Key-words:
Cervical laminectomy - cervical spondylotic myelopathy - neurological recovery - surgical
outcome
Introduction
Cervical spondylotic myelopathy (CSM) is a progressive degenerative spine disease
and the most common cause of spinal cord dysfunction in adults worldwide.[[1]],[[2]],[[3]] The structural changes involved in CSM includes (1) degeneration of intervertebral
discs, vertebral bodies, and facet joints; (2) hypertrophy of the ligamentum flavum;
and (3) ossification of posterior longitudinal ligament (OPLL).[[4]],[[5]] These changes significantly narrow the spinal canal and reduce the space available
for the spinal cord. As societies continue to age over coming decades, the prevalence
of this common spinal disease is expected to increase among the population.[[6]],[[7]]
Surgical decompression is the gold standard procedure for preventing the progression
of neurological deficits in patients with CSM.[[2]],[[8]],[[9]] However, the efficacy of posterior laminectomy in the surgical management of CSM
has been described in the past but long-term follow-up data in the Indian subcontinent
are scanty.
The aim of the study is to evaluate the long-term efficacy with clinical-radiological
outcomes of posterior cervical decompression without fusion in patients with multilevel
degenerative CSM.
Materials and Methods
After obtaining permission from the ethical committee and hospital management, a retrospective
analysis of 110 patients with degenerative multilevel CSM who underwent posterior
cervical laminectomy alone in a single hospital by a single surgeon from 2004 to 2013
with minimum 5-year follow-up was done. Demographic data (age, sex, duration of illness
to presentation, and comorbidities), pre- and post-operative clinical parameters (neck
pain score-visual analog scale [VAS], Nurick grading and modified Japanese orthopedic
association [mJOA]), radiological parameter (Sagittal cervical Cobb's Angle), perioperative
complications (operative time, blood loss, and hospital stay), postoperative complications
(infection, C5 root palsy, and neurological worsening) were evaluated [[Figure 1]], [[Figure 2]], [[Figure 3]].
Figure 1: Graphical diagram neurology (pre and postoperative)
Figure 2: Postoperative cervical Cobb's angle changes
Figure 3: A 53-year-old male immediate and postoperative images at 5-year follow-up
Inclusion criteria
Inclusion criteria were as follows:
-
Age 45 years and above
-
Compression at level 3 or more
-
Minimum follow-up of 5 years
-
Cobb's angle >10° lordotic (C2–C7) measured on standing lateral cervical spine radiography.
Exclusion criteria
Exclusion criteria were as follows:
-
OPLL
-
Disc herniation
-
Infection
-
Neoplastic disease
-
Rheumatoid arthritis or ankylosing spondylitis
-
Patient who underwent anterior surgeries, posterior surgery with fusion, or revision
surgery
-
Developmentally narrow canal (canal diameter <12 mm at the base of C2).
Patients were sequentially followed up at 3 months, 6 months, 12 months, and 2 years
after surgery and then annually.
Surgical procedure
Under general anesthesia, the patient is positioned prone on padded bolsters. The
neck is placed in neutral or in mild flexion. The arms are strapped by the side. A
standard midline posterior exposure from C3 to C6 is carried out up to the lamina-facet
junction taking care to preserve the attachments to C2 and C7. The dissection is restricted
just lateral to the lamina-facet junction and the soft tissues attachments over the
facet joints are preserved. The furrow at the junction of the lamina and the facet
joints is marked at all levels requiring laminectomy. The gutters were created on
both sides using a high-speed cutting burr till the inner cortex were reached. 1-mm
Kerrison rongeur was used to remove the flavum up to the lateral gutters created.
The rongeur was used to complete the furrows on either side all the way up to the
C2–C3 interlaminar space. The laminectomy was completed by lifting the laminae en
bloc from the caudal end, and gentle dissection was performed for any adhesion between
the ligamentum flavum and dura. Undercutting of C2 and C7 laminae with foraminotomy
of C5 was done to provide adequate decompression.
Postoperative patients are encouraged to sit up in bed 24 h after the surgery. Patients
are mobilized out of bed on the 2nd postoperative day using a soft cervical collar
which was discontinued after suture removal.
The statistical analysis was carried out using a paired student t-test. Differences
were considered statistically significant at P < 0.05. Statistical analysis was done
using SPSS software 20.0 (SPSS Inc., Chicago, IL, USA).
Discussion
Surgical decompression is the gold standard procedure for preventing the progression
of neurological deficits in patients with CSM,[[2]],[[8]],[[9]] and among the available techniques, laminoplasty is generally as most effective
surgical option with lowest risk of perioperative complication.[[10]],[[11]],[[12]] However, surgical results for laminoplasty remain unclear in elderly patients.
