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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_6032_Библиотеки_им_академика_М_И_Перельмана
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Figure 7
revision surgery for either malposition or bone-implant interface failure.
Other reported complications include spinal cord injury (1.0%) and dural tear
(1.9%).
Other commonly cited intraoperative complications include vascular
injury involving the vertebral or carotid arteries, tracheoesophageal injury,
recurrent laryngeal nerve injury, and injury to the cervical sympathetic nerves
with resultant Horner syndrome. The specific mechanisms of and
management strategies for these complications are beyond the scope of this
chapter; however, management of recurrent laryngeal nerve injury warrants
attention. It is not uncommon to encounter a patient who has undergone prior
cervical surgery, either for a previous spinal intervention or for a thyroid, a
throat, or a vascular disorder. In these patients, the possibility of previous
recurrent laryngeal nerve injury exists, and preoperative laryngoscopic
evaluation should be performed to determine the status of vocal cord
function. If evidence of dysfunction exists, the surgical approach must be
performed on the side of the deficit to avoid the risk of bilateral vocal cord
paralysis, despite the difficulties associated with revision surgery.
Preoperative lateral radiograph (A), sagittal magnetic
resonance image (B), and sagittal (C) and axial (D and E)
CT scans obtained from a patient with severe cervical spondylotic
myelopathy in the setting of ossification of the posterior longitudinal
ligament. Given the kyphotic alignment of the cervical spine, an
isolated posterior approach is not suitable. This patient underwent a
combined anterior-posterior procedure using a multilevel anterior
cervical diskectomy and fusion to restore cervical lordosis followed by
a posterior cervical decompression and fusion for indirect
decompression of the spinal cord. The postoperative lateral
radiograph (F) demonstrates a solid fusion with correction of
preoperative kyphosis.
Postoperative Complications
In contrast to intraoperative complications, the incidence of postoperative and
late adverse events in the surgical treatment of CSM is much better defined in
the literature. In a recent study,28 postoperative or late complications
occurred in 37.5% of patients. During the 3-year study period, the most
common complications were persistent dysphagia (13.5%) and postoperative
neuropathic pain (7.7%). Other complications included neurologic
deterioration (4.8%) and wound problems (3.9%).
Revision surgery rates in surgically treated CSM have recently been
reported at 3.3% across all approaches at follow-up greater than 4 years; the
revision surgery rate was 2.5% for anterior procedures, 7.9% for posterior
laminoplasty, and 12.5% for posterior laminectomy and fusion. In addition to
differences seen on the basis of approach, male sex, diabetes, and associated
comorbidities were significantly associated with a higher rate of revision
surgery.29 Increased age and diabetes were associated with an increased risk
for adverse events. Surgical risk factors identified as predictive of
perioperative complications included longer surgical time and performing a
two-stage anterior-posterior procedure, although these were considered
indicators of increased case complexity and therefore associated with many
confounding variables. The authors were unable to comment on the
differences between anterior and posterior approaches, with the exception of
noting more axial neck pain in laminoplasty versus ACDF.
30
Adjacent-Segment Disease
Perhaps the most discussed and debated late complication after surgery for
cervical degenerative disease is the development of adjacent-segment disease.
Adjacent-segment disease is defined as the development of radicular or
myelopathic symptoms as a result of degenerative changes adjacent to a
previously decompressed level. This differs from adjacent-segment
degeneration, which is simply radiographic change in the absence of new
symptoms.31 This differentiation is clinically important because the incidence
of radiographic degeneration has been reported as high as 92% at follow-up
greater than 5 years; however, in that study, only 6.1% of patients required
reoperation secondary to their disease.
32
In the classic natural history study, the rate of adjacent-segment disease
after ACDF was found to be relatively constant at 2.9% per year over the first
10 years following surgery (Figure 8); two-thirds of these patients ultimately
required revision surgery.31 A more recent retrospective review of 672
patients treated with ACDF demonstrated a revision rate of 7% for adjacentsegment disease at an average follow-up of 34 months;33 the index
procedures for these revisions included single-level fusion (43%), two-level
fusion (53%), and three-level fusion (2%). For patients who have undergone
initial revision surgery for adjacent-segment disease, the likelihood of a
second revision surgery is significantly higher than after the initial procedure
(27% versus 12.2%) and the time between second and third revision surgery
is significantly shorter than the time between the index procedure and the first
revision surgery (30 versus 47 months).
34
Prevention of adjacent-segment disease is another controversy,
particularly relative to ACDF versus cervical TDA and whether motion
preservation of TDA results in lower rates of adjacent-segment disease. A
meta-analysis of six prospective, randomized controlled trials found no
significant difference in rates of reoperation at 2.5 years for adjacent-segment
disease following ACDF (6.9%) compared with TDA (5.1%). The annual rate
of revision for adjacent-segment disease was 2.4% in ACDF and 1.1% in
TDA.
