Mice lacking substance P have normal bone modeling but diminished bone formation, increased resorption, and accelerated osteopenia with aging.

Substance P (SP) is a sensory neuropeptide that is expressed by the neurons innervating bone. There is considerable evidence that SP can regulate bone cell function in vitro, but it is unclear whether SP modulates bone modeling or remodeling in vivo. To answer this question we characterized the bone phenotype of mice with deletion of the Tac1 gene expressing SP. The phenotypes of 2-month-old and 5-month-old SP deficient mice and their wildtype controls were characterized by using µCT imaging, static and dynamic bone histomorphometry, and urinary deoxypyridinoline cross-links (DPD) measurement. No differences in bone phenotypes were observed between the 2 strains at 2 months of age. By 5 months both the wildtype and SP deficient mice had developed cancellous osteopenia, but relative to the wild-type mice the SP deficient mice had significantly greater cancellous bone loss. The SP deficient mice also exhibited decreased bone formation, increased osteoclast number, and increased urinary DPD levels. Cortical defect early repair was delayed in 5-month-old mice lacking SP. Collectively, these findings indicate that SP signaling is not required for bone modeling, but SP signaling reduces age-related osteopenia and accelerates cortical defect reparation, data supporting the hypothesis that SP is an anabolic physiologic regulator of bone metabolism.

Efficacy of Superior Hypogastric Plexus Neurolysis for the Treatment of Cancer-Related Pelvic Pain.

OBJECTIVE: Cancer-related abdominal and pelvic pain syndromes can be debilitating and difficult to treat. The objective of this study was to evaluate the efficacy of superior hypogastric plexus blockade or neurolysis (SHPN) for the treatment of cancer-related pelvic pain. DESIGN: Retrospective study. SETTING: MD Anderson Cancer Center, Houston, Texas. METHODS: We enrolled 46 patients with cancer-related pelvic pain who underwent SHPN. A numeric rating scale (NRS) was used for pain intensity, and symptom burden was evaluated using the Edmonton Symptom Assessment System at baseline, visit 1 (within one month), and visit 2 (within one to six months). RESULTS: Forty-six patients who received SHPN showed a significant reduction in pain score from 6.9 to 5.6 at visit 1 (P = 0.01). Thirty of the 46 patients continued to complete visit 2 follow-up, and the NRS score was consistently lower at 4.5 at visit 2 (P < 0.0001), with anxiety and appetite improved significantly. There was no significant change in the morphine equivalent dose at visits 1 and 2. The efficacy of the block was not influenced by patients' age, gender, type of cancer, cancer stage, regimen of chemotherapy and/or radiation therapy, diagnostic block, approach or laterality of procedure, or type or amount of neurolytic agent. Nonsmokers with high baseline pain scores were more likely to have improved treatment outcomes from SHPN at short-term follow-up. Adverse effects with SHPN were mild and well tolerated. CONCLUSIONS: SHPN was an effective and relatively safe procedure for pain associated with pelvic malignancies. There is a need for larger prospective trials.

Treatment of Chemotherapy-Induced Peripheral Neuropathy: Systematic Review and Recommendations.

BACKGROUND: Chemotherapy-induced peripheral neuropathy (CIPN) is a commonly encountered disease entity following chemotherapy for cancer treatment. Although only duloxetine is recommended by the American Society of Clinical Oncology (ASCO) for the treatment of CIPN in 2014, the evidence of the clinical outcome for new pharmaceutic therapies and non-pharmaceutic treatments has not been clearly determined. OBJECTIVE: To provide a comprehensive review and evidence-based recommendations on the treatment of CIPN. STUDY DESIGN: A systematic review of each treatment regimen in patients with CIPN. METHODS: The literature on the treatment of CIPN published from 1990 to 2017 was searched and reviewed. The 2011 American Academy of Neurology Clinical Practice Guidelines Process Manual was used to grade the evidence and risk of bias. We reviewed and updated the recommendations of the ASCO in 2014, and evaluated new approaches for treating CIPN. RESULTS: A total of 26 treatment options in 35 studies were identified. Among these, 7 successful RCTs, 6 failed RCTs, 18 prospective studies, and 4 retrospective studies were included. The included studies examined not only pharmacologic therapy but also other modalities, including laser therapy, scrambler therapy, magnetic field therapy and acupuncture, etc. Most of the included studies had small sample sizes, and short follow-up periods. Primary outcome measures were highly variable across the included studies. No studies were prematurely closed owing to its adverse effects. LIMITATIONS: The limitations of this systematic review included relatively poor homogeneous, with variations in timing of treatment, primary outcomes, and chemotherapeutic agents used. CONCLUSION: The evidence is considered of moderate benefit for duloxetine. Photobiomodulation, known as low level laser therapy, is considered of moderate benefit based on the evidence review. Evidence did not support the use of lamotrigine and topical KA (4% ketamine and 2% amitriptyline). The evidence for tricyclic antidepressants was inconclusive as amitriptyline showed no benefit but nortriptyline had insufficient evidence. Further research on CIPN treatment is needed with larger sample sizes, long-term follow-up, standardized outcome measurements, and standardized treatment timing. KEY WORDS: Chemotherapy-induced neuropathy, peripheral neuropathy, chemotherapy-tumor, neuropathic pain, chronic pain, toxicology, treatment, reduction of pain, level of evidence.

