Research Article Open Access
The Impact of Gender on Post-Operative Length of Stay after Lumbar Decompression Fusion Surgery Referable to Possible Comorbidity Factors
Hollis Floyd1*, Mazen Sanoufa2, Joe Sam Robinson3
1Research assistant, masters in marriage and family therapy
2Research fellow, doctor of medicine
3Neurosurgeon, doctor of medicine
*Corresponding author: Hollis Floyd, Masters in Marriage and Family Therapy, Research assistant at Georgia Neurosurgical Institute, United States.
Received: August 16, 2016; Accepted: September 8, 2016; Published: September 16, 2016
Citation: Floyd H, Sanoufa M, Robinson JS (2016) The Impact of Gender on Post-Operative Length of Stay after Lumbar Decompression Fusion Surgery Referable to Possible Comorbidity Factors. J Rheumatol Arthritic Dis 1(1): 1-4.
Keywords: Costs; Comorbidities; Complications; Gender; Health Care Expenditure; Length of Stay; Lumbar Decompression and Fusion
IntroductionTop
Proportionally more healthcare dollars are devoted to the care of females than their male counterparts (Lassman, Hartman, Washington, Andrews, & Catlin, 2014); rightfully so, as females have a greater life expectancy and a special reproductive burden (Owens, 2008; Vaidya, Gautam, & Karmakar, 2012). In neurosurgery, some controversy exists as to the influence of gender on prolonging hospital stay, particularly following operative intervention for spinal column difficulties (Table 1). To clarify such issues we conducted the following study.
Methods
A retrospective review of the clinical course of all patients that underwent elective lumbar spinal fusion procedures by five neurosurgeons between October 2010 and November 2013 at The Georgia Neurosurgical Institute was undertaken. Comorbidities, complications, and other relevant general variables were obtained. Comorbidities which included twenty four variables relating to preexisting diseases were collected from patients' past medical histories and their preoperative evaluation visit forms (Table 2). Complications were twelve secondary medical problems that developed during hospital stays that were not existent prior to the operation (Table 3). Other collected variables contained age, gender, race, Length of hospital Stay (LOS), Body Mass Index (BMI), and nine others (Table 4). LOS was measured from the day of procedure until the time of discharge (up to the first decimal of a day). As our patient's sample is relatively small in size, we chose to exclude those outliers who stayed more than 4 standard deviations above the mean length of stay (>25.3 days). There were only 4 patients that fell into this category. in LOS. Then, the variables that showed more prevalence in one gender were identified using chi-squared analysis. Finally, each gender cohort was statistically studied separately in order to identify which variables lead to a prolonged LOS in each gender using multivariate linear regression analysis. SPSS-19 software was used to perform all statistics.
Results
A total number of 334 patients were assessed. The mean ±SD
Table 1: Review of articles published in Pub Med since January 2013 about the impact of gender on length of stay in Spine Procedures.

Paper

Year

Study Sample Underwent

Gender related result

Herren et al.17

2014

Posterior lumbar spine fusion procedures

Male gender was a factor prolonged LOS

Schoenfeld et al.18

2013

Spine trauma

Male gender was a predictor for higher mortality and higher complication rate

Alosh et al.19

2015

Anterior cervical spine surgery

Male gender was an independent predictor of hospital charges and LOS

Kelly et al.20

2014

Surgical correction of spondylolisthesis

Female gender was a factor prolonged LOS

Yoshihara et al.21

2014

Surgical treatment of thoracic disc herniation

Female gender was a risk factor for mortality

Sharma et al.22

2014

Spinal cord tumor surgeries

Female gender was an independent predictor of adverse discharge disposition but not to higher costs

Wait et al.23

2013

Cervical or Lumbar spinal fusions

Gender did not show any impact on LOS

length of stay was 5.68±4.9 days. After taking out 4 patients who stayed for more than 25.3 days (4 SDs above the mean LOS), the mean was found to be 5.3±3.4 days. The remaining 330 patients were divided into 190 females and 140 males (see tables 1, 2, and 3 for a detailed description). Females stayed for 1 day longer than males (F=5.7±3.1, M=4.7±3.7; P=0.008).