35
Pseudarthrosis
An absence of solid fusion at sites of decompression can predispose patients
to continued or worsening symptoms and the need for revision surgical
procedures. Revision can consist of a repeat of the index procedure with
revision instrumentation, use of a different graft material (such as autograft),
or augmentation by means of a different approach (the addition of
supplemental anterior or posterior fixation).
Although fusion rates in the cervical spine are historically good, the
incidence of pseudarthrosis is significant. A recent evaluation of revision
rates for ACDF demonstrated a 7% revision surgery rate for pseudarthrosis.
Of these, 18% of patients initially underwent one-level procedures, 80%
underwent two-level procedures, and 2% underwent three-level procedures.
33
Numerous technical and host factors may determine whether fusion will
ultimately occur in a patient following an ACDF, but modifiable risk factors
such as smoking are given the most attention in the literature. The effect of
Figure 8
smoking on single-level ACDF was recently published from a cohort of 573
patients.36 An overall fusion rate of 91.4% was observed, with a rate of
91.6% in nonsmokers and 91.0% in smokers, with no significant difference.
However, in multilevel procedures, smokers have a significantly lower rate of
fusion; 81% of nonsmokers achieved stable arthrodesis compared with only
62% of smokers. Further subanalysis demonstrated that this effect was not
present in a group of patients undergoing subtotal corpectomy and strut
grafting, with equivalent fusion rates between cohorts. This finding suggests
that in patients who are unable or unwilling to cease tobacco use, corpectomy
may be a superior surgical option when treating multilevel disease.
37
Graph of the Kaplan-Meier survival curve demonstrating the
percentage of patients without symptomatic adjacent level
changes after anterior cervical diskectomy. (Reproduced with
permission from Hilibrand AS, Carlson GD, Palumbo MA, Jones PK,
Bohlman HH: Radiculopathy and myelopathy at segments adjacent to
the site of a previous anterior cervical arthrodesis. J Bone Joint Surg
Am 1999;81[4]:519-528.)
Alignment and Balance
When considering an anterior versus posterior surgical approach, it is
important to include cervical sagittal balance in treatment decision making. In
particular, cervical kyphosis places the cervical spinal cord at risk by
increasing intramedullary pressure and decreasing cervical blood flow, which
amplifies the effects of other compressive pathologies and accelerates
neuronal loss.
38
The influence of postoperative cervical alignment on surgical outcomes is
not yet completely clear, perhaps secondary to the difficulty in determining
what portion of the treatment effect results from restoration of alignment
versus decompression. However, a study initially designed to investigate
outcome differences between lordotic and parallel interbody grafts in ACDF
found that, although graft morphology did not influence clinical outcome,
maintenance of or improvement in segmental sagittal alignment resulted in
significantly greater improvements in SF-36 physical component summary
and NDI scores.39 This finding highlights the importance of sagittal
alignment and balance in the surgical treatment of degenerative cervical
disease.
Anterior cervical procedures are best for the restoration of cervical
lordosis and reestablishment of cervical sagittal balance in patients with
preoperative kyphotic deformity. When posterior procedures are indicated, it
is imperative to avoid substantial postoperative kyphotic deformity. A recent
study that compared laminoplasty with laminectomy and fusion in the
treatment of ossification of the PLL found that, although patients in both
groups demonstrated a loss of lordosis over time, patients in the fusion group
demonstrated better preservation of lordosis. Patients who underwent fusion
also maintained cervical sagittal balance, which suggests that posterior
cervical fusion best helps to avoid significant problems in patients at risk for
postoperative sagittal malalignment.40 In contrast, a retrospective
radiographic review of a new laminoplasty technique among patients with
33-month follow-up demonstrated a 1.8° increase in lordosis, which suggests
that changes in technique may allow better preservation of cervical
alignment.
41
Predicting which patients with preserved cervical lordosis are at risk for
postoperative kyphosis can be difficult. One study investigated the
preoperative risk factors for kyphosis after laminoplasty in 174 patients and
determined that patients with significant sagittal imbalance (defined as a
cervical sagittal vertical axis of greater than 42 mm) and those older than 75
years were at greater risk for the development of kyphotic deformity despite
preserved preoperative lordosis.42 The overall rate of postoperative kyphosis
was 5.2%.
