Early Morbidity of Multilevel Anterior Cervical Discectomy and Fusion with Plating for Spondylosis: Does the Number of Levels Influence Early Complications? A Single Surgeon's Experience in 519 Consecutive Patients

Abstract

Study Design This is a retrospective review of a prospectively maintained database of anterior cervical discectomy and fusion with plating (ACDFP) cases.

Objective The aim of this study is to evaluate within a clinical practice evidence-based results of short-term morbidity with multilevel ACDFP.

Methods Clinical morbidity, length of hospital stay, visual analog scale (VAS) and Odom scores, Neck Disability Index (NDI), hardware failure, and return-to-work (RTW) status were prospectively collected in an electronic database for 678 patients who underwent 1-, 2-, 3-, or 4-level ACDFP during an 8-year period. A total of 519 patients met the study criteria and were retrospectively analyzed.

Results The majority of all patients noted “Excellent” or “Good” status for 1 month (91%), 2 months (92%), and 3 months (96%). Patients with 1-, 2-, and 3-level ACDFP returned to work sooner, 60% at 1 month, 70% at 2 months, and 68% at 3 months. For 4-level patients, the majority did not RTW until 3 months (71%). The only significant increase in morbidity with increasing levels was hospital stay for 3- and 4-level ACDFP and RTW for 4-level ACDFP.

Conclusion Multilevel ACDFP can be performed with low initial morbidity. An individual practice can review results to allow for ongoing evidence-based care.

Final class of evidence - treatment	Yes
Study design
RCT
Cohort	•
Case control
Case series
Methods
Concealed allocation (RCT)
Intention to treat (RCT)
Blinded/independent evaluation of primary outcome	•
F/U ≥ 85%
Adequate sample size	•
Control for confounding
Overall class of evidence	III

Keywords

ACDFP - cervical spine - morbidity

Study Rationale and Context

There are theoretical advantages to approaching multilevel diseased cervical segments anteriorly with a single ACDFP rather than performing anterior–posterior or multiple setting surgeries. However, no large or homogeneous studies exist to support or refute whether multilevel anterior cervical discectomy and fusion with plating (ACDFP) carries an unacceptably greater initial morbidity.

Objective

Early morbidity as measured by perioperative complications, hospital stay, pain assessments, hardware failure, and RTW status was evaluated for 1-, 2-, 3-, and 4-level ACDFP during the first 3 months after surgery.

Methods

Study Design: Retrospective case series.

Inclusion Criteria: Patients who underwent 1-, 2-, 3-, or 4-level ACDFP by one surgeon at a single university–affiliated hospital using the modified Smith–Robinson[1] technique. Patients reflected the specific population seen by the senior author (D.E.B.); these were elective procedures done in relatively healthy individuals (see online supplementary material).

Exclusion Criteria: Patients were excluded for traumatic injuries, revision surgery, or if the patients had certain comorbidities that were known to increase the surgical morbidity: chronic steroid use, chronic dialysis, rheumatoid arthritis, and so on. For the subjective follow-up and return-to-work (RTW) portion of the study, workers' compensation and litigation patients were excluded.

Patient Population: A total of 678 patients underwent ACDFP between May 2001 and December 2009. Of these, 519 met study criteria and were retrospectively reviewed for the initial 3-month postoperative period ([Fig. 1]).

Fig. 1 Patient sampling and selection.

Intervention:

• Discectomy was always performed utilizing the surgical microscope from the patient's right side.

• Standard constructs were employed: structural allografts or cages filled with biologic material with anterior plating. Esophageal catheters were not allowed during surgery and the endotracheal cuff was routinely deflated for 90 seconds at the time of the initial placement of the retractors.

• Patients were generally admitted for 23-hour observation and were given 10 mg dexamethasone and an antibiotic, generally 1 g of Ancef (GlaxoSmithKline, Research Triangle Park, NC, USA), prior to induction and two additional times over the next 18 hours.

• All patients wore hard collars while riding in cars; they were weaned from their collars at 2 weeks.

Outcomes:

• Length of hospital stay and rate of complications were recorded and evaluated.

• At 1-, 2-, and 3-month follow-ups, patients had detailed clinical examinations and were assessed using the Odom scale; lateral X-rays in flexion, neutral, and extension; VAS scores for neck, hand, arm, and shoulder; Neck Disability Index (NDI); and RTW status.

