Technical Appendix
Mehrotra et al., "Evaluation of a Center of Excellence Program for Spine Surgery"
The purpose of this technical appendix is to provide detail about the methods and results that
could not be included in the manuscript. The appendix includes the following tables:
Table 1: Definition of Primary Spine Surgery Categories Used in Analysis
Table 2: Classification of Primary Spine Surgeries: ICD-9-CM Procedure and Diagnosis and
CPT Codes
Table 3: Patient Categories Excluded from Analytic Sample, Time Periods, and Rationale
Table 4. ICD-9-CM Diagnosis and Procedure Codes Used to Identify Patient Categories
Excluded from Analytic Sample
Table 5. Cervical Simple Fusion: Number of Patients in Analytic Sample after Each Exclusion,
by Designation Status, July 2007 - September 2009
Table 6: Lumbar Simple Fusion: Number of Patients in Analytic Sample after Each Exclusion,
by Designation Status, July 2007 - September 2009
Table 7. Lumbar Discectomy/Decompression: Number of Patients in Analytic Sample after Each
Exclusion, by Designation Status, July 2007 - September 2009
Table 8. Specifications for Identifying Complications Following Cervical Simple Fusion,
Lumbar Simple Fusion, or Lumbar Discectomy/Decompression
Table 9. ICD-9-CM Procedure Codes To Be Used in Identifying Wound Complications
Table 10. ICD-9-CM Diagnosis and Procedure Codes and Time Period for Identifying
Readmissions Following Cervical Simple Fusion, Lumbar Simple Fusion, or Lumbar
Discectomy/Decompression
Table 11. Clinical Risk Factor Categories Used in Multivariate Models with Condition Category
(CC) Numbers
Table 12. Prevalence of Medical Conditions* Among Patients With Cervical Simple Fusion,
Lumbar Simple Fusion, or Lumbar Discectomy/Decompression by Designation Status
Table 13. Sensitivity Analyses: Comparison of 90 Day Medical Costs (in Dollars) Using a
Different Method
Table 14. Number of Spine Surgeries Performed in Designated Hospitals and Other Hospitals by
Type of Surgery Before Exclusions, July 2007-September 2009
1
Table 1. Definition of Primary Spine Surgery Categories Used in Analysis
Spine Surgery Category
Cervical Simple Fusion with or
without Cervical discectomy or
Cervical decompression




Lumbar Simple Fusion with or
without a Lumbar discectomy or
Lumbar decompression




Lumbar Discectomy or Lumbar
decompression without Lumbar
fusion



Subcategories
(Cervical simple fusion ) and not (Cervical discectomy or Cervical
decompression)
(Cervical simple fusion and Cervical discectomy and Cervical
decompression)
(Cervical simple fusion and Cervical discectomy) and not
(Cervical decompression)
(Cervical simple fusion and Cervical decompression) and not
(Cervical discectomy)
(Lumbar simple fusion ) and not (Lumbar discectomy or Lumbar
decompression)
(Lumbar simple fusion and Lumbar discectomy and Lumbar
decompression)
(Lumbar simple fusion and Lumbar discectomy) and not (Lumbar
decompression)
(Lumbar simple fusion and Lumbar decompression) and not
(Lumbar discectomy)
Lumbar discectomy and not (Lumbar simple fusion or Lumbar
complex fusion or Lumbar decompression)
Lumbar decompression and not (Lumbar simple fusion or Lumbar
complex fusion or Lumbar discectomy)
(Lumbar discectomy and Lumbar decompression) and not
(Lumbar simple fusion or Lumbar complex fusion)
2
Table 2. Classification of Primary Spine Surgeries: ICD-9-CM Procedure and Diagnosis
and CPT Codes
Spine Surgery
Category
Cervical Spine
Surgery
Cervical simple
fusion
Cervical
complex fusion
Cervical
discectomy
Cervical
Decompression
Lumbar Spine
Surgery
Lumbar simple
fusion
Lumbar
complex fusion
Lumbar
discectomy
Lumbar
decompression
ICD-9-CM Procedure
Codes
(81.02 or 81.03) AND
NOT (CERVICAL
FUSION, COMPLEX)
[(81.02 AND 81.03)] or
[(81.02 or 81.03) AND
(81.63 or 81.64)]
80.51 (requires a diagnosis
code in the next column to
identify as cervical)
03.09 (requires a diagnosis
code in the next column to
identify as cervical)
(81.06 or 81.07 or 81.08)
AND NOT (LUMBAR
FUSION, COMPLEX)
[(81.06) AND (81.07 or
81.08)] or [(81.06 or 81.07
or 81.08) AND (81.63 or
81.64)]
80.51 (requires a diagnosis
code in the next column to
identify as lumbar)
03.09 (requires a diagnosis
code in the next column to
identify as lumbar)
ICD-9-CM Diagnosis Codes
One of the following diagnosis codes must be used to
classify discectomy as cervical (SooHoo, personal
communication, 2010): 721.0, 721.1, 722.0, 722.4,
722.71, 722.91, 723.0, 723.1
One of the following diagnosis codes must be used to
classify decompression as cervical (SooHoo, personal
communication, 2010): 721.0, 721.1, 722.0, 722.4,
722.71, 722.91, 723.0, 723.1
One of the following diagnosis codes must be used to
classify discectomy as lumbar (Weinstein et al., 2006):
722.10, 722.73; 721.3, 722.52, 722.93; 721.42, 724.02;
756.11; 722.32, 724.2
One of the following diagnosis codes must be used to
classify decompression as lumbar (Weinstein et al.,
2006): 722.10, 722.73; 721.3, 722.52, 722.93; 721.42,
724.02; 756.11; 722.32, 724.2
3
Table 3: Patient Categories Excluded from Analytic Sample, Time Periods, and Rationale
Exclusion Category
Time Period
Any refusion spine surgery during index stay
 Index stay1
Surgery performed on multiple levels of the spine, including cases
identified by the following pseudocode:
((Any Cervical=1 and Any Thoracic=1) OR
(Any Cervical=1 and Any Lumbar=1) OR
(Any Thoracic=1 and Any Lumbar=1) OR
(Any Cervical=1 and Any Thoracic=1 and Any Lumbar=1))
Enrollee’s address out of country: Exclude other countries and US
territories (GU-Guam, PR-Puerto Rico, and VI-Virgin Islands)
Address of the index hospital is in a state in which no hospitals
applied to the program: Alaska (AK), Delaware (DE), Mississippi
(MS), Oklahoma (OK), Vermont (VT), West Virginia (WV), and
Wyoming (WY).
 Index stay
Pregnancies2
 Index stay
Refusion spine surgery listed as a secondary procedure on index
hospitalization claim
 Index stay
Another primary or refusion spine surgery in prior six months
 6 months before index
procedure date
Repeat procedure: The CPT modifier codes, 76 (repeat procedure by
same physician) and 77 (repeat procedure by another physician),
indicate the procedure was repeated.
