Readmission and LOS After Cervical Disc Arthroplasty

In This Article

Abstract and Introduction

Abstract

Study Design: Retrospective cohort study.

Objective: The aim of the study was to assess which factors increase risk of readmission within 30 days of surgery or prolonged length of stay (LOS) (≥2 days) after cervical disc arthroplasty (CDA).

Summary of Background Data: Several studies have shown noninferiority at mid- and long-term outcomes after cervical disc arthroplasty (CDA) compared to anterior cervical discectomy and fusion ACDF, but few have evaluated short-term outcomes regarding risk of readmission or prolonged LOS after surgery.

Methods: Demographics, comorbidities, operative details, postoperative complications, and perioperative outcomes were collected for patients undergoing single level CDA in the National Surgical Quality Improvement Program (NSQIP) database. Patients with prolonged LOS, defined as >2 days, and readmission within 30 days following CDA were identified. Univariable and multivariable logistic regression models were used to identify risk factors for prolonged LOS and readmission.

Results: A total of 3221 patients underwent single level CDA. Average age was 45.6 years (range 19–82) and 53% of patients were male. A total of 472 (14.7%) experienced a prolonged LOS and 36 (1.1%) patients were readmitted within 30 days following surgery. Predictors of readmission were postoperative superficial wound infection (odds ratio [OR] = 73.83, P < 0.001), American Society of Anesthesiologists (ASA) classification (OR = 1.98, P = 0.048), and body mass index (BMI) (OR = 1.06, P = 0.02). Female sex (OR = 1.76, P < 0.001), diabetes (OR = 1.50, P = 0.024), postoperative wound dehiscence (OR = 13.11, P = 0.042), ASA class (OR = 1.43, P < 0.01), and operative time (OR = 1.01, P < 0.001) were significantly associated with prolonged LOS.

Conclusion: From a nationwide database analysis of 3221 patients, wound complications are predictors of both prolonged LOS and readmission. Patient comorbidities, including diabetes, higher ASA classification, female sex, and higher BMI also increased risk of prolonged LOS or readmission.

Level of Evidence: 3

Introduction

Cervical disc arthroplasty (CDA) has emerged as a viable alternative to anterior cervical discectomy and fusion (ACDF) in the treatment of degenerative disc disease. The traditional indications for CDA are patients with one- or two-level stenosis causing radiculopathy or myelopathy that have failed conservative management. Contraindications include, but are not limited to, patients with significant pre-operative instability (>3.5-mm translation on flexion-extension lateral radiographs), axial neck pain, inflammatory arthropathies, severe facet arthropathy, or disc space collapse.^[1] The key advantage of CDA over ACDF is motion preservation, which some studies suggest results in decreased rates of adjacent segment disease, although the literature shows conflicting results in this regard.^[2–5] There are also decreased subjective complaints of dysphagia, earlier return to work, and improved neck disability index and neck pain scores.^[2–4,6,7]

Although the number of disc replacements has rapidly increased in recent years,^[8] little is known regarding the rates and predictors of suboptimal postoperative outcomes, specifically those requiring readmission or prolonged length of stay (LOS). When comparing inpatient and outpatient CDA, a study by Hill et al^[9] suggests that diabetes and higher body mass index (BMI) may be related to need for inpatient status, but the literature is sparse regarding further predictors of outcomes. As such, the purpose of this study was to identify the incidence and specific causes of readmissions and prolonged LOS following inpatient CDA.

Table 1. Patient Demographics and Characteristics
Sex	% (n/total)
Male	53% (1707/3221)
Female	47% (1514/3221)
Race
White	79.5% (2561/3221)
African-American	6.5% (209/3221)
Asian	2.1% (69/3221)
American Indian or Alaska Native	0.46% (15/3221)
Native Hawaiian or Pacific Islander	0.40% (13/3221)
Not reported	11% (354/3221)
ASA Class
ASA 1	11.1% (358/3221)
ASA 2	67.6% (2176/3221)
ASA 3	21% (675/3221)
ASA 4	0.31% (10/3221)

ASA indicates American Society of Anesthesiologists.
*Two patients not reported.

Table 2. Postoperative Complications Requiring Readmission
Complication	n/Total Readmissions (%)
Cervical spine-related complication*	7/36 (19.4%)
Surgical site infection (superficial) or disruption of wound	4/36 (11.1%)
Fall or syncope	3/36 (8.3%)
Dysphagia or localized swelling	2/36 (5.6%)
Headache	2/36 (5.6%)
Surgical site infection (deep)	1/36 (2.8%)
Unplanned intubation	1/36 (2.8%)
Fever	1/36 (2.8%)
Other^†	10/36 (27.8%)
Not reported	5/36 (13.9%)

*Radiculopathy, cervicalgia, fracture of cervical vertebra, displacement of implant, intervertebral disc disorder.
^†Chest pain, abscess unrelated to the cervical spine, contact urticaria, lymphoma complication, conversion disorder, rotator cuff pathology, toxic encephalopathy, major depression, nausea/vomiting, mediastinitis.

Table 3. Variables Resulting in P < 0.1 When Examined for Association With Prolonged LOS and Readmissions
Perioperative Variable	OR (95% CI)	P
Prolonged LOS
Female sex	1.69 (1.38–2.05)	<0.001
Diabetes	2.08 (1.54–2.83)	<0.001
Functional dependence	5.09 (1.7–15.2)	0.006
Hypertension requiring medication	1.54 (1.24–1.91)	<0.001
ASA classification	^	<0.001
Postoperative wound dehiscence	11.7 (1.06–129.2)	0.058
Operative time	1.008 (1.006–1.01)	<0.001
BMI	1.02 (1.001–1.033)	0.039
30-day Readmissions
Diabetes	2.37 (0.98–5.75)	0.059
Postoperative superficial SSI	46.9 (11.2–195.3)	<0.001
ASA classification	^	0.001
BMI	1.07 (1.03–1.12)	<0.001
Operative time	1.006 (1.002–1.01)	0.002

*Risk estimate statistics are only computed for a 2 × 2 table.
ASA indicates American Society of Anesthesiologists; BMI, body mass index; CI, confidence interval; LOS, length of stay; OR, odds ratio; SSI, surgical site infection.

Table 4. Independent predictors of Postoperative Prolonged Length of Stay and Readmission
Perioperative Variable	OR (95% CI)	P
Prolonged LOS
Female sex	1.76 (0.46–0.70)	<0.001
Diabetes	1.50 (1.05–2.13)	0.02
Functional dependence	2.22 (0.64–7.74)	0.21
Hypertension requiring medication	1.11 (0.85–1.44)	0.44
ASA classification	1.43 (1.16–1.76)	0.001
Postoperative wound dehiscence	13.11 (1.10–156.76)	0.04
Operative time	1.008 (1.006–1.009)	<0.001
BMI	0.99 (0.98–1.01)	0.48
30-day Readmissions
Diabetes	0.80 (0.26–2.48)	0.70
Postoperative superficial SSI	73.83 (16.43–331.75)	<0.001
ASA classification	1.98 (1.01–3.89)	0.048
BMI	1.06 (1.01–1.11)	0.02
Operative time	1.00 (0.99–1.01)	0.841
Total LOS	1.03 (0.96–1.10)	0.44

ASA indicates American Society of Anesthesiologists; BMI, body mass index; CI, confidence interval; LOS, length of stay; OR, odds ratio; SSI, surgical site infection.