Cervical spondylotic myelopathy: the outcome and potential complications of surgical treatment

Cervical spondylotic myelopathy is the most common cause of spinal cord dysfunction in patients over 60 years old. Symptoms often develop gradually and insidiously and are characterized by neck stiffness, arm pain, numbness and clumsiness of hands, as well as weakness of the hands and legs frequently leading to a change in mobility. Surgery is performed primarily to prevent the progression of symptoms but also with the aim of improving existing symptoms. Aim of our study was to assess the outcomes and potential complications of surgical decompression of cervical spondylotic myelopathy (CSM).

Prospective data was collected from 71 patients who were treated surgically for CSM over a four-year period (June 2006 to June 2010). Only patients with confirmed spondylotic cervical myelopathy were included in the study; those with an inflammatory, infectious or neoplastic etiology were excluded. The Nurick scale was used as a primary outcome measure, and the improvement in upper limb function as a secondary outcome measure. Statistical significance was assessed using the paired t-test.

34/71 (47.9%) patients had an anterior decompression, 36/71 (50.7%) patients underwent posterior surgery and one patient (1.4%) received a combined approach: The Nurick score: The mean score improved by 0.9 from 2.4 preoperatively to 1.5 postoperatively for the whole series. Three patients were able to return to work. The preoperative Nurick score showed a positive correlation with the postoperative Nurick score at one year (Pearson Coefficient = 0.85). Upper limb symptoms: Postoperatively, 24 patients were free of any upper limb involvement compared with 6 patients preoperatively. The main improvement was in patients who prior to surgery had subjective symptoms with no objective signs of weakness or muscle wasting. 35/48 (72.9%) of this group showed improvement compared to 7/17 (41.2%) of patients who demonstrated objective weakness and/or wasting preoperatively.

The overall rate of complications was 18.2%. There were two mortalities as a result of pneumonia (2.8%), one patient had to be transferred to the intensive care unit for cardiac failure (1.4%), fixation failure occurred in two patients (2.8%), worsening of myelopathy occurred in two patients (2.8%), C5 temporary radiculopathy presented in two patients (2.8%), superficial wound infection developed in one patient (1.4%) and three patients (4.2%) complained of severe axial pain in the postoperative period. DISCUSSION Our results demonstrate that the greater the preoperative disability the greater the final disability is expected to be. Cord signal change, as an indicator of the pathological severity of the disease, correlates with a worse functional outcome. The degree of improvement postoperatively (i.e. the functional change) does not show a significant correlation with the initial preoperative status. It appears however, that there is a better chance of improvement in patients with no objectively detectable weakness or muscle wasting. The rate of complications encountered in this series is comparable with those in the literature, which renders them valid for quoting when considering surgical treatment for CSM.

Surgical decompression offers a real chance of improvement in the functional outcome of CSM, especially during the earlier stages of the disease. The surgical decision needs to be considered carefully due to the advanced age of the patient population and the greater burden of co-morbidities, which increase the surgical risks significantly.