Prediction of 2-year clinical outcome trajectories in patients undergoing anterior cervical discectomy and fusion for spondylotic radiculopathy

OBJECTIVE

Anterior cervical discectomy and fusion (ACDF) is often described as the gold standard surgical technique for cervical spondylotic radiculopathy. Although outcomes are considered favorable, there is little prognostic evidence to guide patient selection for ACDF. This study aimed to 1) describe the 24-month postoperative trajectories of arm pain, neck pain, and pain-related disability; and 2) identify perioperative prognostic factors that predict trajectories representing poor clinical outcomes.

METHODS

In this retrospective cohort study, patients with cervical spondylotic radiculopathy who underwent ACDF at 1 of 12 orthopedic or neurological surgery centers were recruited. Potential outcome predictors included demographic, health, clinical, and surgery-related prognostic factors. Surgical outcomes were classified by trajectories of arm pain intensity, neck pain intensity (numeric pain rating scales), and pain-related disability (Neck Disability Index) from before surgery to 24 months postsurgery. Trajectories of postoperative pain and disability were estimated with latent class growth analysis, and prognostic factors associated with poor outcome trajectory were identified with robust Poisson models.

RESULTS

The authors included data from 352 patients (mean age 50.9 [SD 9.5] years; 43.8% female). The models estimated that 15.5%-23.5% of patients followed a trajectory consistent with a poor clinical outcome. Lower physical and mental health-related quality of life, moderate to severe risk of depression, and longer surgical wait time and procedure time predicted poor postoperative trajectories for all outcomes. Receiving compensation and smoking additionally predicted a poor neck pain outcome. Regular exercise, physiotherapy, and spinal injections before surgery were associated with a lower risk of poor disability outcome. Patients who used daily opioids, those with worse general health, or those who reported predominant neck pain or a history of depression were at greater risk of poor disability outcome.

CONCLUSIONS

Patients who undergo ACDF for cervical spondylotic radiculopathy experience heterogeneous postoperative trajectories of pain and disability, with 15.5%-23.5% of patients experiencing poor outcomes. Demographic, health, clinical, and surgery-related prognostic factors can predict ACDF outcomes. This information may further assist surgeons with patient selection and with setting realistic expectations. Future studies are needed to replicate and validate these findings prior to confident clinical implementation.

Intrathecal Morphine Following Lumbar Fusion: A Randomized, Placebo-Controlled Trial

BACKGROUND

Despite the potential for faster postoperative recovery and the ease of direct intraoperative injection, intrathecal morphine is rarely provided in lumbar spine surgery.

OBJECTIVE

To evaluate the safety and efficacy of intrathecal morphine following lumbar fusion.

METHODS

We randomly assigned 150 patients undergoing elective instrumented lumbar fusion to receive a single intrathecal injection of morphine (0.2 mg) or placebo (normal saline) immediately prior to wound closure. The primary outcome was pain on the visual-analogue scale during the first 24 h after surgery. Secondary outcomes included respiratory depression, treatment-related side effects, postoperative opioid requirements, and length of hospital stay. An intention-to-treat, repeated-measures analysis was used to estimate outcomes according to treatment in the primary analysis.

RESULTS

The baseline characteristics of the 2 groups were similar. Intrathecal morphine reduced pain both at rest (32% area under the curves [AUCs] difference, P < .01) and with movement (22% AUCs difference, P < .02) during the initial 24 h after surgery. The risk of respiratory depression was not increased by intrathecal morphine (hazard ratio, 0.86; 95% confidence interval, 0.44 to 1.68; P = .66). Although postoperative opioid requirements were reduced with intrathecal morphine (P < .03), lengths of hospital stay were similar (P = .32). Other than a trend towards increased intermittent catheterization among patients assigned to intrathecal morphine (P = .09), treatment-related side effects did not significantly differ. The early benefits of intrathecal morphine on postoperative pain were no longer apparent after 48 h.

CONCLUSION

A single intrathecal injection of 0.2 mg of morphine safely reduces postoperative pain following lumbar fusion.

Twelve-month results of a multicenter, blinded, pilot study of a novel peptide (B2A) in promoting lumbar spine fusion

OBJECT

Failure of fusion after a transforaminal lumbar interbody fusion (TLIF) procedure is a challenging problem that can lead to ongoing low-back pain, dependence on pain medication, and inability to return to work. B2A is a synthetic peptide that has proven efficacy in achieving fusion in animal models and may have a better safety profile than bone morphogenetic protein. The authors undertook this study to evaluate the safety and efficacy of B2A peptide-enhanced ceramic granules (Prefix) in comparison with autogenous iliac crest bone graft (ICBG, control) in patients undergoing single-level TLIF.

METHODS

Twenty-four patients with single-level degenerative disorders of the lumbar spine at L2-S1 requiring TLIF were enrolled between 2009 and 2010. They were randomly assigned to 3 groups: a control group (treated with ICBG, n = 9), a Prefix 150 group (treated with Prefix 150 μg/cm(3) granules, n = 8), and a Prefix 750 group (treated with Prefix 750 μg/cm(3) granules, n = 7). Outcome measures included the Oswestry Disability Index (ODI), visual analog pain scale, and radiographic fusion as assessed by CT and dynamic flexion/extension lumbar plain radiographs.

RESULTS

At 12 months after surgery, the radiographic fusion rate was 100% in the Prefix 750 group, 78% in the control group, and 50% in the Prefix 150 group, although the difference was not statistically significant (p = 0.08). At 6 weeks the mean ODI score was 41.0 for the control group, 27.7 for the Prefix 750 group, and 32.2 for the Prefix 150 group, whereas at 12 months the mean ODI was 24.4 for control, 31.1 for Prefix 750, and 29.7 for Prefix 150 groups. Complications were evenly distributed among the groups.

CONCLUSIONS

Prefix appears to provide a safe alternative to autogenous ICBG. Prefix 750 appears to show superior radiographic fusion when compared with autograft at 12 months after TLIF, although no statistically significant difference was demonstrated in this small study. Prefix and control groups both appeared to demonstrate comparable improvements to ODI at 12 months.