Association Between Opioid Use and Patient-Reported Outcomes in a Randomized Trial Evaluating Basivertebral Nerve Ablation for the Relief of Chronic Low Back Pain.

BACKGROUND: Chronic low back pain (CLBP) is a primary indication for opioid therapy. OBJECTIVE: To evaluate the hypothesis that CLBP patients reporting reduced opioid use have superior functional outcomes following basivertebral nerve (BVN) radiofrequency ablation. METHODS: This post hoc analysis from a sham-controlled trial examined short-acting opioid use from baseline through 1 yr. Opioid use was stratified into 3 groups by two blinded external reviewers. Two-sample t-tests were used to compare Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) measurements between those patients who increased or decreased their opioid usage compared to baseline. RESULTS: Actively treated patients with decreased opioid use at 12 mo had a mean ODI improvement of 24.9 ± 16.0 (n = 27) compared to 7.3 ± 9.8 (n = 18) for patients reporting increased opioid use (P < .001). In the sham arm, the improvements in ODI were 17.4 ± 16.1 (n = 19) and 1.2 ± 14.3 (n = 5; P = .053) for the patients reporting decreased vs increased opioid usage, respectively. Actively treated patients reporting decreased opioid use had a mean improvement in VAS of 3.3 ± 2.5 (n = 27) compared to 0.6 ± 1.8 (n = 18) for patients reporting increased opioid use (P < .001). In the sham arm, the improvements in VAS were 2.5 ± 2.6 (n = 19) and 1.4 ± 1.9 (n = 5; P = .374) for patients reporting decreased vs increased opioid use, respectively. CONCLUSION: Subjects undergoing BVN ablation who decreased opioid use had greater improvement in ODI and VAS scores compared with those reporting increased opioid usage. There is an association between functional benefit from BVN ablation and reduced opioid use.

Adjacent segment degeneration following ProDisc-C total disc replacement (TDR) and anterior cervical discectomy and fusion (ACDF): does surgeon bias effect radiographic interpretation?

PURPOSE: Many investigators have reported the financial conflicts of interest (COI), which could result in potential bias in the reporting of outcomes for patients undergoing total disc replacement (TDR) rather than anterior cervical discectomy and fusion (ACDF). This bias may be subconsciously introduced by the investigator in a non-blinded radiographic review. The purpose of this study was to determine if bias was present when a group of spine specialists rated adjacent segment degeneration (ASD) following cervical TDR or ACDF. METHODS: Potential bias in the assessment of ASD was evaluated through the reviews of cervical radiographs (pre- and 6 years post-operative) from patients participating in the ProDisc-C FDA trial (ProDisc-C IDE #G030059). The index level was blinded on all radiographs during the first review, but unblinded in the second. Five reviewers (a radiologist, two non-TDR surgeons, and two TDR surgeons), two of whom had a COI with the ProDisc-C trial sponsor, assessed ASD on a three point scale: yes, no, or unable to assess. Intra- and inter-rater reliabilities between all raters were assessed by the Kappa statistic. RESULTS: The intra-rater reliability between reviews was substantial, indicating little to no bias in assessing ASD development/progression. The Kappa statistics were 0.580 and 0.644 for the TDR surgeons (p < 0.0001), 0.718 and 0.572 for the non-TDR surgeons (p < 0.0001), and 0.642 for the radiologist (p < 0.0001). Inter-rater reliability for the blinded review ranged from 0.316 to 0.607 (p < 0.0001) and from 0.221 to 0.644 (p < 0.0001) for the unblinded review. CONCLUSIONS: The knowledge of the surgical procedure performed did not bias the assessment of ASD.

Deleterious effects of discography radiocontrast solution on human annulus cell in vitro: changes in cell viability, proliferation, and apoptosis in exposed cells.