A history of coronary artery disease was the only variable that showed more prevalence in the male cohort (P=0.041). However, variables that were more prevalent in the female cohort were postoperative anemia severity (P<0.001), vitamin D deficiency (P=0.014), diabetes mellitus (P=.05), hypothyroidism (P=0.005), anxiety disorders (P=0.002), major depressive disorder (P=0.001), obesity (BMI>30, P=0.013), hypotension (P=0.029), severe postoperative respiratory problems (P=0.055), and postoperative psychiatric symptoms (P=0.045).

Variables that showed a significant impact on LOS in the male cohort were postoperative anemia (P=0.033), number of operated levels (P=0.053), developing postoperative infections (P=0.012), postoperative pulmonary embolism (P=0.008), and
Table 2: The Collected Co morbidities.

 

All patients

Males

Females

Preoperative Anemia (Y/N)

30.0%

30.2%

29.4%

Myocardial Infarction

3.7%

4.3%

3.2%

Coronary Artery Disease (other than MI)

11.0%

15.0%

7.9%

Congestive Heart Failure

1.5%

1.4%

1.6%

Arrhythmias

4.8%

5.7%

4.2%

Hypertension

66.1%

63.6%

67.9%

Respiratory Disorders (other than sleep related)

26.2%

23.0%

28.6%

Chronic Obstructive Pulmonary Disease

11.6%

12.2%

11.1%

Sleep Apnea

10.4%

12.9%

8.5%

Chronic Constipation

14.2%

12.9%

15.3%

Peptic Ulcer Disease

2.7%

2.1%

3.2%

Renal Failure

2.1%

1.4%

2.6%

Diabetes Mellitus

30.0%

24.3%

34.2%

Hypothyroidism

18.6%

11.5%

23.8%

Stroke

5.5%

4.3%

6.3%

Transient Ischemic Attach

1.8%

0.7%

2.6%

Seizure

2.1%

0.7%

3.2%

Neuromuscular Disorders

1.8%

1.4%

2.1%

Memory Loss

5.5%

3.6%

6.8%

Anxiety Disorders

20%

12.1%

25.8%

Major Depression

26.1%

16.4%

33.2%

Arthritis

58.8%

61.4%

56.8%

Obesity (BMI≥30)

57.1%

49.3%

63.0%

Morbid Obesity (BMI≥40)

10.6%

10.0%

11.1%

Total Comorbidities

5.8

5.4

6.1

Table 3: The Collected Complication.

 

 

All patients

Males

Females

Postoperative Anemia Severity

No anemia

(≥12 in f. / ≥13.5 in m.)

4.6%

5%

4.3%

Mild Anemia

(<12 in f. / <13.5 in m. to ≥10)

32.3%

51.8%

17.7%

Moderate (<10 to ≥8)

39.1%

32.4%

44.1%

Severe (<8)

24%

10.8%

33.9%

Dural Tear/CSF Leak

 

3.4%

1.4%

4.7%

Fever

 

24.7%

20.3%

22.6%

Infections (total)

 

12.2%

9.4%

14.2%

Urinary Tract Infection

 

3.7%

2.2%

4.7%

Wound Infection

 

2.4%

2.2%

2.6%

Respiratory Complaints

 

7.0%

5.8%

7.9%

Pulmonary Embolism

 

1.2%

2.2%

0.5%

Urinary Retention

 

2.4%

1.4%

3.2%

Postoperative Psychiatric Symptoms

(e.g. hallucination, delirium)

 

3.0%

0.7%

4.7%

Constipation

 

12.5%

9.4%

14.7%

Total Number of Complication

 

2.2

2.1

2.2

postoperative glucose intolerance (P=0.045). However, variables that showed a significant impact on LOS in the female cohort were postoperative anemia severity (P=0.029), developing postoperative urinary retention (P=0.006), postoperative respiratory complications (P=0.006), spinal dural tear (P<0.0001), and neuromuscular disorders (P=0.005).
Discussion
Our study demonstrated that females have more comorbidities than males which might be referable to the different hormonal structures between genders. Our study also recognized that the variables that influence LOS in each gender cohort are different. However, age did not show an independent influence on LOS in either of the genders, despite females being significantly older than males in our study. Recognizing this age disparity, statistical adjustments were accordingly instituted. Following such statistical adjustment, age by itself did change gender's impact on LOS.

