Huddleston, Paul

Study design. Retrospective observational study of consecutive patients. Objective. The purpose of the study is to determine if a surgeon’s qualitative assessment of bone intraoperatively correlates with radiologic parameters of bone strength. Summary of Background Data. Preoperative radiologic assessment of bone can include modalities such as computed tomography (CT) Hounsfield units (HUs), dual-energy x-ray absorptiometry (DXA) bone mineral density with trabecular bone score (TBS) and magnetic resonance imaging vertebral bone quality (VBQ). Quantitative analysis of bone with screw insertional torque and pull-out strength measurement has been performed in cadaveric models and has been correlated to these radiologic parameters. However, these quantitative measurements are not routinely available for use in surgery. Surgeons anecdotally judge bone strength, but the fidelity of the intraoperative judgment has not been investigated. Methods. All adult patients undergoing instrumented posterior thoracolumbar spine fusion by one of seven surgeons at a single center over a 3-month period were included. Surgeons evaluated the strength of bone based on intraoperative feedback and graded each patient’s bone on a 5-point Likert scale. Two independent reviewers measured preoperative CT HUs and magnetic resonance imaging VBQ. Bone mineral density, lowest T-score, and TBS were extracted from DXA within 2 years of surgery. Results. Eighty-nine patients were enrolled and 16, 28, 31, 13, and 1 patients had Likert grade 1 (strongest bone), 2, 3, 4, and 5 (weakest bone), respectively. The surgeon assessment of bone correlated with VBQ (τ=0.15, P=0.07), CT HU (τ=−0.31, P<0.01), lowest DXA T-score (τ=−0.47, P<0.01), and TBS (τ=−0.23, P=0.06). Conclusion. Spine surgeons’ qualitative intraoperative assessment of bone correlates with preoperative radiologic parameters, particularly in posterior thoracolumbar surgeries. This information is valuable to surgeons as this supports the idea that decisions based on feel in surgery have a statistical foundation.

Study Design. Retrospective matched cohort study. Objective. To determine if low-pressure lumbar provocation discography (PD) results in long-term accelerated disc degeneration, internal disc disruption, or disc herniation in patients with symptomatic low back pain (LBP). Summary of Background Data. Study of subjects without clinically-significant LBP suggests that high-pressure PD may accelerate disc degeneration. Methods. Consecutive patients with symptomatic LBP who underwent magnetic resonance imaging (MRI), PD, and repeat MRI more than 7 years later, but did not undergo subsequent spinal fusion surgery, were included. Punctured discs were matched (1:2 to 1:4) to corresponding discs in a control cohort by age, BMI, Pfirrmann score (±2), and presence of disc herniation; control cohort inclusion required MRIs for symptomatic LBP, separated by more than 7 years. The primary outcome of the study was a progression in Pfirrmann score category (I–II, III–IV, V). MRI disc-to-CSF T2 signal-intensity ratio, disc height, disc herniations, high intensity zones (HIZs), and Modic changes were assessed. Results. Baseline and follow-up MRIs were available for 77 discs exposed to PD, and for 260 discs in the matched control cohort. There was no difference in the proportion of punctured discs that advanced in Pfirrmann score category in the PD group (17%, 95% CI 9–27%) compared with corresponding discs in the Control group (21%, 95% CI 17–27%), P = 0.3578, or in non-punctured discs in the PD group (35%, 95% CI 21–51%) compared with corresponding discs in the Control group (34%, 95% CI 27–42%), P = 0.1169. There were no differences in disc-to-CSF T2 signal-intensity ratio, presence of disc herniations, HIZs, or Modic changes following puncture in the PD versus matched cohort discs or in the non-punctured PD cohort discs versus corresponding control cohort discs (P > 0.05). Conclusion. Patients with symptomatic LBP who underwent low-pressure PD, but who did not undergo a subsequent spinal fusion surgery, developed disc degeneration and new disc herniations at a similar rate to corresponding discs in matched control patients. Level of Evidence: 3

Study Design: This is a prospective cohort study. Objective: To characterize the accuracy of patient recollection of preoperative symptoms after cervical spine surgery. Summary of Background Data: Recall bias is a well-known source of systematic error. The accuracy of patient recall after cervical spine surgery remains unknown. Methods: Consecutive patients undergoing cervical spine surgery for myelopathy or radiculopathy were enrolled. Neck and arm numeric pain scores and Neck Disability Indices were recorded preoperatively. Patients were asked to recall their preoperative status at either short (<1 y) or long-term (≥1 y) follow-up. Actual and recalled scores were compared using paired t tests and relations were quantified using the Pearson correlation coefficients. Multivariable linear regression was used to identify factors impacting recollection. Results: In total, 73 patients with a mean age of 58.2 years were included. Compared with their preoperative scores, patients showed significant improvement in neck pain [mean difference (MD)=−2.9; 95% confidence intervals (CIs), −3.5 to −2.3], arm pain (MD, −3.4; 95% CI, −4.0 to −2.8), and disability (MD, −12.4%; 95% CI, −16.9 to −7.9). Patient recollection of preoperative status was significantly more severe than actual for neck pain (MD, +1.5; 95% CI, 0.8–2.2), arm pain (MD, +2.3; 95% CI, 1.6–3.0), and disability (MD, +5.8%; 95% CI, 2.4–9.2). Moderate correlation between actual and recalled scores with regard to neck (r=0.41), arm (r=0.50) pain, and disability (r=0.67) was seen. This was maintained across age, sex, and time between date of surgery and recollection. Over 30% of patients switched their predominant symptom from neck-to-arm pain or vice versa on recall of their preoperative symptoms. Conclusions: Relying on patient recollection does not provide an accurate measure of preoperative status after cervical spine surgery. Prospective and not retrospective collection of patient-reported outcomes remain the gold standard to measure and interpret outcomes after cervical spine surgery. Recall bias has the potential to affect patient satisfaction and requires further study.

ABSTRACTDegenerative disk disease of the spine is a major cause of back pain and disability. Optimization of regenerative medical therapies for degenerative disk disease requires a deep mechanistic understanding of the factors controlling the structural integrity of spinal tissues. In this investigation, we sought to identify candidate regulatory genes controlling extracellular matrix synthesis in spinal tissues. To achieve this goal we performed high throughput next generation RNA sequencing on 39 annulus fibrosus and 21 nucleus pulposus human tissue samples. Specimens were collected from patients undergoing surgical discectomy for the treatment of degenerative disk disease. Our studies identified associations between extracellular matrix genes, growth factors, and other important regulatory molecules. The fibrous matrix characteristic of annulus fibrosus was associated with expression of the growth factors platelet derived growth factor beta (PDGFB), vascular endothelial growth factor C (VEGFC), and fibroblast growth factor 9 (FGF9). Additionally we observed high expression of multiple signaling proteins involved in the NOTCH and WNT signaling cascades. Nucleus pulposus extracellular matrix related genes were associated with the expression of numerous diffusible growth factors largely associated with the transforming growth signaling cascade, including transforming factor alpha (TGFA), inhibin alpha (INHA), inhibin beta A (INHBA), bone morphogenetic proteins (BMP2, BMP6), and others. Clinical significance: this investigation provides important data on extracellular matrix gene regulatory networks in disk tissues. This information can be used to optimize pharmacologic, stem cell, and tissue engineering strategies for regeneration of the intervertebral disk and the treatment of back pain. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1356–1369, 2018.