 Professional claim for
index stay
 Index stay
 Index stay
1
Rationale
Refusion procedures are much less common and more
heterogeneous with regard to the indication and type of
procedure, making adequate control in the analysis
difficult.
Surgeries on multiple levels of the spine are excluded
because the cost and outcomes of the procedure might
differ from surgeries performed at one level.
This requirement ensures all claims and costs are captured.
Care outside of the US might be fundamentally different.
No hospitals in these states applied to the center of
excellence program. There was concern that hospitals in
these states were not actively recruited to participate. We
therefore excluded all hospitals in these states because we
did not want to mis-categorize hospitals that met the
designation criteria as non-designated hospitals. Such
miscategorization would bias the results to the null.
Surgeries on pregnant patients are excluded because the
cost and outcomes of the procedure might differ from
other patients.
Patients with a refusion spine surgery listed as a secondary
procedure would be likely to have different complication
and readmission rates.
Patients with another primary or refusion spine surgery in
prior six months would be likely to have different
complication and readmission rates.
As with refusion procedures, repeat procedures are much
less common and more heterogeneous with regard to the
indication and type of procedure, making adequate control
An index stay refers to the hospital stay during which the index procedure (i.e., cervical simple fusion) was performed.
Previous studies of outcomes and complications following spine surgery have excluded patients who are pregnant (Cook 2008; Wang, 2007; Wang 2009;
AHRQ 2009).
2
4
Exclusion Category
Time Period
Spinal cord injuries, fractures of the spinal column, vertebral
dislocations, motor vehicle and other accidents, pathologic
fractures, all malignant neoplasms 3
 6 months before index
procedure date PLUS
 Index stay
Disc prosthesis, cervical


Disc prosthesis, lumbar


Use of bone morphogenetic protein (BMP)


Congenital disorders (spina bifida, certain congenital
musculoskeletal deformities of spine, other congenital
musculoskeletal deformities, anomalies of spine)4

Ankylosing spondylitis and other inflammatory spondylopathies 5



Index stay
Exclude these from
cervical simple fusion
sample only
Index stay
Exclude these from
lumbar simple fusion
sample and lumbar
discectomy and
decompression
sample only
Index stay
Exclude these from
lumbar discectomy
and decompression
sample only
6 months before
index procedure date
PLUS
Index stay
6 months before
index procedure date
PLUS
Index stay
3
Rationale
in the analysis difficult.
Cases with these conditions were excluded to eliminate
non-elective procedures. These are very different types of
cases from a clinical perspective. These exclusions are
consistent with prior literature.,
Disc prosthesis procedures are much less common and
more heterogeneous with regard to the indication and type
of procedure, making adequate control in the analysis
difficult.
Disc prosthesis procedures are much less common and
more heterogeneous with regard to the indication and type
of procedure, making adequate control in the analysis
difficult.
BMP is indicated for fusion procedures, not discectomy
and decompression procedures.
Cases with these conditions were excluded to eliminate
non-elective procedures. These are very different types of
cases from a clinical perspective. These exclusions are
consistent with prior literature.
Cases with these conditions were excluded to eliminate
non-elective procedures. These are very different types of
cases from a clinical perspective. These exclusions are
consistent with prior literature.
Previous studies of outcomes and complications following spine surgery have excluded traumatic spinal cord injury or vertebral fractures (Browne 2007; Cook
2007; Cook 2008; Deyo 2010; Wang, 2007; Wang 2009), and malignancies (Browne 2007; Cook 2007; Cook 2008; Deyo 2010; Wang 2007).
4
Previous studies of outcomes and complications following spine surgery have excluded congenital disorders (e.g., spina bifida) (Browne 2007).
5
Previous studies of outcomes and complications following spine surgery have excluded inflammatory spondyloarthropathies (Deyo 2010; Wang, 2007; Wang
2009).
5
Exclusion Category
Abscess or osteomyelitis6
Time Period


Postlaminectomy syndrome associated with a mechanical
complication of an internal device or graft 7


6 months before
index procedure date
ONLY
DO NOT INCLUDE
INDEX STAY
6 months before
index procedure date
ONLY
DO NOT INCLUDE
INDEX STAY
Index stay
Hospitalizations in which patient was admitted through the
emergency department (admit_type_code=emergency department)

Hospitalizations in which patient left against medical advice
(discharge_status_code =07)
Place of service not inpatient hospital
 Index stay
Not continuously enrolled from 6 months before procedure to 3
months after: Patients who die within 3 months after the procedure
were not excluded.
Primary insurance is not provided by one of the health plans .in the
center of excellence initiative.
Patient <18 years of age at time of index procedure
 From 6 months before
to 3 months after index
procedure
 Index stay
Age 65 years or older at time of index procedure
 Index stay
 Index stay
 Index stay
6
Rationale
Cases with these conditions were excluded to eliminate
non-elective procedures. These are very different types of
cases from a clinical perspective. These exclusions are
consistent with prior literature.
Cases with this condition were excluded to eliminate nonelective procedures. Clinically these are very different
types of cases and these exclusions are consistent with
prior literature.
Cases with these conditions were excluded to eliminate
non-elective procedures. These are very different types of
cases from a clinical perspective. These exclusions are
consistent with prior literature.
Although rare, the costs and outcomes of these
hospitalizations are likely very different.
These cases were excluded because acute care inpatient
hospitals are the focus of this study.
This requirement ensures all claims and costs are captured.
These patients were excluded because it might not be
possible to capture all of their claims and costs.
These types of spine surgeries in persons <18 years of age
are rare and have different clinical indications.
These patients were excluded because it might not be
possible to capture all of their claims and costs due to
Medicare coverage.
Previous studies of outcomes and complications following spine surgery have excluded spine-related infections (Browne 2007; Cook 2007; Cook 2008; Deyo
2010).
7
Previous studies of outcomes and complications following spine surgery have excluded mechanical complications (Cook 2007).
