Proximity effects in the electron ionisation mass spectra of substituted cinnamamides.

The electron ionisation mass spectra of an extensive set of 53 ionised monosubstituted and disubstituted cinnamamides [XC6H4CH=CHCONH2, X = H, F, Cl, Br, I, CH3, CH3O, CF3, NO2, CH3CH2, (CH3)2CH and (CH3)3C; and XYC6H3CH=CHCONH2, X = Y = Cl; and X, Y = F, Cl or Br] are reported and discussed. Particular attention is paid to the significance of loss of the substituent, X, from the 2-position, via a rearrangement that is sometimes known as a proximity effect, which has been reported for a range of radical-cations, but is shown in this work to be especially important for ionised cinnamamides. When X is in the 2-position of the aromatic ring, [M - X]+ is formed to a far greater extent than [M - H]+; in contrast, when X is in the 3-position or 4-position, [M - H]+ is generally much more important than [M - X]+. Parallel trends are found in the spectra of XYC6H3CH=CHCONH2: the signal for [M - X]+ dominates that for [M - Y]+ when X is in the 2-position and Y in the 4-position or 5-position, irrespective of the nature of X and Y. Further insight is obtained by studying the competition between expulsion of X· and alternative fragmentations that may be described as simple cleavages. Loss of ·NH2 results in the formation of a substituted cinnamoyl cation, [XC6H4CH=CHCO]+ or [XYC6H3CH=CHCO]+; this process competes far less effectively with the proximity effect when X is in the 2-position than when it is in the 3-position or 4-position. Additional information has been obtained by investigating the competition between formation of [M - H]+ by the proximity effect and loss of CH3· by cleavage of a 4-alkyl group to give a benzylic cation, [R1R2CC6H4CH=CHCONH2]+ (R1, R2 = H, CH3).

First-Time Lumbar Medial Branch Radiofrequency Ablation: Patient-Reported Outcomes Measurement Information System as a Metric of Outcome.

OBJECTIVE: To investigate the ability of Patient-Reported Outcomes Measurement Information System (PROMIS) to capture the therapeutic effect of first-time medial branch radiofrequency ablation (RFA). DESIGN: Before-after trial. SETTING: Single academic spine center. PARTICIPANTS: Patients who underwent first-time medial branch RFA for lumbar facet joint pain identified by dual comparative medial branch block with ≥80% pain relief between January 1, 2015 and September 1, 2019 were identified using procedural billing codes. Charts were reviewed manually to confirm accuracy and strict adherence to the 80% pain relief threshold for each medial branch block. Thirty-nine patients met the criteria and were included in this study (N=39). INTERVENTIONS: Medial branch RFA. MAIN OUTCOME MEASURES: PROMIS score domains of Depression, Pain Interference, and Physical Function collected pre- and post RFA were compared. Pretreatment scores were within 6 weeks prior to the first medial branch block. Posttreatment scores were between 5 weeks and 6 months after RFA. Paired-sample t test analyses were used to calculate responsiveness to treatment, with significance assigned as P<.05 prior to acquiring data. Effect size was calculated using Cohen's d. RESULTS: PROMIS domains of Pain Interference and Physical Function demonstrated a statistically significant improvement (P=.004 and P=.017, respectively). The PROMIS domain of Depression did not demonstrate a statistically significant change (P=.12). The effect size was medium (d=-0.43) for Pain Interference, small/medium (d=0.31) for Physical Function, and small (d=-0.12) for Depression. CONCLUSIONS: Medial branch RFA as a treatment for lumbar facet syndrome is associated with a statistical improvement in PROMIS domains of Physical Function and Pain Interference.

Intraosseous Basivertebral Nerve Radiofrequency Ablation for the Treatment of Vertebral Body Endplate Low Back Pain: Current Evidence and Future Directions.

