Open Journal of Mo dern Neurosurgery, 2011, 1, 5-9
doi:10.4236/ojmn.2011.12002 Published Online October 2011 (http://www.SciRP.org/journal/ojmn)
Spine Surgery Profile in the Fourth Age
Mohammad Sami Walid, Priyal Shah, Moataz Abbara, Nadezhda Zaytseva
Department of Medic al Education & Research, Medical Center of Central Georgia,
Macon, Georgia, USA
Received August 1, 2011; revised August 25, 2011; accepted September 5, 2011
Abstract
As the population of the United States undergoes significant qualitative and quantitative changes the health-
care needs of the population changes accordingly. Since the “old-old” ≥85 years sector of the population is
growing fast we embarked on studying how spine surgery profile changes across age groups. Methods: A
database of 6147 spine surgery patients operated in a tertiary care center in Middle Georgia between 2003
and 2009 was divided to four age groups. The threshold for old-old age was set at 75. The percentage of
old-old patients was calculated and their spine surgery profile for the whole period was studied. Changes in
spine surgery profile were evaluated in relation to age group and gender. Type of surgery was determined by
ICD-9 code. Results: For the whole study period, the percentage of old-old spine surgery patients was 6.7%.
The percentage of old-old spine surgery patients increased from 4.7% in 2003 to 7.3% in 2009. Females
were preponderant in the later three age groups (53.8%, 53.2% and 55.0%) while males were more in the
<40 group (52.8%). Significant differences in the spine surgery profile between age groups were detected
(Χ2 = 1446.958, P = 0.000). The spine surgery profile for the whole study period was characterized by shifts
in the ≥75 age group toward less primary fusions of the cervical and lumbar spine and more refusions of the
lumbar spine, more intervertebral disk excisions and more canal exploratory operations in older-old patients.
In addition to the age factor, the gender factor had an impact on the spine surgery profile. Statistically sig-
nificant differences (P < 0.5) were noted between males and females in each age group. Conclusions: Spine
surgery profile shows a tendency toward less invasive procedures in the older-old population unless indi-
cated by previous surgery failures, upper neck injuries or osteoporosis-induced fractures.
Keywords: Spine Surgery, Fourth Age, Very Old, Old-Old, Older-Old
1. Introduction
As the population of the United States undergoes sig-
nificant qualitative and quantitative changes the health-
care needs of the population change accordingly. Latest
data (July 2009) show that 307.007 million people live in
the United States, 5.722 million of them (July 2008) are
85 years and older, 3.858 million of which are females
[1]. While the total population of the United States in-
creased by 0.4 fold over 19 years (from 226.542 million
in July 1980), the ≥85 age group more than doubled dur-
ing this period (from 2.271 million in July 1980, Figure
1).
The ≥85 age group (and in some references ≥75) has
recently been dubbed “the Fourth Age”, “the very old”,
or “the old(er)-old” [2-5]. Since the senior sector of the
Western population is growing rapidly, owing to better
healthcare services and improved longevity, we at-
tempted to study the spine surgery profile of this patient
population compared with other age groups.
2. Materials & Methods
A database of 6147 spine surgery patients operated in a
tertiary care center in Middle Georgia between 2003 and
2009 was divided per age. Four age groups were demar-
cated and the threshold for old-old group was set at 75
[6,7]. Some references use 80 or 85 years as a threshold,
pointing to lack of consensus on the definition of this
new terminology [5,8,9].
The percentage of old-old patients was calculated and
their spine surgery profile for the whole period was

M. S. WALID ET AL. 6
Figure 1. Growth of the U.S. senior population. Data source: U.S. Census Bureau. Graph source: Google public data ex-
plorer.
studied. Spine surgery profile for a cohort of patients was
defined as the distribution of spine surgical interventions
for the named cohort per type of procedure. Changes in
spine surgery profile were studied in relation to age
group and gender. Type of surgery was determined by
ICD-9 code. Percentages were statistically compared
using Pearson Chi-square analysis.
3. Results
3.1. Growing Old-Old Percentage
For the whole study period, the largest group (51.1%)
was the 40 - 59 age group. The percentage of old-old
spine surgery patients (≥75 years old) was 6.7% (Figure
2). Over the years, the percentage of old-old spine sur-
gery patients increased from 4.7% in 2003 to 7.3% in
2009. Females were preponderant in the later three age
groups (53.8%, 53.2% and 55.0%) while males were
more in the <40 group (52.8%).
3.2. Summated Spine Surgery Profile
In the whole cohort for the whole study period, the top
five surgical procedures were:
 Anterior cervical decompression and fusion (40.7%).
 Lumbar/Lumbosacral fusion, lateral approach (19.2%).
 Excision of intervertebral disk (15.0%).
 Spinal canal exploration (8.3%).
 Lumbar/Lumbosacral fusion, posterior approach
(5.7%).
3.3. Spine Surgery Profile across Age
Significant differences in the spine surgery profile be-
Figure 2. Patient database divided per age group and gen-
der.
tween age groups were detected (Χ2 = 1446.958, P =
0.000). The spine surgery profile of the ≥75 age group
was characterized by a relative increase in the following
procedures:
 Spinal canal exploration (from 3.1% in patients <40
to 26.7% in patients ≥75).
 Insertion or replacement of interspinous device (from
0.4% in patients <40 to 26.8% in patients ≥75).
 Excision of intervertebral disk (from 17.8% in pa-
tients <40 to 23.7% in patients ≥75).
 Implantation of interspinous process decompression
device (from 0.0% in patients <40 to 3.9% in patients