6
Table 4. ICD-9-CM Diagnosis and Procedure Codes Used to Identify Patient
Categories Excluded from Analytic Samples
Exclusion Category and Code
Type of Code
Spine Refusion
81.32
81.33
81.34
81.35
81.36
81.37
81.38
81.63
81.64
Use of bone morphogenetic protein (BMP)
84.52
Disc prosthesis, cervical
84.60
84.61
84.62
Disc prosthesis, lumbar
84.60
84.64
84.65
ICD-9-CM Procedure
ICD-9-CM Procedure
ICD-9-CM Procedure
ICD-9-CM Procedure
ICD-9-CM Procedure
ICD-9-CM Procedure
ICD-9-CM Procedure
ICD-9-CM Procedure
ICD-9-CM Procedure
ICD-9-CM Procedure
ICD-9-CM Procedure
ICD-9-CM Procedure
ICD-9-CM Procedure
ICD-9-CM Procedure
ICD-9-CM Procedure
ICD-9-CM Procedure
Congenital Disorders
741.0x-741.9x
754.2
756.10-756.19
Fractures of spinal column
805.0x
805.1x
805.2
805.3
805.4
805.5
805.6
805.7
805.8
805.9
Spinal Cord Injuries
806.0x
806.1x
806.2x
806.3x
806.4
806.5
806.6x
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
7
Exclusion Category and Code
806.7x
806.8
806.9
952.0x
952.1x
952.3
952.4
952.5
952.8
952.9
Pathological fracture
733.1
733.10
733.13
733.95
733.8
733.81
733.82
Vertebral dislocations
839.0x
839.1x
839.2x
839.3x
839.4x
839.5x
Postlaminectomy syndrome associated with a mechanical
complication of an internal device or graft
722.80
722.81
722.82
722.83
Abscess or Osteomyelitis
324.1
324.9
730.0x
730.1x
730.2x
730.3x
730.7x
730.8x
730.9x
Ankylosing spondylitis and other inflammatory spondylopathies
720.0
720.1
720.2
720.8x
720.9
Pregnant/Pregnancy, childbirth, puerperium
8
Type of Code
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
Exclusion Category and Code
V22.x
V23.xx
630-676.xx
Motor Vehicle and Other Accidents
E800-E848
Malignant neoplasms
140-172.x
174-239.x
Surgery performed on multiple levels of the spine
(Any Cervical=1 and Any Thoracic=1) OR (Any Cervical=1 and Any
Lumbar=1) OR (Any Thoracic=1 and Any Lumbar=1) OR (Any
Cervical=1 and Any Thoracic=1 and Any Lumbar=1)
9
Type of Code
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
ICD-9-CM Diagnosis
Table 5. Cervical Simple Fusion: Number of Patients in Analytic Sample after Each Exclusion, by Designated Status, July
2007 - September 2009
Initial sample size
Surgery performed on multiple levels of the
spine
Any refusion spine surgery during index stay
Enrollee’s address out of country: Exclude
other countries and US territories (GUGuam, PR-Puerto Rico, and VI-Virgin
Islands)
Address of the index hospital is in a state in
which there were no designated hospitals:
Alaska (AK), Delaware (DE), Mississippi
(MS), Oklahoma (OK), Vermont (VT), West
Virginia (WV), and Wyoming (WY).
Pregnancies
Refusion spine surgery listed as a secondary
procedure on index hospitalization claim
Another primary or refusion spine surgery in
prior six months
Repeat procedure: The CPT modifier codes, 76
(repeat procedure by same physician) and 77
(repeat procedure by another physician),
indicate the procedure was repeated.
Spinal cord injuries
Fractures of the spinal column
Vertebral dislocations
Motor vehicle and other accidents
Pathological fractures
Disc prosthesis, cervical
Malignant neoplasms
Designated Hospitals
Sample
% of
Size
Initial
Number
After
Sample
Excluded Exclusion
Size
17,237
100.0%
Other Hospitals
Sample
% of
Size
Initial
Number
After
Sample
Excluded Exclusion
Size
25,225
100.0%
Number
Excluded
Total
Sample
Size
After
Exclusion
42,462
% of
Initial
Sample
Size
100.0%
292
33
16,945
16,912
98.3%
98.1%
417
47
24,808
24,761
98.3%
98.2%
709
80
41,753
41,673
98.3%
98.1%
5
16,907
98.1%
4
24,757
98.1%
9
41,664
98.1%
116
4
16,791
16,787
97.4%
97.4%
1,199
3
23,558
23,555
93.4%
93.4%
1315
7
40,349
40,342
95.0%
95.0%
68
16,719
97.0%
66
23,489
93.1%
134
40,208
94.7%
25
16,694
96.8%
41
23,448
93.0%
66
40,142
94.5%
93
182
343
92
2
53
39
276
16,601
16,419
16,076
15,984
15,982
15,929
15,890
15,614
96.3%
95.3%
93.3%
92.7%
92.7%
92.4%
92.2%
90.6%
165
234
392
150
2
76
89
299
23,283
23,049
22,657
22,507
22,505
22,429
22,340
22,041
92.3%
91.4%
89.8%
89.2%
89.2%
88.9%
88.6%
87.4%
258
416
735
242
4
129
128
575
39,884
39,468
38,733
38,491
38,487
38,358
38,230
37,655
93.9%
92.9%
91.2%
90.6%
90.6%
90.3%
90.0%
88.7%
10
Designated Hospitals
Sample
% of
Size
Initial
Number
After
Sample
Excluded Exclusion
Size
Congenital disorders (spina bifida, certain
congenital musculoskeletal deformities of
spine, other congenital musculoskeletal
deformities, anomalies of spine)
Ankylosing spondylitis and other inflammatory
spondylopathies
Abscess or osteomyelitis
Postlaminectomy syndrome associated with a
mechanical complication of an internal
device or graft
Hospitalizations in which patient was admitted
through the emergency department
(admit_type_code=emergency department)
Hospitalizations in which patient left against
medical advice (discharge_status_code =07)
Place of service not inpatient hospital
Not continuously enrolled from 6 months
before procedure to 3 months after: Patients
who die within 3 months after the procedure
were not excluded.
Primary insurance is not provided by one of the
health plans .in the center of excellence
initiative.
Patient <18 years of age at time of index
procedure
Age 65 years or older at time of index
procedure
Final sample size (after all exclusions)
Other Hospitals
Sample
% of
Size
Initial
Number
After
Sample
Excluded Exclusion
Size
Number
Excluded
Total
Sample
Size
After
Exclusion
% of
Initial
Sample
Size
76
15,538
90.1%
114
21,927
86.9%
190
37,465
88.2%
11
6
15,527
15,521
90.1%
90.0%
26
4
21,901
21,897
86.8%
86.8%
37
10
37,428
37,418
88.1%
88.1%
1
15,520
90.0%
0
21,897
86.8%
1
37,417
88.1%
315
15,205
88.2%
489
21,408
84.9%
804
36,613
86.2%
5
6
15,200
15,194
88.2%
88.1%
8
14
21,400
21,386
84.8%
84.8%
13
20
36,600
36,580
86.2%
86.1%
967
14,227
82.5%
1,360
20,026
79.4%
2327
34,253
80.7%
1,610
12,617
73.2%
2,674
17,352
68.8%
4284
29,969
70.6%
5
12,612
73.2%
7
17,345
68.8%
12
29,957
70.6%
263
12,349
12,349
71.6%
71.6%
399
16,946
16,946
67.2%
67.2%
662
29,295
29,295
69.0%
69.0%
11
Table 6. Lumbar Simple Fusion: Number of Patients in Analytic Sample after Each Exclusion, by BDC Status, July 2007 September 2009
Initial sample size
Surgery performed on multiple levels of the
spine
Any refusion spine surgery during index stay
Enrollee’s address out of country: Exclude
other countries and US territories (GUGuam, PR-Puerto Rico, and VI-Virgin
Islands)
Address of the index hospital is in a state in
which there were no designated hospitals:
Alaska (AK), Delaware (DE), Mississippi
(MS), Oklahoma (OK), Vermont (VT), West
Virginia (WV), and Wyoming (WY).