• The radiographs were reviewed by the senior author, three clinicians, a radiologist, and by a second independent neuroradiologist if needed for hardware failure or structural problems.

Analysis: Statistical analysis was conducted by Synthes Research and by a second independently contracted statistician, using a generalized version of Fisher exact test for an R × C contingency table to generate the p values.

Results

• Patient Characteristics: Mean age for patients was as follows: 45, 49, 52, and 53 years for 1-, 2-, 3-, and 4-level ACDFP, respectively. For gender, 45% were male ([Table 1]).

• Complications: The most common complication across all four ACDFP levels was swallowing/speech dysfunction (n = 10), followed by uncontrolled pain (n = 3), then hematoma and reoperation (n = 2). There were no reported infections, hospital readmissions, or instances of hardware failure.

• Hospital Stay: Patients who underwent 3- or 4-level ACDFP had a significant difference in length of stay (p = < 0.0001 for both levels), but this generally represented one additional night for 3-level ACDFP and one or two nights for 4-level ACDFP.

• Odoms, VAS, NDI: There was no statistically significant clinical difference among the results with relationship to number of levels surgically treated ([Fig. 2]).

• Return to Work: There was no statistical difference between 1-, 2-, and 3-levels for 1, 2, and 3 months. The 4-level patients had a significant difference from 1- and 2-levels at all time points (p = 0.0029 for 1 month, p = 0.003 for 2 months, and p = 0.015 for 3 months).

Fig. 2 Line graphs showing similar trends in Neck Disability Index (NDI) (a, b), visual analog scale (VAS) scores (c), and Odom scores (d). Odom scores are rated as 1 for Excellent, 2 for Good, 3 for Fair, and 4 for Poor.

Table 1 Patient characteristics

	No. (%)
	1 and 2 levels (n = 251)	3 and 4 levels (n = 268)
Demographics (N = 519 patients)
Male	100 (39.8)	133 (49.6)
Mean age (range)	48.2 (16–78)	52.6 (31–75)
Type of comorbidity
Smoking	33 (13.1)	50 (18.7)
Hypertension	31 (12.4)	68 (25.4)
Obese	24 (9.6)	26 (9.7)
IDDM	4 (1.6)	6 (2.2)
NIDDM	10 (4.0)	12 (4.5)

Abbreviations: IDDM, insulin-dependent diabetes mellitus; NIDDM, non–insulin-dependent diabetes mellitus.

Discussion

• One of the criticisms of multilevel ACDFP is that there is a significant increase in perioperative morbidity. However, the reports in the general literature are highly variable.[2] [3] [4] [5] [6] [7] [8] [9] A recent article used a meta-analysis of published literature for the surgical treatment of cervical disease during the period from 1990 to 2005. Unfortunately, the limitations of the study prevented the application of their findings to general practice of multilevel disease because of the relatively small size of the studies reviewed and the heterogeneity of the techniques employed.[10] [11]

• To address these issues, we have prospectively collected and retrospectively evaluated clinical data and utilized a consistent surgical approach in a large number of patients. To our knowledge, our patient database is the largest group reported on in the literature.

• We recognize that this is a selected patient population and that these results cannot be applied to trauma or other high-risk populations.

• Our study shows that multilevel ACDFP can be performed with minimal initial morbidity in a group of generally healthy patients. We also believe that this study shows that an individual's clinical practice can be driven by careful data collection.

Summary and Conclusion

Our results show that multilevel ACDFP can be done without significantly higher morbidity rates and that a practice can evaluate its results to adjust treatment recommendations accordingly. We saw transient increases in dysfunction in 3- and 4-level ACDFP, but none of the increases were statistically significant other than for hospital stay for 3- and 4-level ACDFP and RTW for 4-level ACDFP.

Financial Support

The authors received grant support from the Synthes Research Foundation for the development and maintenance of the database used in this study.

Previous Presentations of Paper

A portion of this work was presented as an electronic poster at the 2010 American Association of Neurological Surgeons meeting in Philadelphia, PA, and as an invited talk at the North Carolina Spine Society meeting in Charlotte, North Carolina, August 27 to 28, 2010.

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• References Editorial Perspective

• 1 Bazaz R, Lee MJ, Yoo JU. Incidence of dysphagia after anterior cervical spine surgery: a prospective study. Spine 2002; 27 (22) 2453-2458