An updated understanding of the mechanisms involved in chemotherapy-induced neuropathy.

The burdensome condition of chemotherapy-induced peripheral neuropathy occurs with various chemotherapeutics, including bortezomib, oxaliplatin, paclitaxel and vincristine. The symptoms, which include pain, numbness, tingling and loss of motor function, can result in therapy titrations that compromise therapy efficacy. Understanding the mechanisms of chemotherapy-induced peripheral neuropathy is therefore essential, yet incompletely understood. The literature presented here will address a multitude of molecular and cellular mechanisms, beginning with the most well-understood cellular and molecular-level changes. These modifications include alterations in voltage-gated ion channels, neurochemical transmission, organelle function and intracellular pathways. System-level alterations, including changes to glial cells and cytokine activation are also explored. Finally, we present research on the current understanding of genetic contributions to this condition. Suggestions for future research are provided.

Ultrasonographic Validation of Anatomical Landmarks for Localization of the Tendon of the Long Head of Biceps Brachii.

Objectives. To establish anatomical landmarks for biceps tendon groove localization based on intrinsic anatomical relations and to validate the localization with ultrasonographic measurement. Design. Perspective, observational, single-blinded pilot study. Participants. 25 healthy male and female volunteers ages 24-50 years. Methods. We used two anatomical landmarks, the medial epicondyle vertical line related landmark and the coracoid process landmark. The distance from the groove skin mark to the medial epicondyle vertical line and the coracoid process was measured horizontally and was measured at 0° and 45° of shoulder external rotation, respectively. Results. Medial epicondyle vertical lines were 9.3 mm/21.5 mm medial to the groove at 0°/45° of shoulder external rotation, respectively. Correlation coefficients were 0.04/0.10, 0.32/0.42, and 0.26/0.37 for weight, height, and BMI in 0°/45° of shoulder external rotation, respectively. The distance between the coracoid process and the groove was 44.0 mm/62.2 mm in 0°/45° of shoulder external rotation, respectively. Correlation coefficients were 0.36/0.41, 0.36/0.54, and 0.18/0.12 for weight, height, and BMI in 0°/45° of shoulder external rotation, respectively. Conclusions. The medial epicondyle vertical line and the coracoid process landmark are both useful anatomical landmarks to localize the biceps groove. The anatomical landmark based localization is essentially not correlated with subject's weight, height, or BMI.

Bisphosphonates Inhibit Pain, Bone Loss, and Inflammation in a Rat Tibia Fracture Model of Complex Regional Pain Syndrome.

BACKGROUND: Bisphosphonates are used to prevent the bone loss and fractures associated with osteoporosis, bone metastases, multiple myeloma, and osteogenesis deformans. Distal limb fractures cause regional bone loss with cutaneous inflammation and pain in the injured limb that can develop into complex regional pain syndrome (CRPS). Clinical trials have reported that antiresorptive bisphosphonates can prevent fracture-induced bone loss, inhibit serum inflammatory cytokine levels, and alleviate CRPS pain. Previously, we observed that the inhibition of inflammatory cytokines or adaptive immune responses attenuated the development of pain behavior in a rat fracture model of CRPS, and we hypothesized that bisphosphonates could prevent pain behavior, trabecular bone loss, postfracture cutaneous cytokine upregulation, and adaptive immune responses in this CRPS model. METHODS: Rats underwent tibia fracture and cast immobilization for 4 weeks and were chronically administered either subcutaneously perfused alendronate or oral zoledronate. Behavioral measurements included hindpaw von Frey allodynia, unweighting, warmth, and edema. Bone microarchitecture was measured by microcomputed tomography, and bone cellular activity was evaluated by static and dynamic histomorphometry. Spinal cord Fos immunostaining was performed, and skin cytokine (tumor necrosis factor, interleukin [IL]-1, IL-6) and nerve growth factor (NGF) levels were determined by enzyme immunoassay. Skin and sciatic nerve immunoglobulin levels were determined by enzyme immunoassay. RESULTS: Rats with tibia fractures developed hindpaw allodynia, unweighting, warmth, and edema, increased spinal Fos expression and trabecular bone loss in the lumbar vertebra and bilateral distal femurs as measured by microcomputed tomography, increased trabecular bone resorption and osteoclast surface with decreased bone formation rates, increased cutaneous inflammatory cytokine and NGF expression, and elevated immunocomplex deposition in skin and nerve. Alendronate (60 µg/kg/d subcutaneously [s.c.]) or zoledronate (3 mg/kg/d orally) treatment for 28 days, started at the time of fracture, completely inhibited the development of hindpaw allodynia and reduced hindpaw unweighting by 44% ± 13% and 58% ± 5%, respectively. Orally administered zoledronate (3 mg/kg/d for 21 days) treatment also completely reversed established allodynia and unweighting when started at 4 weeks postfracture. Histomorphometric and microcomputed tomography analysis demonstrated that both the 3 and 60 µg/kg/d alendronate treatments reversed trabecular bone loss (an 88% ± 25% and 188% ± 39% increase in the ipsilateral distal femur BV/TV, respectively) and blocked the increase in osteoclast numbers and erosion surface observed in bilateral distal femurs and in L5 vertebra of the fracture rats. Alendronate treatment inhibited fracture-induced increases in hindpaw inflammatory mediators, reducing postfracture levels of tumor necrosis factor by 43% ± 9%, IL-1 by 60% ± 9%, IL-6 by 56% ± 14%, and NGF by 37% ± 14%, but had no effect on increased spinal cord Fos expression, or skin and sciatic nerve immunocomplex deposition. CONCLUSIONS: Collectively, these results indicate that bisphosphonate therapy inhibits pain, osteoclast activation, trabecular bone loss, and cutaneous inflammation in the rat fracture model of CRPS, data supporting the hypothesis that bisphosphonate therapy can provide effective multimodal treatment for CRPS.