Pregnancies
Refusion spine surgery listed as a secondary
procedure on index hospitalization claim
Another primary or refusion spine surgery in
prior six months
Repeat procedure: The CPT modifier codes, 76
(repeat procedure by same physician) and 77
(repeat procedure by another physician),
indicate the procedure was repeated.
Spinal cord injuries
Fractures of the spinal column
Vertebral dislocations
Motor vehicle and other accidents
Pathological fractures
Disc prosthesis, lumbar
Malignant neoplasms
Designated Hospitals
Sample
% of
Size
Initial
Number
After
Sample
Excluded Exclusion
Size
18,711
100.0%
Other Hospitals
Sample
% of
Size
Initial
Number
After
Sample
Excluded Exclusion
Size
28,218
100.0%
Number
Excluded
Total
Sample
Size
After
Exclusion
46,929
% of
Initial
Sample
Size
100.0%
121
76
18,590
18,514
99.4%
98.9%
175
117
28,043
27,926
99.4%
99.0%
296
193
46,633
46,440
99.4%
99.0%
5
18,509
98.9%
9
27,917
98.9%
14
46,426
98.9%
102
0
18,407
18,407
98.4%
98.4%
1,149
1
26,768
26,767
94.9%
94.9%
1,251
1
45,175
45,174
96.3%
96.3%
130
18,277
97.7%
213
26,554
94.1%
343
44,831
95.5%
57
18,220
97.4%
95
26,459
93.8%
152
44,679
95.2%
135
37
206
15
1
116
26
276
18,085
18,048
17,842
17,827
17,826
17,710
17,684
17,408
96.7%
96.5%
95.4%
95.3%
95.3%
94.7%
94.5%
93.0%
325
27
252
19
1
149
47
342
26,134
26,107
25,855
25,836
25,835
25,686
25,639
25,297
92.6%
92.5%
91.6%
91.6%
91.6%
91.0%
90.9%
89.6%
460
64
458
34
2
265
73
618
44,219
44,155
43,697
43,663
43,661
43,396
43,323
42,705
94.2%
94.1%
93.1%
93.0%
93.0%
92.5%
92.3%
91.0%
12
Designated Hospitals
Sample
% of
Size
Initial
Number
After
Sample
Excluded Exclusion
Size
Congenital disorders (spina bifida, certain
congenital musculoskeletal deformities of
spine, other congenital musculoskeletal
deformities, anomalies of spine)
Ankylosing spondylitis and other inflammatory
spondylopathies
Abscess or osteomyelitis
Postlaminectomy syndrome associated with a
mechanical complication of an internal
device or graft
Hospitalizations in which patient was admitted
through the emergency department
(admit_type_code=emergency department)
Hospitalizations in which patient left against
medical advice (discharge_status_code =07)
Place of service not inpatient hospital
Not continuously enrolled from 6 months
before procedure to 3 months after: Patients
who die within 3 months after the procedure
were not excluded.
Primary insurance is not provided by one of the
health plans .in the center of excellence
initiative.
Patient <18 years of age at time of index
procedure
Age 65 years or older at time of index
procedure
Final sample size (after all exclusions)
Other Hospitals
Sample
% of
Size
Initial
Number
After
Sample
Excluded Exclusion
Size
Number
Excluded
Total
Sample
Size
After
Exclusion
% of
Initial
Sample
Size
1,724
15,684
83.8%
2,369
22,928
81.3%
4,093
38,612
82.3%
13
8
15,671
15,663
83.8%
83.7%
26
13
22,902
22,889
81.2%
81.1%
39
21
38,573
38,552
82.2%
82.1%
3
15,660
83.7%
5
22,884
81.1%
8
38,544
82.1%
192
15,468
82.7%
315
22,569
80.0%
507
38,037
81.1%
3
11
15,465
15,454
82.7%
82.6%
9
16
22,560
22,544
79.9%
79.9%
12
27
38,025
37,998
81.0%
81.0%
1,035
14,419
77.1%
1,479
21,065
74.7%
2,514
35,484
75.6%
2,551
11,868
63.4%
4,332
16,733
59.3%
6,883
28,601
60.9%
48
11,820
63.2%
62
16,671
59.1%
110
28,491
60.7%
536
11,284
11,284
60.3%
60.3%
741
15,930
15,930
56.5%
56.5%
1,277
27,214
27,214
58.0%
58.0%
13
Table 7. Lumbar Discectomy/Decompression: Number of Patients in Analytic Sample after Each Exclusion, by BDC Status,
July 2007 - September 2009
Initial sample size
Any refusion spine surgery during index stay
Surgery performed on multiple levels of the
spine
Enrollee’s address out of country: Exclude
other countries and US territories (GUGuam, PR-Puerto Rico, and VI-Virgin
Islands)
Address of the index hospital is in a state in
which there were no designated hospitals:
Alaska (AK), Delaware (DE), Mississippi
(MS), Oklahoma (OK), Vermont (VT), West
Virginia (WV), and Wyoming (WY).
Pregnancies
Refusion spine surgery listed as a secondary
procedure on index hospitalization claim
Another primary or refusion spine surgery in
prior six months
Repeat procedure: The CPT modifier codes, 76
(repeat procedure by same physician) and 77
(repeat procedure by another physician),
indicate the procedure was repeated.
