Anterior cervical corpectomy for cervical spondylotic myelopathy: Experience and surgical results in a series of 70 consecutive patients

Abstract

Recently the debate over the management of cervical spondylotic myelopathy (CSM) has regained interest; more specifically whether treatment should be operative versus non-operative, raising the question about the real effectiveness of surgery in influencing the natural history of this pathology and about the choice of the most appropriate approach (anterior vs. posterior). The authors report a retrospective review of 70 consecutive patients who underwent elective anterior cervical corpectomy and fusion with iliac crest autograft or titanium mesh and placement of an anterior cervical plate for the treatment of CSM. The patients underwent pre-and postoperative evaluation, including history, and physical and neurological examination. Patients were also evaluated pre-and postoperatively using a modified version of the Japanese Orthopedics Association Scale (mJOA), which provides a fine semi-quantitative graded evaluation of overall function. Upon discharge home, patients were followed for an average of 42 months (range, 12–63 months). Following an anterior cervical decompression of the spinal cord, 94.2% of patients improved their functional status and 5.8% were unchanged; the mean preoperative mJOA score of all patients was 12.2, the postoperative was 15.4 and the amelioration was also documented by neurophysiological studies which showed an increase in amplitude and decrease in latency of somatosensory evoked potentials and motor evoked potential in 47 patients (67%). Older age and longer duration of preoperative symptoms both were not associated with a lower postoperative mJOA score (p < 0.47, p < 0.29, respectively). Single versus multiple level decompression was not predictive of a lower postoperative mJOA score (p < 0.18). Preoperative spinal cord low signal intensity changes on T1-weighted MRI were related to a lower postoperative mJOA score (p < 0.05), whereas spinal cord high-signal intensity changes on T2-weighted MRI were related to a higher postoperative mJOA score (p < 0.01); finally a lower preoperative mJOA score was highly predictive of a lower postoperative mJOA score (p < 0.0005). Anterior cervical corpectomy and fusion for CSM appears to be an effective procedure with a more favorable neurological improvement when compared to posterior decompressive laminectomy, minimally invasive procedures or non-surgical treatment. It is also a safe procedure even in the elderly population, with low morbidity and the potential for permanent spinal cord decompression and excellent bone stability.

Introduction

The clinical syndrome of cervical spondylotic myelopathy (CSM) was first described in the early 1950s.¹

The surgical management of CSM via an anterior approach, introduced by Smith and Robinson and subsequently by Cloward, although still widely adopted, is not universally accepted as it is still controversial whether this is the best management choice. Indeed, some previous studies describing this technique, have reported postoperative improvement, whereas others have documented no clinical change and, in some studies, even deterioration. These last studies have raised concerns about the effectiveness of an anterior approach in influencing the natural history of this disease.[2], [3] It is our opinion, however, that some of these studies are not representative for the following reasons: small size of the population studied; clinical heterogeneity; variability of symptoms ranging from pure neck pain to severe radiculopathy with or without myelopathy; unclear preoperative neurological status and imprecise surgical indications.⁴ We feel that many variables negatively influenced the populations studied, therefore no accurate patient stratification can be made.[5], [6], [7]

Recently, debate over the management of CSM has regained interest; specifically, over operative versus non-operative treatment and about the choice of the most appropriate approach (anterior vs. posterior).[8], [9], [10], [11], [12], [13], [14] A thorough review of the current literature points to a number of factors affecting the postoperative outcome; these include:

• age

• duration of symptoms at presentation

• preoperative neurological status

• T1-weighted and T2-weighted MRI signal intensity changes within the cord indicating cord damage.[15], [16]

As any combination of these factors may be predictive of the postoperative outcome, documenting them preoperatively is crucial for surgical decision-making.

Our aim is to clarify the efficacy and safety of anterior cervical decompression in improving the functional status of patients with CSM and in influencing the natural history of the disease. To this purpose we reviewed the results obtained at the neurosurgery department of Livorno City Hospital (Italy) from October 1997 to June 2002. Outcome, fusion rates, procedure-related complications, instrumentation failure and prognostic factors are assessed, along with pathophysiology and management of CSM. Relevant literature is also reviewed.