BACKGROUND CONTEXT: Carragee et al. have recently shown that modern discography injections are associated with subsequent acceleration of disc degeneration, herniation, and loss of disc height. Although needle puncture and pressurization are known trauma events that can create disc degeneration in animal models, another likely culprit in clinical discography-associated degeneration is a direct effect of the contrast agent itself on disc cells. PURPOSE: To test the hypothesis that discography contrast solution would have a deleterious effect on human annulus cells in vitro. STUDY DESIGN: An in vitro study using cultured human annulus cells to assay cell death, cell proliferation, and apoptosis. PATIENT SAMPLE: Annulus cells from eight surgical disc specimens were evaluated (two Thompson Grade III discs and six Grade IV discs) for cell death and proliferation, and an additional five cultures were tested for apoptosis. OUTCOME MEASURES: The proportion of dead and live cells, cell proliferation, and the proportion of apoptotic cells in control and experimental groups. METHODS: After internal review board approval, experimental design used two sets of controls: untreated cells under our normal culture conditions (control) and a set with added glucose to adjust the osmolality to match respective Isovue radiocontrast solution treatments (glucose controls) using a freezing point osmometer. Treated cells received Isovue 200 (iopamidol, Isovue-M 200; Bracco Diagnostics, Inc., Princeton, NJ, USA) at 12.5, 25, 50, or 100 mg/mL. Twenty thousand cells/well were seeded in triplicate in 24 well plates, control or test media added, and incubated for 24 hours. At termination, dead cells were identified with trypan blue staining and percentage dead cells determined. Cells were also tested to determine the percentage of apoptotic cells after 50 or 100 mg/mL Isovue exposures. Proliferation assays used standard plate reader methods. Statistical analysis used repeated measures analysis of variance with SAS software (version 9.2; SAS Institute, Inc., Cary, NC, USA). RESULTS: Analysis of cell death showed a significant increase in the percentage of dead cells with increasing Isovue concentrations compared with control cells (p=.018-.0008). Cell proliferation analyses showed significantly reduced division in Isovue-treated cells (p=.004), and apoptosis assays revealed a significantly higher proportion of apoptotic cells in cells exposed to 50 and 100 mg/mL Isovue (p=.016 and .0003, respectively). CONCLUSIONS: Discography is used extensively in the evaluation of low back pain. Because the lifetime prevalence of disc degeneration and low back pain is high (80% in the general population), many patients may undergo this procedure. Data presented here show that cells exposed in vitro to a radiocontrast agent with adjustments for osmolality have significantly reduced proliferation, increased cell death, and increased programmed cell death (apoptosis). In light of the well-recognized age- and degeneration-related decrease in disc cell numbers, it is possible that radiocontrast exposure may be contributing significantly to disc cell loss with subsequent progression of disc degeneration. Findings presented here provide a plausible cell-based explanation for the previously reported disc degeneration in patients receiving discography contrast solutions.

Oxiplex reduces leg pain, back pain, and associated symptoms after lumbar discectomy.

STUDY DESIGN: Prospective, randomized, blinded clinical trial. OBJECTIVE: To evaluate effectiveness of Oxiplex gel for reduction of pain and associated symptoms after lumbar discectomy. SUMMARY OF BACKGROUND DATA: Oxiplex gel (carboxymethylcellulose, polyethylene oxide, and calcium) is used during discectomy to coat the surgical site for reduction of pain and symptoms after lumbar discectomy. METHODS: Patients undergoing single-level lumbar discectomy performed by laminectomy or laminotomy and randomized to receive either surgery plus Oxiplex gel (treatment group) or surgery alone (control group) were assessed 6 months after surgery using (1) a quality of life questionnaire (Lumbar Spine Outcomes Questionnaire [LSOQ]) and (2) clinical evaluations. RESULTS: There were no statistically significant differences in baseline demographics, surgical procedures, LSOQ scores, and clinical evaluations between treatment (N = 177) and control (N = 175) groups. More gel-treated patients were satisfied with outcome of their surgical treatment than control patients (P = 0.05). The gel-treated group showed greater reductions in pain and symptoms from baseline compared with surgery-only controls. Additional benefits of gel were consistently shown in reduction of leg and back pain at 6 months in the patient population having substantial back pain at baseline (greater than or equal to the median LSOQ pain score of 63). In that population, there was a statistically significant reduction of leg pain and back pain (P < 0.01) in the treatment group compared with controls. Fewer patients in the treatment group had abnormal musculoskeletal physical examinations at 6 months compared with controls. There were no cases of cerebrospinal fluid leaks and no differences in laboratory values or vital signs. Patients in the treatment group had less hypoesthesia, paraesthesia, sensory loss, and fewer reoperations during the 6-month follow-up than controls (1 vs. 6). CONCLUSION: These data demonstrate improvements in clinical outcomes resulting from the use of Oxiplex gel in discectomy procedures for treatment of lumbar disc herniation.