Spinal cord injuries
Fractures of the spinal column
Vertebral dislocations
Motor vehicle and other accidents
Pathological fractures
Disc prosthesis, lumbar
Use of bone morphogenetic protein (BMP)
Malignant neoplasms
Designated Hospitals
Sample
% of
Size
Initial
Number
After
Sample
Excluded Exclusion
Size
20,772
100.0%
155
20,617
99.3%
Other Hospitals
Sample
% of
Size
Initial
Number
After
Sample
Excluded Exclusion
Size
26,736
100.0%
237
26,499
99.1%
392
Total
Sample
Size
After
Exclusion
47,508
47,116
% of
Initial
Sample
Size
100.0%
99.2%
Number
Excluded
162
20,455
98.5%
211
26,288
98.3%
373
46,743
98.4%
4
20,451
98.5%
11
26,277
98.3%
15
46,728
98.4%
166
10
20,285
20,275
97.7%
97.6%
1,061
10
25,216
25,206
94.3%
94.3%
1,227
20
45,501
45,481
95.8%
95.7%
4
20,271
97.6%
13
25,193
94.2%
17
45,464
95.7%
70
20,201
97.3%
89
25,104
93.9%
159
45,305
95.4%
125
1
15
13
1
10
12
29
310
20,076
20,075
20,060
20,047
20,046
20,036
20,024
19,995
19,685
96.6%
96.6%
96.6%
96.5%
96.5%
96.5%
96.4%
96.3%
94.8%
258
0
32
17
1
26
17
27
390
24,846
24,846
24,814
24,797
24,796
24,770
24,753
24,726
24,336
92.9%
92.9%
92.8%
92.7%
92.7%
92.6%
92.6%
92.5%
91.0%
383
1
47
30
2
36
29
56
700
44,922
44,921
44,874
44,844
44,842
44,806
44,777
44,721
44,021
94.6%
94.6%
94.5%
94.4%
94.4%
94.3%
94.3%
94.1%
92.7%
14
Designated Hospitals
Sample
% of
Size
Initial
Number
After
Sample
Excluded Exclusion
Size
Congenital disorders (spina bifida, certain
congenital musculoskeletal deformities of
spine, other congenital musculoskeletal
deformities, anomalies of spine)
Ankylosing spondylitis and other inflammatory
spondylopathies
Abscess or osteomyelitis
Postlaminectomy syndrome associated with a
mechanical complication of an internal
device or graft
Hospitalizations in which patient was admitted
through the emergency department
(admit_type_code=emergency department)
Hospitalizations in which patient left against
medical advice (discharge_status_code =07)
Place of service not inpatient hospital
Not continuously enrolled from 6 months
before procedure to 3 months after: Patients
who die within 3 months after the procedure
were not excluded.
Primary insurance is not provided by one of the
health plans .in the center of excellence
initiative.
Patient <18 years of age at time of index
procedure
Age 65 years or older at time of index
procedure
Final sample size (after all exclusions)
Other Hospitals
Sample
% of
Size
Initial
Number
After
Sample
Excluded Exclusion
Size
Number
Excluded
Total
Sample
Size
After
Exclusion
% of
Initial
Sample
Size
119
19,566
94.2%
155
24,181
90.4%
274
43,747
92.1%
10
6
19,556
19,550
94.1%
94.1%
23
4
24,158
24,154
90.4%
90.3%
33
10
43,714
43,704
92.0%
92.0%
7
19,543
94.1%
5
24,149
90.3%
12
43,692
92.0%
1,005
18,538
89.2%
1,460
22,689
84.9%
2,465
41,227
86.8%
1
9
18,537
18,528
89.2%
89.2%
10
27
22,679
22,652
84.8%
84.7%
11
36
41,216
41,180
86.8%
86.7%
1,103
17,425
83.9%
1,337
21,315
79.7%
2,440
38,740
81.5%
3,120
14,305
68.9%
4,996
16,319
61.0%
8,116
30,624
64.5%
66
14,239
68.5%
90
16,229
60.7%
156
30,468
64.1%
651
13,588
13,588
65.4%
65.4%
906
15,323
15,323
57.3%
57.3%
1,557
28,911
28,911
60.9%
60.9%
15
Table 8. Specifications for Identifying Complications Following Cervical Simple Fusion, Lumbar Simple Fusion, or Lumbar
Discectomy/Decompression
Complication
Acute Myocardial Infarction
ICD-9-CM Diagnosis and Procedure Codes
Presence of one of the following diagnosis codes in a primary or secondary diagnosis field on the
record for the index hospitalization OR in a primary diagnosis field only on a readmission record
with an admission date that falls within the specified time period (see third column):
 410.xx excluding 410.x2
Pneumonia
Presence of one of the following diagnosis codes in a primary or secondary diagnosis field on the
record for the index hospitalization OR in a primary diagnosis field only on a readmission record
with an admission date that falls within the specified time period (see third column):
 480, 480.0, 480.1, 480.2, 480.3, 480.8, 480.9, 481, 482, 482.0, 482.1, 482.2, 482.3,
482.30,482.31, 482.32, 482.39, 482.4, 482.40, 482.41, 482.42, 482.49, 482.81, 482.82,
482.83, 482.84, 482.89, 482.9, 483, 483.0, 483.1, 483.8, 485, 486, 487.0, 507.0
Presence of one of the following diagnosis codes in a primary or secondary diagnosis field on the
record for the index hospitalization or in a primary or secondary diagnosis field on a readmission
record with an admission date that falls within the specified time period (see third column):
 038, 038.0, 038.1, 038.10, 038.11, 038.12, 038.19, 038.2, 038.3, 038.4, 038.40, 038.41,
038.42, 038.43, 038.44, 038.49, 038.8, 038.9, 785.52, 785.59, 790.7, 995.91, 995.92, 998.0,
998.59, 790.7, 998.59
Presence of one of the following diagnosis codes in a primary or secondary diagnosis field on the
record for the index hospitalization or in a primary or secondary diagnosis field on a readmission
record with an admission date that falls within the specified time period (see third column):
 415.1, 415.11, 415.19
Sepsis/Septicemia
Pulmonary Embolism
Death in an acute care hospital or
other facility
Presence of one of the following discharge status codes for the index hospitalization:
CODE
DESCRIPTION
20
Expired
40
Expired at home (hospice care)
41
Expired in a medical facility (e.g.
hospital, SNF, ICF, free standing
hospice)
42
Expired place unknown (hospice
care)
16
Time Period
From admission
date of index
hospitalization to 7
days after admission
date
From admission
date of index
hospitalization to 7
days after admission
date
From admission
date of index
hospitalization to 7
days after admission
date
From admission
date of index
hospitalization to 30
days after admission
date
From admission
date of index
hospitalization to 30
days after admission
date
Complication
Wound Complications following
Cervical Simple Fusion
ICD-9-CM Diagnosis and Procedure Codes
Restrict to cervical simple fusion. DO NOT INCLUDE WOUND COMPLICATIONS THAT
OCCUR DURING THE INDEX HOSPITALIZATION.
Presence of one of the following diagnosis codes:
 Wound infection: 996.67, 998.3, 998.30, 998.31, 998.32, 998.33, 998.5, 998.51, 998.59,
998.6, 998.83
 Osteomyelitis: 730.0, 730.00, 730.1,730.10, 730.20, 730.9, 730.90
 Arthritis-related infection: 711, 711.0, 711.00, 711.6, 711.60, 711.9, 711.90
 Surgical Site Bleeding: 998.1, 998.11, 998.12, 998.13
AND at least one of the following procedure codes (see Table 2 for a complete list of codes):
 Incision and Drainage: 86.22, 86.28, 86.04
 77.6 (local excision of lesion or tissue of bone)
 78.6 (Removal of implant from bone)]
 Removal: 80.09
 Arthrotomy: 80.0, 80.00, 80.1, 80.10
 Procedure/diagnosis code combinations listed in a row in this table (below) labeled "Repeat
Spine Surgery after Cervical Simple Fusion"
 Procedures from a review of procedure codes on facility claims with a wound infection or
surgical site bleeding diagnosis code within 30 days of spine surgery (see Table 9)
17
Time Period
From discharge date
of index
hospitalization to 30
days after admission
date of index
hospitalization
Complication
Wound Complications following
Lumbar Simple Fusion or Lumbar
Discectomy/ Decompression
Repeat Spine Surgery after
Cervical Simple Fusion
ICD-9-CM Diagnosis and Procedure Codes
Restrict to lumbar simple fusion or lumbar discectomy/ decompression. DO NOT INCLUDE
WOUND COMPLICATIONS THAT OCCUR DURING THE INDEX HOSPITALIZATION.
