The spinal cord is supplied with blood by one anterior spinal artery and two posterior spinal arteries. As they descend down the spinal cord, they are fed by segmental arteries that arise from the aorta. There are more segmental arteries supplying the posterior spinal arteries than the anterior arteries. This accounts for anterior spinal artery syndrome being more frequently observed than the posterior spinal artery syndrome.
Most radicular arteries arise from the left extraspinal vessels. Very often, a single, large radicular artery is found. The radiculo-medullary artery (artery of Adamkiewicz) constitutes the largest and most important radicular artery. It enters the spinal canal in variable segments—T7 to T12 in 75%, T5 to T8 in 15%, and L1 to L4 in 10%—with it being on the right in 17% of cases.
There is variability in the number and size of the supplying arteries—that is, both longitudinal arteries and the anterior spinal artery. This results in significant variation in the diameter.
The variability in the blood supply makes it difficult to identify and spare the specific blood vessels as they arise from the aorta. This creates a risk that surgical trauma can result in spinal cord ischaemia. The pathophysiology of the ischaemic insult may not be very clear.
Mechanisms for interruption of the blood supply are numerous.4
These include the inadvertent ligation of the artery of Adamkiewicz, lateral flexion of the spine during surgery5,6
or attempts to control bleeding at the costovertebral angle by using oxidised cellulose or ligation of intercostals vessels.6,7
Stagnation of blood within the vessels supplying the spinal cord can also occur as a result of prolonged periods of hypotension. Physiological factors can add to the risk including atherosclerosis, polycythaemia, and anatomic changes of the spine (kyphoscoliosis), vascular malformations and the hypercoagulability associated with malignancy. An epidural haematoma can also cause extrinsic compression, though paraplegia has been reported following thoracotomy in patients not receiving a thoracic epidural.5
Paraplegia resulting from inadequate blood supply through the anterior spinal artery produces a clinical picture known as anterior spinal artery syndrome. This is characterised by loss of motor function with intact or, more commonly, impaired sensory function below the level of injury.
In our case, while on one lung ventilation there was no significant observed fall in the saturations, with the patient maintaining saturations of 100% throughout. In addition the operation was uneventful with no documented hypotensive episode. The patient recovered in an intensive care unit and required no inotropic support as he was maintaining a mean arterial pressure >80 mmHg. In this patient an epidural haematoma or abscess was among the differential diagnoses as a cause for the paraplegia; however, this was excluded by means of an MRI scan. The cause of this patient’s injury is not clear because the lesion appears to be very high for an injury to the artery of Adamkiewicz, and there was no reported ligation of intercostal or spinal arteries and no intraoperative use of oxidised cellulose to attain haemostasis. Embolisation from an atherosclerotic plaque is the likely cause as the nature of the surgery required aortic and potentially left atrial manipulation.
In conclusion, spinal cord lesions rarely occur after oesophageal resection and are thought to be due to an ischaemic insult. It is therefore important to identify preoperatively patients who are at increased risk of compromised blood flow to the spinal cord, such as elderly patients with known risk factors for atherosclerosis, to implement preventive measures that may help avoid this complication. These measures may include preoperative echocardiography, reduced aortic manipulation and thromboprophylaxis both pre- and postoperatively. However, the avoidance of hypoxia and hypotension at any stage of the procedure must be paramount.
- Paraplegia following oesophageal resection is rare.
- The variability in blood supply to the spine makes it difficult to identify and spare the specific blood vessels as they arise from the aorta.
- Paraplegia resulting from inadequate blood supply through the anterior spinal artery produces a clinical picture known as anterior spinal artery syndrome.
- It is important to preoperatively identify patients who are at an increased risk.
- Preoperative optimisation of the patient with multidisciplinary input and required investigations is important to prevent patient morbidity and mortality.