M. S. WALID ET AL.7
≥75).
 Vertebral fracture repair (from 1.7% in patients <40
to 2.7% in patients ≥75).
 Atlas-axis fusions (from 0.5% in patients <40 to 1.2%
in patients ≥75).
 Reopening laminectomy site (from 0.0% in patients
<40 to 0.5% in patients ≥75).
 Refusion of lumbar, lateral or posterior (from 0.0% in
patients <40 to 0.5% in patients ≥75).
On the other hand, the following procedures relatively
decreased in the ≥75 age group:
 Anterior cervical fusion (from 36.0% in patients <40
to 14.7% in patients ≥75).
 Lumbar and lumbosacral fusions, lateral (from 17.1%
in patients <40 to 7.8% in patients ≥75).
 Lumbar and lumbosacral fusions, posterior (from
6.4% in patients <40 to 5.1% in patients ≥75).
 Dorsal/dorsolumbar fusion, posterior (from 5.3% in
patients <40 to 1.2% in patients ≥75).
 Spinal structure repair (from 3.5% in patients <40 to
0.2% in patients ≥75).
 Dorsal/dorsolumbar and lumbar/lumbosacral fusions,
anterior (from 0.7% in patients <40 to 0.0% in pa-
tients ≥75).
Summarizing the above-mentioned trends, it is evident
that the spine surgery profile changes toward less pri-
mary fusions of the cervical and lumbar spine and more
refusions of the lumbar spine, more intervertebral disk
excisions and more canal exploratory operations in older-
old patients (Figure 3).
In addition to the age factor, the gender factor has an
impact on the spine surgery profile. Statistically signifi-
cant differences (P < 0.5) were noted between males and
females in each age group (Figure 4). Older-old female
Figure 3. Spine surgery profile for a database of spine surgery patients divided per age group. Procedures in the <40 group
sorted in descending order.

M. S. WALID ET AL. 8
Figure 4. Spine surgery profile for a database of spine surgery patients divided per age group and gender. Procedures in the
<40 female group sorted in desce nding or de r.
patients had more lumbar fusions (11.1% vs. 3.8 for lat-
eral; 7.1% vs. 2.7% for posterior), more interspinous
devices (8.0% vs. 5.4%) and more vertebral fracture re-
pairs (3.1% vs. 2.2%). Older-old female patients had
fewer excisions of intervertebral disks (19.6% vs. 28.8%)
and less canal exploratory operations (25.3% vs. 28.3%).
4. Commentary
Aging has always been synonymous in the traditional
people’s imagination with decreased functionality, in-
creasing pain, fear of disability and impending death [10].
Current developments in technology and surgery have to
some extent challenged this concept by extending length
of human life and improving quality of everyday living.
The share of the old-old is expected to grow twice as fast
as the conventional old group in the coming decades [10].
This qualitative change in the population’s composition
is accompanied by a parallel increase in demand for
healthcare services related to degenerative and chronic
diseases, including degenerative spine disease and chro-
nic back pain.
The old-old subgroup of the senior population presents
their own needs as their functional reserves rapidly de-
cline and the capacity to self-repair becomes extremely
impaired. The demand for spine surgery in the old-old is
therefore characterized by higher requirement for ex-
plorative decompressive interventions with the least pos-
sible trauma. Decompressive procedures are less invasive
than fusion procedures and are mostly done through
laminectomy and less frequently with the help of an in-
terspinous device. Other types of fusions that increase in
the older-old are refusion procedures performed to cor-
rect complications, namely pseudoarthrosis, resulting

M. S. WALID ET AL.9
from previous fusion attempts. Atlas-axis fusions also
increase in older-old patients due to a comparatively
elevated risk of upper cervical spine injuries in elderly
patients [11]. Female old-old patients unsurprisingly
present with higher frequency of vertebral fracture acci-
dents and therefore require more such repairs due to
higher prevalence of osteoporosis [7]. The relatively
higher occurrence of dorsal/dorsolumbar fusions and
spine structure repair operations in the <40 age group
could be related to more frequent traumatic and congeni-
tal etiology in younger age. The preponderance of fe-
males patients in the later three age groups and males in
the younger group reflects the fact that younger males
are subject to suffer more professional spine injuries
while females have better longevity and the longer they
live the higher the risk of osteoporosis.
In summary, the spine surgery profile of our patients
shows a tendency toward less invasive procedures in the
older-old population unless indicated by previous sur-
gery failures, upper neck injuries or osteoporosis-induced
fractures.
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