Presence of one of the following diagnosis codes:
 Wound infection: 996.67, 998.3, 998.30, 998.31, 998.32, 998.33, 998.5, 998.51, 998.59,
998.6, 998.83
 Osteomyelitis: 730.0, 730.00, 730.1,730.10, 730.20, 730.9, 730.90
 Arthritis-related infection: 711, 711.0, 711.00, 711.6, 711.60, 711.9, 711.90
 Surgical Site Bleeding: 998.1, 998.11, 998.12, 998.13
AND at least one of the following procedure codes (see Table 2 for a complete list of codes):
 Incision and Drainage: 86.22, 86.28, 86.04
 77.6 (local excision of lesion or tissue of bone)
 78.6 (Removal of implant from bone)
 Removal: 80.09
 Arthrotomy: 80.0, 80.00, 80.1, 80.10
 Procedure/diagnosis codes listed in a row in this table (below) labeled "Repeat Spine Surgery
after Lumbar Simple Fusion or Lumbar Discectomy/Decompression"
 Procedures from a review of procedure codes on facility claims with a wound infection or
surgical site bleeding diagnosis code within 30 days of spine surgery (see Table 9 below)
Restrict to cervical simple fusion.
Presence of at least one of the following procedure codes during a readmission within 90 days after
admission date of index hospitalization:
 Fusion: Presence of at least one of the following procedure codes:81.02, 81.03
 Refusion: Presence of at least one of the following procedure codes:81.32, 81.33
 Discectomy:
 Presence of the following procedure code: 80.51 AND
 Presence of one of the following diagnosis codes: 721.0, 721.1, 722.0, 722.4, 722.71,
722.91, 723.0, 723.1
 Decompression
 Presence of the following procedure code: 03.09 AND
 Presence of one of the following diagnosis codes: 721.0, 721.1, 722.0, 722.4, 722.71,
722.91, 723.0, 723.1
18
Time Period
From discharge date
of index
hospitalization to 30
days after admission
date of index
hospitalization
From discharge date
of index
hospitalization to 90
days after admission
date of index
hospitalization
Complication
Repeat Spine Surgery after Lumbar
Simple Fusion or Lumbar
Discectomy/ Decompression
Any Complication
ICD-9-CM Diagnosis and Procedure Codes
Restrict to lumbar simple fusion or lumbar discectomy/ decompression.
Presence of at least one of the following procedure codes during a readmission within 90 days after
admission date of index hospitalization:
 Fusion: 81.06, 81.07, 81.08
 Refusion: 81.36, 81.37, 81.38
 Discectomy:
 Presence of the following procedure code: 80.51 AND
 Presence of one of the following diagnosis codes: 722.10, 722.73; 721.3, 722.52,
722.93; 721.42, 724.02; 756.11; 722.32, 724.2
 Decompression
 Presence of the following procedure code: 03.09 AND
 Presence of one of the following diagnosis codes: 722.10, 722.73; 721.3, 722.52,
722.93; 721.42, 724.02; 756.11; 722.32, 724.2
Presence of at least one of the seven complications (as defined above)
Time Period
From discharge date
of index
hospitalization to 90
days after admission
date of index
hospitalization
Time periods for the
seven complications
(as defined above)
*Based on information from: Yale New Haven Health Services Corporation/Center for Outcomes Research and Evaluation (YNHHSC/CORE). Form 9.1:
Measure Information Form, Hospital risk-standardized complications rate following elective primary total Knee arthroplasty (THA) and/or total knee
arthroplasty (TKA), Draft. July 15, 2010.
19
Table 9. ICD-9-CM Procedure Codes To Be Used in Identifying Wound Complications
ICD-9-CM
Procedure Code
Incision and Drainage
Description
86.22
Excisional debridement of wound, infection, or burn
86.28
Nonexcisional debridement of wound, infection or burn
86.04
Other incision with drainage of skin and subcutaneous tissue
Miscellaneous codes
77.6
Local excision of lesion or tissue of bone, vertebrae
78.69
Removal of implant from bone, vertebrae
80.09
Arthrotomy for removal of prosthesis, spine
Arthrotomy
80.0
Arthrotomy for removal of prosthesis
80.00
Arthrotomy for removal of prosthesis, site unspecified
80.09
Arthrotomy for removal of prosthesis, spine
80.1
Arthrotomy, other
80.10
Arthrotomy, other, site unspecified
80.19
Arthrotomy, other, spine
"Repeat Spine Surgery after Cervical Simple Fusion"
81.02
Other cervical fusion, anterior technique
81.03
Other cervical fusion, posterior technique
81.32
Refusion of other cervical spine, anterior technique
81.33
Refusion of other cervical spine, posterior technique
80.51
Presence of the following procedure code: 80.51
AND Presence of one of the following diagnosis codes: 721.0, 721.1, 722.0, 722.4, 722.71,
722.91, 723.0, 723.1
03.09
Presence of the following procedure code: 03.09
AND Presence of one of the following diagnosis codes: 721.0, 721.1, 722.0, 722.4, 722.71,
722.91, 723.0, 723.1
"Repeat Spine Surgery after Lumbar Simple Fusion or Lumbar Discectomy/Decompression"
81.06
Lumbar and lumbosacral fusion, anterior technique
20
ICD-9-CM
Procedure Code
81.07
Description
Lumbar and lumbosacral fusion, lateral transverse process technique
81.08
Lumbar and lumbosacral fusion, posterior technique
81.36
Refusion of lumbar and lumbosacral spine, anterior technique
81.37
Refusion of lumbar and lumbosacral spine, lateral transverse process technique
81.38
Refusion of lumbar and lumbosacral spine, posterior technique
80.51
Presence of the following procedure code: 80.51
AND Presence of one of the following diagnosis codes: 722.10, 722.73; 721.3, 722.52, 722.93;
721.42, 724.02; 756.11; 722.32, 724.2
03.09
Presence of the following procedure code: 03.09
AND Presence of one of the following diagnosis codes: 722.10, 722.73; 721.3, 722.52, 722.93;
721.42, 724.02; 756.11; 722.32, 724.2
Selected from Review of Procedure Codes for Stays with a Diagnosis of Wound Infection or Surgical Site
Bleeding within 30 Days of Spine Surgery
02.12
Other repair of cerebral meninges
03.02
Reopening of laminectomy site
03.09
Oth exploration & decompr spinal canal
03.39
Oth diag procs on spinal cord & spinal c
03.4
Excis/destruc lesion spinal cord/spinal
03.59
Oth repair & plastic opers on spinal cor
3.6
03.8