Cervical Nerve Root Palsy
Cervical nerve root palsy is another complication encountered in the surgical
treatment of the degenerative cervical spine. This complication is
encountered in both posteriorly and anteriorly based procedures. The most
widely accepted mechanism of injury is stretch placed on the anatomically
shorter C5 nerve root as the spinal cord moves following decompression;
however, foraminal stenosis, root ischemia, and reperfusion injury also can
play a role.43 Cervical nerve root palsy manifests as clinical weakness in the
deltoid muscles and occasionally the biceps brachii. The incidence of C5
palsy in CSM is 5.8% in ACDF,44 5.3% in laminoplasty,45 and as high as
10.6% in laminectomy and fusion. Neurologic involvement is unilateral in
92% of patients. Proposed surgical risk factors for C5 nerve palsy include a
wider laminectomy trough, increased posterior cord drift, wide asymmetric
anterior decompression, and stretch injury secondary to substantial
restoration of lordosis.
A 2014 study demonstrated that patients with a postoperative C5 palsy
had significantly wider C5 laminectomy troughs (17.9 versus 15.2 mm) than
their counterparts without C5 palsy, and they also had significantly more
posterior spinal cord drift at the C3 through C6 levels.46 These results were
recently challenged by a 2016 retrospective review that demonstrated no
difference between laminectomy widths at C5 when comparing cohorts with
and without palsy.
47
With anterior surgery, wide and asymmetric decompression, as well as
substantial restoration of cervical lordosis, has been shown to result in a
higher incidence of C5 nerve palsy. A 2013 retrospective review showed that
decompressions greater than 15 mm and those that have a substantial side-to-
side difference significantly increased the risk of patients for the development
of nerve palsy, resulting in the recommendation of smaller, more symmetric
decompressions in CSM.48 Another retrospective review examined
restoration of cervical lordosis as a risk factor for C5 palsy and showed that
the nerve palsy cohort had a significantly larger increase in lordosis. The
study authors hypothesized that this injury is likely a result of increased
tension on the cord coupled with iatrogenic foraminal stenosis.44 Potential
strategies for mitigating these problems include avoiding overdistraction and
overcorrection at the intervertebral space and performing a prophylactic
foraminotomy during decompression.
With respect to foraminal stenosis and C5 nerve palsy, a retrospective
study of laminoplasty patients identified a significantly smaller foraminal
diameter for those in the palsy group compared with those without palsy
(1.99 versus 2.76 mm).45 No conclusions were made regarding the role of
prophylactic foraminotomy based on these data alone; however, another
study investigated its effect by prospectively reviewing the results of patients
treated with laminoplasty and bilateral prophylactic C4/C5 foraminotomy.
49
Of 141 consecutive patients, the rate of C5 palsy was 1.4%, which was
significantly improved from the 6.4% rate of nerve palsy in a historical
control group without foraminotomies. These results suggest that foraminal
stenosis plays an important role in the pathology of postoperative C5 nerve
palsy and should be considered in surgical planning.
Despite the significant functional morbidity associated with this
neurologic deficit, most patients recover with observation and nonsurgical
treatment measures: 71% of severe cases (manual muscle strength, 2 or less)
and 96% of mild cases (manual muscle strength, 3 to 4) have demonstrated
functional recovery without the need for further intervention.
44
Postoperative Infection
Infection rates after spinal fusion surgery range from 2% to 13%,50 which is a
substantial problem for the patient and the treating surgeon. In the cervical
spine, significant differences in the risk of infection exist between
approaches; posterior procedures have a much higher incidence of infection.
In addition to standard measures to help control perioperative infection,
surgeons have investigated additional means to reduce the rate of
postoperative infection. Two specific interventions are the use of topical
vancomycin powder and surgical drains.
Vancomycin powder is a low-cost intervention that provides a high
concentration of local antibiotic with coverage of methicillin-resistant
Staphylococcus aureus when applied directly to the surgical wound bed.
There is evidence supporting its clinical efficacy in cervical spine surgery,
with a retrospective cohort study of patients undergoing posterior cervical
fusion demonstrating a significant decrease in surgical site infection (from
10.9% to 2.5%) with the addition of 1 g of vancomycin powder to the wound
bed.50 In another study, a retrospective review of infection rates reported a
reduction in wound infection rates from 1.83% to zero following the
implementation of a protocol utilizing suprafascial drains in obese patients
and routine application of 500 mg of vancomycin powder in all patients.
51
Summary
Cervical degenerative disease comprises a wide range of compressive
pathologies that can result in substantial patient morbidity and even mortality.
Surgical decompression is an effective treatment and indicated in cases of
neurologic impairment. Surgical strategy varies widely based on
pathoanatomy, and the choice of a specific approach and technique should be
determined based on the number of levels involved, predominant symptoms
(radiculopathy versus myelopathy), and sagittal alignment. Complications
include adjacent-segment disease, pseudarthrosis, neurologic injury,
postoperative deformity, and infection. Despite the complexity of this
problem and the numerous different treatment options, careful attention to
patient symptoms, specific pathology, and surgical strategy will result in an
optimal outcome for affected individuals.