Another variable that should be discussed is rehabilitation status. Ireland, Kelly, and Cumming (2015) stated that "referral to hospital-based rehabilitation effectively doubles the total LOS," suggesting that anyone who is subject to rehabilitation after their acute hospital stay will have a longer LOS. This suggests that a patient's post-operative rehabilitation status should be taken into account when determining their LOS. It may be that patients
Table 4: The Collected General Variables.

 

 

All patients

Males

Females

Length of Hospital Stay (Days)

 

5.3

4.7±3.7

5.7±3.1

Gender

 

 

140 (42%)

190 (57%)

Age

 

58.0

56.1 ±13

58.6 ±9.7

>60 years old

48.8%

46.4%

50.5%

 

Race

Caucasians

 

76.4%

64.2%

African American

 

20.7%

34.7%

Type of Insurance

Medicare

 

56.4%

55.8%

Medicaid

 

5.7%

7.9%

Private Insurance

 

26.4%

24.7%

Uninsured

 

5.0%

4.7%

Other

 

5.0%

6.8%

Number of Operated Levels

1

 

47.1%

42.1%

2

 

27.1%

32.6%

3

 

16.4%

15.8%

>3

 

9.3%

9.5%

Body Mass Index (BMI in kg/m2)

 

31.1

30.3

31.6

Anti-Platelet use

 

26.4%

28.3%

25.0%

Drain insertion

 

64.3%

66.7%

62.6%

Cell Saver Use

 

72.9%

68.8%

75.8%

The Need for Blood Transfusion

 

10.5%

7.3%

12.8%

Preoperative Hemoglobin Level

 

13.4

14.3

12.7

Postoperative Hemoglobin Level

 

9.5

10.3

8.9

Vitamin D (ng/mL)

 

27.3

28.9

26.3

Vitamin D < 20

29.1%

19.5%

35.5%

otherwise able to depart a tertiary care facility are shunted into a rehabilitation facility because of inadequate domestic support apparatus. Secondly, in some circumstances, discharge arrangements may have been expedited, preoperatively, so that in some cases those patients going to rehabilitation facilities will leave the hospital sooner than a cohort returning to a home environment.
Implications for Practice and/or Policy
A past history of anxiety disorders and developing postoperative psychiatric symptoms occurred more frequently in females than in males; issues which have been suggested to cause a prolonged hospital LOS (Stundner, et al., 2013; Zatzick, et al., 2000). Moreover, studies consistently assert that chronic pain states are more prevalent in patients with anxiety disorders (Dersh, Polatin, Gatchel, 2000; Lachlan, McWilliams, Cox, 2003; Demyttenaere, Bruffaerts, Lee, 2007) and depressive disorders (Banks, Kerns, 1996; Dersh, Polatin, Gatchel, 2000; Von Korff, et al., 2005; Currie and Wang, 2004). Furthermore, women tend to have more severe pain scores, and perform more poorly on tests of cognitive function postoperatively than men (Heyer, et al., 2000). Also, it was suggested by Korovessis, Pepantis, Papazisis, and Iliopoulos (2010) that males show significantly better improvement in their lower back pain scores than their female counterparts following spine surgery. The psychological, pain, and cognitive burdens that females must face after surgery suggest that females are innately inclined to poorer postoperative outcomes and, thus, an elongated LOS.

In our study cohort females were afflicted with more comorbidites than were males possibly referable to the differing hormonal profile of females that could provide further insight as to why female's have a longer LOS than men. Studies consistently mentioned that estrogen modulates pain sensation via its α and β receptors that spread throughout the central and peripheral nervous systems (Alstergren, Ernberg, Kvarnström, Kopp, 1998; Nomura, et al., 2005; McEwen and Alves, 1999), including the dorsal root ganglia (Papka, et al., 2001), as well as throughout inflammatory cells like monocytes (Phiel, Henderson, Adelman, Elloso, Lett, 2005). The study performed by Craft et al. implicated that estrogen was a stimulant of nociceptive afferents in the peripheral nervous system via different mechanisms (Craft, 2007). Female's inclination to have a higher sensitivity to pain, and their increased tendency to psychiatric distress both could contribute to their elongated LOS.
Conclusion
Understanding the differences in gender for different operative interventions and paying special attention to gender dissimilarities might be useful to decrease postoperative stay and, thus, diminish healthcare expenditure.

We suggest additional inquiry into the impact of comorbidities and complications with particular reference as to why certain comorbidities and complications contribute to prolonging female LOS and not male.
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