Lysis adhesions spinal cord & nerve root
Injec destructive agent into spinal cana
03.92
Injection of oth agent into spinal canal
3.95
03.99
Spinal blood patch
Oth opers on spinal cord & spinal canal
06.02
Reopening of wound of thyroid field
6.92
Ligation of thyroid vessels
28.0
Incis & drainage tonsil & peritonsillar
38.7
Interruption of the vena cava
38.82
Oth surg occlusion oth vessels head & ne
21
ICD-9-CM
Procedure Code
39.3
Description
Suture of unspecified blood vessel
39.32
Suture of vein
39.57
Repair blood vessel w/synthetic patch gr
39.98
Control of hemorrhage,not othws specd
41.98
54.12
Other operations on bone marrow
Reopening of recent laparotomy site
54.19
Other laparotomy
54.61
Reclosure postoperative disruption abdom
54.91
Percutaneous abdominal drainage
77.19
Oth incis oth bone,except facial bones,w
77.49
Biopsy of oth bone,except facial bones
77.69
Local excis lesion/tis oth bone,except f
77.89
Oth partial ostectomy oth bone,except fa
78.09
Bone graft oth bone,except facial bones
78.59
Int fixation oth bone,except facial bone
78.69
Rem of implanted device from oth bone
80.39
Biopsy joint structure oth specd site
80.5
80.51
Excis/destruc intervertebral disc,unspec
Excision of intervertebral disc
80.89
Oth local excis/destruc lesion joint oth
81.38
Refusion of lumbar post
81.62
Fus/refus 2-3 vertebrae
81.91
Arthrocentesis
83.02
Myotomy
83.09
Other incision of soft tissue
83.14
Fasciotomy
22
ICD-9-CM
Procedure Code
83.19
Description
83.32
Other division of soft tissue
Excision of lesion of muscle
83.39
Excision of lesion of other soft tissue
83.44
Other fasciectomy
83.45
Other myectomy
83.49
Other excision of soft tissue
83.65
Other suture of muscle or fascia
83.77
Muscle transfer or transplantation
83.82
Graft of muscle or fascia
83.95
Aspiration of other soft tissue
84.68
Revise disc prosth lumb
86.01
Aspiration of skin & subcutaneous tissue
86.04
Oth incis w/drainage skin & subcutaneous
86.05
Incis w/rem foreign body fr skin & subcu
86.09
Oth incision of skin & subcutaneous tis
86.22
Excisal debridement wound,infection,or b
86.28
Nonexcisal debridement wound,infection,o
86.3
Oth local excis/destruc lesion/tis skin
86.4
Radical excision of skin lesion
86.59
Closur skin & subcutaneous tis oth sites
86.66
Homograft to skin
86.7
86.72
Pedicle or flap graft,not othws specd
Advancement of pedicle graft
86.74
Attachment pedicle/flap graft to oth sit
86.89
Oth repair & reconstruction skin & subcu
93.56
Application of pressure dressing
23
ICD-9-CM
Procedure Code
93.57
96.59
Description
Application of other wound dressing
Other irrigation of wound
24
Table 10. ICD-9-CM Diagnosis and Procedure Codes and Time Period for Identifying Readmissions Following Cervical
Simple Fusion, Lumbar Simple Fusion, or Lumbar Discectomy/Decompression*
Measure Element
Denominator
ICD-9-CM Diagnosis and Procedure Codes
Patients aged 18 and older admitted to acute care inpatient hospitals for an elective, primary spine surgery.
Patients are eligible for inclusion in the denominator if they have had one of the spine surgeries described in
Table 1 above
Numerator:
Inclusion
Include:
Any readmission to an acute care hospital within 30 days
Numerator
Exclusion: Likely
rehab admissions
**
Time Period
Admission date of index
hospitalization from July 1,
2007 through September 30,
2009
From discharge date of
index hospitalization to 30
days after discharge date
From discharge date of
index hospitalization to 30
days after discharge date
Exclude the following categories:
Readmissions to a different hospital on the same day that are not a discharge or transfer to another short term
hospital:
 samehosp=0 and readmit_interval_1=0 and index_discharge_status_code NE '02:
DISCHARGE/TRANSFER TO ANOTHER SHORT TERM HOSPITAL'
Readmissions to a rehabilitation hospital:
 PROVIDER_SPECIALTY_CODE = 'A1 SKILLED NURSING FACILITY' OR 'A3 NURSING
FACILITY, OTHER' OR '25 PHYSICAL MEDICINE AND REHABILITATION'
Readmissions with a principal diagnosis indicating rehabilitation:
 V57.89 (Other specified rehabilitation procedure, Multiple training or therapy) or any other diagnosis
that begins with a 'V'
* Based on information from: Yale New Haven Health Services Corporation/Center for Outcomes Research and Evaluation (YNHHSC/CORE). Form 9.1:
Measure Information Form, Hospital risk-standardized complications rate following elective primary total Knee arthroplasty (THA) and/or total knee
arthroplasty (TKA), Draft. July 15, 2010.
** This exclusion was developed by the authors.
25
Table 11. Clinical Risk Factor Categories Used in Multivariate Models with Condition
Category (CC) Numbers*
Clinical Risk Factor Category*
Condition Category (CC)#
Infection
Metastatic Cancer and acute leukemia
Cancer
Diabetes and Diabetes Mellitus Complications
Protein-calorie malnutrition
Disorders of Fluid/Electrolyte/Acid-Base
Rheumatoid Arthritis and Inflammatory Connective Tissue Disease
Severe hematological disorders
Dementia and senility
Major psychiatric Disorders
Hemiplegia, paraplegia, paralysis, functional disability
Polyneuropathy
Congestive heart failure
Chronic atherosclerosis
Hypertension
Arrhythmias
Stroke
Vascular or circulatory disease
Copd
Pneumonia
End-stage renal disease or dialysis
Renal failure
Decubitus ulcer or chronic skin ulcer
Cellulites, local skin infection
Other injuries
Major symptoms, abnormalities
CC 1, 3-6
CC 7
CC 8-12
CC 15-20, 119, 120
CC 21
CC 22, 23
CC 38
CC 44
CC 49, 50
CC 54-56
CC 67-69, 100-102, 177-178
CC 71
CC 80
CC 83-84
CC 89, 91
CC 92, 93
CC 95, 96
CC 104-106
CC 108
CC 111-113
CC 129**, 130
CC 131
CC 148, 149
CC 152
CC 162
CC 166
* Based on information from: Yale New Haven Health Services Corporation/Center for Outcomes Research and Evaluation
(YNHHSC/CORE). Form 9.1: Measure Information Form, Hospital risk-standardized complications rate following elective
primary total hip arthroplasty (THA) and/or total knee arthroplasty (TKA), Draft. July 15, 2010.