Key Study Points
Cervical radiculopathy is often a self-limited process for which almost
three-fourths of patients can be treated nonsurgically.
CSM is a progressive neurologic disorder with substantial morbidity and
possible mortality if untreated. Surgical decompression effectively
preserves neurologic function and is indicated in most patients who are
able to undergo surgery.
For patients with cervical kyphosis, posteriorly based procedures
performed with and without fusion have inferior results compared with
anterior approaches. If the pathology necessitates a posterior approach in a
patient with kyphosis, a combined anterior-posterior procedure should be
considered.
Postoperative adjacent-segment disease commonly develops at a rate of
approximately 2.9% per year. Currently, no identifiable differences exist
between adjacent segment revision rates in ACDF versus TDA.
C5 nerve palsy can occur in 4% to 10% of patients undergoing surgical
intervention for CSM. Proposed prevention strategies include limited
laminectomy width, avoidance of aggressive restoration of cervical height
and lordosis, and prophylactic foraminotomy.
Annotated References
1. Nouri A, Tetreault L, Singh A, Karadimas SK, Fehlings MG: Degenerative cervical
myelopathy: Epidemiology, genetics, and pathogenesis. Spine (Phila Pa 1976)
2015;40(12):E675-E693.
This comprehensive review reports on the different manifestations of degenerative
cervical myelopathy including the epidemiology, pathoanatomy, and genetics of the
disease. Level of evidence: V.
2. Woods BI, Hilibrand AS: Cervical radiculopathy: Epidemiology, etiology, diagnosis,
and treatment. J Spinal Disord Tech 2015;28(5):E251-E259.
This comprehensive review of cervical radiculopathy includes epidemiology,
pathoanatomy, diagnostic workup, and treatment options. In this study, 75% to 90% of
patients experienced resolution of symptoms with nonsurgical treatments including
immobilization, anti-inflammatory medications, physical therapy, and epidural steroid
injections.
3. Wong JJ, Côté P, Quesnele JJ, Stern PJ, Mior SA: The course and prognostic factors of
symptomatic cervical disc herniation with radiculopathy: A systematic review of the
literature. Spine J 2014;14(8):1781-1789.
This systematic review discusses the course and prognosis of cervical radiculopathy
secondary to cervical disk herniation. Symptomatic improvements were noted in 4 to 6
months; 83% of patients recovered in 24 to 36 months. Workers’ compensation patients
had a poorer prognosis for recovery.
4. Fehlings MG, Tetreault LA, Wilson JR, Skelly AC: Cervical spondylotic myelopathy:
Current state of the art and future directions. Spine (Phila Pa 1976)
2013;38(22suppl 1):S1-S8.
This narrative overview of 15 current publications on CSM summarizes the clinical
questions and evidence-based treatment recommendations. The importance of early
identification of CSM and the rapid establishment of an appropriate treatment course
was stressed.
5. Boden SD, McCowin PR, Davis DO, Dina TS, Mark AS, Wiesel S: Abnormal
magnetic-resonance scans of the cervical spine in asymptomatic subjects: A prospective
investigation. J Bone Joint Surg Am 1990;72(8):1178-1184.
6. Matsumoto M, Fujimura Y, Suzuki N, et al: MRI of cervical intervertebral discs in
asymptomatic subjects. J Bone Joint Surg Br 1998;80(1):19-24.
7. Nakashima H, Yukawa Y, Suda K, Yamagata M, Ueta T, Kato F: Abnormal findings on
magnetic resonance images of the cervical spines in 1211 asymptomatic subjects. Spine
(Phila Pa 1976) 2015;40(6):392-398.
This cross-sectional population study reported on cervical spine MRI findings in 1,211
subjects without clinical evidence of cervical disease; 87.6% demonstrated radiographic
findings of degenerative disease. All findings increased significantly with patient age.
Level of evidence: II.
8. Clarke E, Robinson PK: Cervical myelopathy: A complication of cervical spondylosis.
Brain 1956;79(3):483-510.
9. Boselie TF, Willems PC, van Mameren H, de Bie RA, Benzel EC, van Santbrink H:
Arthroplasty versus fusion in single-level cervical degenerative disc disease: A
Cochrane review. Spine (Phila Pa 1976) 2013;38(17):E1096-E1107.
This systematic review of nine randomized controlled trials compared TDA with fusion
in the treatment of degenerative cervical disorders. Significant differences existed in
favor of arthroplasty for arm pain, neck pain, and functional status; none were clinically
significant. Level of evidence: I.
total disc replacement versus anterior cervical discectomy and fusion for single-level
symptomatic cervical disc disease: Seven-year follow-up of the prospective randomized
U.S. Food and Drug Administration investigational device exemption study. J Bone
Joint Surg Am 2015;97(21):1738-1747.
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