Anatomic mapping and evaluation of the esophagus in relation to the cervical vertebral body.

The relationship of the esophagus to the cervical vertebral body (CVB), disc space and longus colli (LC) muscles, to our knowledge, has not been previously studied. The purpose of this study was to quantify the relationship of the esophagus to the CVB, disc space and LC. 30 patients were selected for a retrospective review of computed tomography (CT) scans. Measurements between the esophagus and the C5, C6, and C7 vertebral bodies as well as the C5/6 and C6/7 disc spaces were performed in the midline, 3 mm right and left of midline, and at the edge of the LC on both sides. The closest distance of the esophagus to the CVB and disc space occurs at the midline (range 1.02-1.31 mm at each level). The furthest distance occurred at the edge of the right LC (range 2.67-3.30 mm at each level). The mean distance from the edge of the right LC to the midline was significantly greater (P < 0.01) than mean distance from the edge of the left LC to the midline. No statistical significant differences were observed when comparing measurements at the individual vertebral bodies and disc spaces. The results of the study demonstrate that the esophagus lies in closest proximity to the CVB and disc space in the midline. A larger potential space exists between the esophagus and the CVB and disc space at the edge of the LC. These results may provide insight into a potential cause of post-operative dysphagia. Furthermore, it may help guide the future design of cervical plates to better utilize the potential space between the esophagus and the CVB and disc space at the edge of the LC.

Adjacent segment disc pressures following two-level cervical disc replacement versus simulated anterior cervical fusion.

Anterior cervical fusion (ACF) has been shown to alter the biomechanics of adjacent segments of the cervical spine. The goal of total disc replacement is to address pathology at a given disc with minimal disruption of the operated or adjacent segments. This study compares the pressure within discs adjacent to either a two-level simulated ACDF or a two-level total disc replacement with the ProDisc-C. A special automated motion testing apparatus was constructed. Four fresh cadaveric cervical spine specimens were affixed to the test stand and tested in flexion and extension under specific loads. Intradiscal, miniature strain-gauge-based transducers were placed in the discs above and below the "treated" levels. The specimens were then tested in flexion and extension. Pressure and overall angular displacement were measured. In the most extreme and highest quality specimen the difference at C3/C4 registered 800 kPa and the difference at C6/C7 registered 50 kPa. This same quality specimen treated with the ProDisc reached a flexion angle at much lower moments, 24.3 degrees at 5 N-m, when compared to the the SACF 12.2 degrees at 8.6 N-m. Therefore, the moment needed to achieve 15 degrees of flexion with the SACF treatment was 5.5 N-m and the ProDisc treatment was only 2.9 N-m. This initial data would indicate that adjacent level discs experience substantially lower pressure after two-level disc replacement when compared to two-level SACF. Additional testing to further support these observations is ongoing.

Upper cervical spine injuries.

The unique anatomy of the upper cervical spine and the typical mechanisms of injury yield a predictable variety of injury patterns. Traumatic ligamentous injuries of the atlanto-occipital joint and transverse atlantal ligament are relatively uncommon, have a poor prognosis for healing, and often respond best to surgical stabilization. Bony injuries, including occipital condyle fractures, atlas fractures, most odontoid fractures, and traumatic spondylolisthesis of the axis, generally respond well to nonsurgical management. Controversy in management remains, however, especially with type II odontoid fractures.