# The "condition category" (CC) numbers were developed as part of the Centers for Medicare & Medicaid Services
(CMS)-Hierarchical Condition Category (HCC) Model (Pope et al., 2004). Each "condition category" corresponds to a
set of ICD-9-CM codes. The condition categories are defined in a "Condition Category-to-ICD-9-CM Crosswalk"
which was available from the Quality Net website (www.qualitynet.org) on September 4, 2010. The crosswalk file
name is 302_416_2010_ICD_9_Crosswalk.txt (exact URL not available).
**The original article on the HCC model states, "CC 129, ESRD is defined by Medicare entitlement status" (Pope et al.,
2004). However, because we are not analyzing Medicare claims, we were not able to assign CC 129 (End Stage
Renal Disease (Medicare elig)) as originally specified. Therefore, our models contains only one indicator of ESRD,
representing CC 130 (Dialysis Status).
26
Table 12. Prevalence of Clinical Risk Factorsa Among Patients Having Cervical Simple Fusion, Lumbar Simple Fusion, or
Lumbar Discectomy/Decompression by Designation Status
Cervical Simple Fusion
Clinical Risk Factor
Infection
Metastatic cancer and acute leukemia
Cancer
Diabetes and diabetes mellitus complications
Protein-calorie malnutrition
Disorders of fluid/electrolyte/acid-base
Rheumatoid arthritis and inflammatory connective tissue disease
Severe hematological disorders
Dementia and senility
Major psychiatric disorders
Hemiplegia, paraplegia, paralysis, functional disability
Polyneuropathy
Congestive heart failure
Chronic atherosclerosis
Hypertension
Arrhythmias
Stroke
Vascular or circulatory disease
Chronic Obstructive Pulmonary Disease (COPD)
Pneumonia
End-stage renal disease or dialysis
Renal failure
Decubitus ulcer or chronic skin ulcer
Cellulites, local skin infection
Other injuries
Major symptoms, abnormalities
Designated
Hospitals
N=10,065
%
2.2
0.0
2.7
11.3
0.1
3.1
2.1
0.1
0.7
1.8
2.8
1.9
0.9
5.2
36.2
3.6
0.4
3.0
4.4
0.7
0.0
0.7
0.1
0.8
10.5
19.0
a
Other
Hospitals
N=19,710
%
1.9 b
0.0
2.4
11.8
0.1
3.3
2.2
0.1
0.7
1.5
2.6
1.7
0.8
5.2
36.4
3.7
0.3
2.7
4.1
0.6
0.0
0.7
0.2
0.8
10.3
17.4 b
Lumbar Simple Fusion
Designate
d
Other
Hospitals
Hospitals
N=9,212
N=18,477
%
%
2.4
2.2
0.0
0.0
3.0
2.7
12.5
13.1
0.1
0.2 b
7.1
6.2 b
3.8
3.8
0.2
0.1 b
1.2
1.5 b
2.1
1.9
1.7
1.7
1.8
1.9
1.3
1.2
6.5
6.5
42.8
43.4
4.7
4.1 b
0.2
0.2
6.9
5.9 b
4.3
4.7
0.7
0.8
0.0
0.0
1.5
1.4
0.1
0.2
1.1
0.9
7.8
8.1
17.5
16.6
Lumbar
Discectomy/Decompression
Designated
Hospitals
N=11,803
%
1.9
0.0
2.8
11.3
0.1
3.2
2.4
0.1
1.1
1.6
2.1
1.6
1.0
5.7
35.7
3.3
0.2
4.2
2.8
0.5
0.0
0.9
0.2
0.9
8.6
12.6
Other Hospitals
N=17,535
%
1.8
0.1
2.3 b
12.0
0.1
2.9
2.2
0.1
1.3
1.2 b
1.8
1.5
0.9
5.5
37.0 b
3.9 b
0.1
3.8
3.3 b
0.4
0.0
0.8
0.2
0.9
7.9 b
11.8 b
All clinical risk factor categories, except pneumonia, are based on primary and secondary diagnoses from the index stay and from inpatient and outpatient claims data during the
six months preceding the index procedure date. The pneumonia variable is based on primary and secondary diagnoses from inpatient and outpatient claims data during the six
months preceding the index procedure date, not on the index stay.
b
Rates in bold represent a significant difference between designated hospitals and other hospitals based on a chi-square test (P<.05).
27
Table 13. Sensitivity Analysis: Comparison of 90 day Medical Costs (in Dollars) Using a Different Method
Cervical Simple Lumbar Simple
Fusion
Fusion
Lumbar
Disectomy/
Decompression
Percentage Difference between Designated and
Other Hospitals
From Table 5
Total medical costs during 90
3.0% (0.07)
1.8% (0.29)
-0.3% (0.88)
from
days following admission date
Manuscript
Added to risk adjustment - 6
Modifications
month baseline costs in risk
3.2% (0.09)
1.2% (0.59)
0.9% (0.62)
to Model
adjustment*
* Because of concerns that model used in paper might not sufficiently account for differences in baseline risk, we added to the models all costs in the 6 months
prior to the procedure
28
Table 14. Number of Spine Surgeries Performed in Designated Hospitals and Other Hospitals by Type of Surgery Before Exclusions, July 2007September 2009
Designated Hospitals
Type of Spine Surgery
Cervical simple fusion with or
without a discectomy or
decompression
Lumbar simple fusion with or
without a discectomy or
decompression
Lumbar discectomy or
decompression without fusion
Subtotal of spine surgeries
included in analysis
Cervical complex fusion with
or without a discectomy or
decompression
Cervical discectomy or
decompression without fusion
Thoracic/thoracolumbar
simple fusion with or without
a discectomy or
decompression
Thoracic/thoracolumbar
complex fusion with or
without a discectomy or
decompression
Thoracic/thoracolumbar
discectomy or decompression
without fusion
Lumbar complex fusion with
or without a discectomy or
decompression
Total
Included in
Analytic
Sample
N
Included
17,237
25.1
Included
18,737
Included
Other Hospitals
%
N
Unmatched
Hospitals
Total
%
N
25,225
26.5
7,060
25.6
49,522
25.8
27.3
28,253
29.7
8,050
29.2
55,040
28.7
20,976
30.5
27,050
28.4
7,947
28.8
55,973
29.2
Included
56,950
82.8
80,528
84.5
23,057
83.5
160,535
83.8
Not included
3,206
4.7
3,782
4.0
1,038
3.8
8,026
4.2
Not included
2,223
3.2
2,770
2.9
844
3.1
5,837
3.0
Not included
253
0.4
268
8.7
82
0.3
603
0.3
Not included
1,916
2.8
2,317
75.0
915
3.3
5,148
2.7
Not included
441
0.6
505
16.4
164
0.6
1,110
0.6
Not included
3,761
5.5
5,096
5.3
1,502
5.4
10,359
5.4
Included and
not included
68,750
100.0
95,266
100.0
27,602
100.0
191,618
100.0
29
%
N
%
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30