Page 706 - Motor Disorders Third Edition

688 / chapter 42
which predisposes to draping of the cord over the ante-
rior spinal elements. Anterior corpectomy accompanied
by intervertebral fusion with an allograft, harvesting iliac
crest or fibular strut, are effective anterior approach that
achieves the goals of decompression via anterior osteophyte
removal and stabilization of excessively mobile segments
by interbody graft fusion. The factors predictive of a favor-
able prognosis in CSM with surgical intervention via ante-
rior decompression and fusion have included age younger
than 60 years and duration of symptoms less than two years
(41). The most widely cited disadvantages of the anterior
approach are increased operative time, complexity, and a
higher incidence of operative complications (42, 43). In
addition, technical and biomechanical considerations may
preclude anterior decompression of disease that extends
beyond three spinal segments. Complications are typically
related to injury of the various vascular, neural, and vis-
ceral structures in the anterior neck. One common one is
C-5 radiculitis; others include hoarseness due to recurrent
laryngeal nerve injury, dysphagia, wound infection, and
hematoma, in addition to worsening of the myelopathy.
Complications related to fusion include bleeding and infec-
tion at the graft donor site and graft extrusion that occur in
3 to 10% of patients.
RECOMMENDATIONS
An analysis of the results reported for anterior and poste-
rior decompressive approaches to CSM provides no clear
consensus as to which approach offers optimal results.
However, among 84 patients treated with anterior corpec-
tomy or posterior laminectomy and followed a mean of 7.35
years (44), initial improvement was seen in about 70% of
patients operated by either approach. Long-term follow-up
revealed sustained improvement in 54% of anterior oper-
REFERENCES
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ated cases and 37% of posterior approaches. At follow-up,
18% of anterior patients and 37% of posterior patients had
deteriorated. Posterior approaches were not combined with
fusion in this series, and the issue of postoperative instabil-
ity was not addressed. The risk of late decline strongly cor-
related with duration of preoperative symptoms, suggesting
that some patients with CSM have sustained irreversible
cord damage before surgery, a supposition supported by
pathologic cord studies. The vascular pathology associ-
ated with CSM may be a contributing factor in late dete-
rioration. When evaluating approaches to CSM, a complete
evaluation of potential morbidity and mortality should be
undertaken. The incidence of reported complications from
anterior approaches is extremely variable ranging from 3 to
48%. Complications are somewhat less frequent in posterior
decompressive surgery, but the incidence of postoperative
deformity is as high as 42%. Mortality for both approaches
is 2% or less.
The proposed management of CSM should be guided
by a consideration of the risks and benefits of conservative
management, followed by a discussion of the indications,
advantages, and limitations of a given intended surgical
approach (45), incorporating the insights of evidence-based
studies (37). The favored surgical approach or approaches
will be those that allow removal of the compressive elements
most directly, taking into consideration the curvature of the
cervical spine, whether lordotic or kyphotic, and the loca-
tion and extent of compression. For segmental disease over
one to three spinal levels, anterior discectomy or corpec-
tomy with interbody fusion (ACDF or ACCF) should be
considered. For posteriorly located compressive elements
or diffuse disease that extends over more than three levels,
a posterior approach is generally preferred. Additionally,
posterior fusion and instrumentation may be required to
avoid postoperative instability.
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