Recently, basivertebral nerve (BVN) radiofrequency ablation has been developed for the treatment of chronic low back pain (CLBP) thought to arise from the vertebral body endplates (VEPs). This review describes the relevant neuroanatomy and pathobiology of VEP degeneration and injury, imaging correlates of presumed VEP pain, randomized controlled trials performed, appropriate patient selection, and safety. Anatomic, histological, and clinical evidence supports the concept of the VEP as a source of CLBP and the nociceptive role of the BVN. BVN radiofrequency ablation appears to be an effective treatment for a subset of patients with CLBP and evidence of Modic change types 1 and 2 in the L3 to S1 VEPs who have failed to respond to conservative treatment. However, all studies performed to date have been industry sponsored, and future non-industry-funded trials will be needed to confirm these results.

Evaluation of transforaminal epidural steroid injections for discogenic axial lumbosacral back pain utilizing PROMIS as an outcome measure.

BACKGROUND CONTEXT: Discogenic lumbosacral back pain continues to present a challenging clinical entity with limited, controversial therapeutic options. No study to date has evaluated the efficacy of fluoroscopically guided transforaminal epidural steroid injections (TFESI) in a homogenous patient population with axial lumbosacral back pain from discogenic pathology utilizing strict, explicitly clinical and radiographic criteria. Additionally, there is a paucity of published data utilizing Patient Reported Outcome Measurement Information System (PROMIS) scores as an outcome measure for interventional spine procedures. PURPOSE: Evaluate the therapeutic effect of TFESIs in a specific subset of patients with discogenic axial lumbosacral back pain. Investigate PROMIS as an outcome measure for interventional spine procedures targeting focal degenerative spinal pathology. STUDY DESIGN/SETTING: Retrospective review of patients presenting to a multidisciplinary, tertiary academic spine center. PATIENT SAMPLE: Three thousand eight hundred eighty-one patients were screened for inclusion. A total of 26 patients with discogenic axial low back, based on strict clinical and radiographic criteria, underwent TFESIs. All patients had axial low back pain without radicular pain, ≥3 clinical features of discogenic pain, corroborative radiographic features of active discogenic pathology on lumbar spine magnetic resonance imaging without confounding spinal pathology. OUTCOME MEASURES: PROMIS Pain Interference (PI) v1.1, PROMIS Physical Function (PF) v1.2/v2.0, and PROMIS Depression (D) v1.0 outcome scores were collected at baseline and postprocedure follow-up. METHODS: Query of an institutional, patient reported outcome database and subsequent retrospective review of electronic medical records was performed. Statistical analysis comparing baseline and postprocedural PROMIS outcome scores and correlation between these instruments was performed. Additionally, an exploratory investigation of minimal clinically important difference achievement rates was performed. RESULTS: Analysis determined a statistically significant improvement in PROMIS PI (p=.017, 95% CI=-8.02 to -1.82) and PROMIS PF (p=.003, 95% CI=0.91-8.72) scores after treatment with TFESIs. At post treatment time points, TFESI had medium effect size on pain (d=0.55) and function (d=0.59). Change in PROMIS D scores (p=.488, 95% CI -1.74-3.54; d=.08) did not demonstrate statistical significance. Pearson correlation demonstrated a moderate negative correlation (r=-0.544, p=.004) between PROMIS PF with PROMIS PI. Correlation between PROMIS PF (r=-0.239, p=.24) and PROMIS PI (r=0.198, p=.33) with PROMIS D was not significant. Fourteen (53.8%) and 9 (34.6%) subjects achieved minimum clinically important difference (MCID) for PROMIS PI and PROMIS PF, respectively. Nine subjects (34.6%) achieved MCID for PROMIS D despite not otherwise reaching statistical significance otherwise. CONCLUSIONS: Utilizing PROMIS as an outcome measure, discogenic axial lumbosacral back pain patients appear to benefit from TFESI in terms of pain and physical function. This study contributes to the growing body of literature utilizing PROMIS scores in patients with clinical sequelae of degenerative spinal pathology; however, prospective studies are needed.