Several reports have revealed a comparable degree of neurological recovery between
elderly and younger patients.[[13]],[[14]],[[15]],[[16]],[[17]],[[18]]
In multilevel degenerative CSM, anterior approach carries more morbidities following
multilevel corpectomies and reconstructions, increased blood loss and surgical time,
fusion-related complications, and subsidence. Research in the fusion surgery has shown
that elderly patients have higher mortality, postoperative complications, and bony
nonunion rates than younger patients.[[19]],[[20]] Puvanesarajah et al.[[21]] also demonstrate significantly increased rates of surgical complications and mortality
after anterior cervical fusion.
Posterior cervical laminectomy has assumed an irreplaceable role in preventing symptomatic
progression of CSM, but emerging alternative procedure filed controversy among surgeons.[[22]],[[23]]
Several comparative studies between procedures have already been done; like Hamanishi
and Tanaka reported on their experience in patients with CSM who underwent laminectomy
and fusion; and patients who underwent laminectomy alone, they did not observe any
significant difference in functional status between the groups.[[24]] Lad et al. retrospectively reviewed a total of 2385 patients with decompression
only and 620 patients with fusion and found that complication rates of the initial
procedure hospitalization, and at 90 days were significantly higher for those who
underwent laminectomy with fusion comparing with those who underwent laminectomy alone.[[25]]
The most described drawback regarding posterior cervical decompression by laminectomy
involves the induction of kyphotic changes in postoperative cervical sagittal balance
with increased risk of long-term instability; therefore, some authors recommended
complimentary fusion as a preventive strategy significantly increasing the cost of
the procedure, operative time, blood loss, and adds specific risk for complications.[[24]],[[25]],[[26]]
Ryken et al. mentioned clinical improvement after cervical laminectomy ranges from
42%–90% and also mentioned the duration of symptoms was identified as a predisposing
variable since patients with asymptomatic period over 12 months reached lower long-term
mean score values. However, there is no significant difference in the functional status
variation and surgery enables a functional improvement concerning myelopathy regardless
of disease progression time.[[27]],[[28]]
Kaptain et al. reported on 46 patients undergoing laminectomy who had pre- and post-operative
radiographic and concluded that the development of a postoperative deformity (kyphosis)
was more than twice as likely in patients with a “straight” preoperative spine (loss
of lordosis) than in those with a normal lordosis.[[28]]
Regarding complications, van Geest et al. identified a rate of 9% comprising postoperative
C5 radiculopathy and superficial wound infection that is, consistent with the literature;[[29]] these rates strengthen the role of cervical laminectomy as a safe procedure with
low morbidity.
Bartels et al., published a small clinical randomized trial comparing nine patients
underwent laminectomy and nine patients underwent laminectomy and fusion. They did
not find a difference in the neurologic outcome or quality of life between the groups
at an average follow-up of 18.3 months. These results suggest that laminectomy alone
may be safe and effective in patients with preserved cervical lordosis and a stable
cervical spine, without preoperative spinal instability, in whose decompression would
not involve the facet joints, C2 lamina or the cervicothoracic junction.[[30]]
According to Du et al. study, 30 patients underwent laminectomy alone and 30 patients
for laminectomy and fusion and reported that loss of curvature index with a high incidence
of axial neck symptoms in laminectomy group.[[31]]
Heller et al. performed a matched cohort study in 26 patients with CSM who underwent
either by laminoplasty or laminectomy with lateral mass fixation and grafting. The
author reported no significant difference in neurological recovery, postoperative
axial neck pain, and complication rate between two groups. Radiologically also, no
difference in cervical alignment postoperative, although severe kyphosis developed
in one patient who underwent fusion.[[32]]
With Woods et al., 82 patients underwent decompression with fusion surgery and 39
patients underwent decompression alone and reported that similar functional improvement
in both groups. However, 7 (9%) patient had complications in decompression and fusion
with 2 (2%) patients required revision surgery as compared to 5 (13%) patient had
complications in decompression alone with 2 (5%) patients required revision surgery.[[33]]
Therefore, our study shows that posterior cervical decompression without fusion in
multilevel degenerative CSM patients yields a significant improvement in clinical
status even in long-term follow-up period. Fifteen patients who developed cervical
kyphosis and 32 patients who developed straightening of the cervical spine at final
follow-up which may be contributed to lesser preoperative lordotic Cobb's angle. Furthermore,
over 85% of patients was satisfied with the outcome that favors the effect of surgery
in their daily lives.
Limitation of this study is the retrospective nature of the data collected which can
lead to some bias in the results.
Conclusions
With proper selection of patients, posterior cervical laminectomy is effective in
offering a clinical improvement to patients with multilevel degenerative CSM in long
term even though there are changes in cervical alignment.