A Systematic Evaluation of Burst Spinal Cord Stimulation for Chronic Back and Limb Pain.

BACKGROUND: Traditional tonic spinal cord stimulation (SCS) has been approved by FDA for chronic pain of intractable back and limb pain. However, it induces paresthesia and relieves pain poorly to some extent. Recently, burst SCS has been developed for pain reduction without the mandatory paresthesia. STUDY DESIGN: A systematic review of burst SCS for chronic back and limb pain. OBJECTIVE: The objective of this systematic review is to determine the effects of burst SCS on pain relief without paresthesia for various conditions including failed back surgery syndrome, painful diabetic neuropathy, and radiculopathy. METHODS: The available literature on burst SCS in managing chronic pain without paresthesia was reviewed. The 2011 American Academy of Neurology (AAN) Classification of Evidence Guidelines Process Manual was used to grade the evidence and risk of bias. Data sources included relevant literature identified through searches of PubMed, MEDLINE/OVID, SCOPUS, and manual searches of the bibliographies of known primary and review articles. OUTCOME MEASURES: The primary outcome measure was pain relief and paresthesia status. Secondary outcome measures were improvement in pain quality, functional status, and complications. RESULTS: For this review, five studies including a total of 117 patients met the eligibility criteria. All studies were graded a Class IV study. LIMITATIONS: The limitations of this systematic review include an overall paucity of high quality studies. CONCLUSION: Burst SCS is a new approach that possibly causes more pain reduction for short-term duration than tonic SCS without eliciting paresthesia. The evidence based on this systematic review for burst SCS in treating chronic intractable pain is considered fair and limited. This is an AAN recommendation level U. Further research is needed with a larger sample size and a standardized study design.

Botulinum Toxin Injection for Spastic Scapular Dyskinesia After Stroke: Case Series.

Spastic scapular dyskinesia after stroke is rare, which causes impaired shoulder active range of motion (ROM). To date, there has been no report about botulinum toxin injection to spastic periscapular muscles. This study presents botulinum toxin A injection for management of spastic periscapular muscles after stroke in 2 cases.This is a retrospective study of 2 cases of spastic scapular dyskinesia after stroke. Spasticity of periscapular muscles including rhomboid and lower trapezius was diagnosed by physical examination and needle electromyographic study. Botulinum toxin was injected into the spastic periscapular muscles under ultrasound imaging guidance.During the 3-week follow-up visit after injection, both patients showed increased shoulder active ROM, without any sign of scapular destabilization.The results suggest that botulinum toxin injection to spastic periscapular muscles can increase shoulder active ROM without causing scapular destabilization in patients with poststroke spastic scapular dyskinesia.

Neuropeptide deficient mice have attenuated nociceptive, vascular, and inflammatory changes in a tibia fracture model of complex regional pain syndrome.

BACKGROUND: Distal limb fracture in man can induce a complex regional pain syndrome (CRPS) with pain, warmth, edema, and cutaneous inflammation. In the present study substance P (SP, Tac1(-/-)) and CGRP receptor (RAMP1(-/-)) deficient mice were used to investigate the contribution of neuropeptide signaling to CRPS-like changes in a tibia fracture mouse model. Wildtype, Tac1(-/-), and RAMP1(-/-) mice underwent tibia fracture and casting for 3 weeks, then the cast was removed and hindpaw mechanical allodynia, unweighting, warmth, and edema were tested over time. Hindpaw skin was collected at 3 weeks post-fracture for immunoassay and femurs were collected for micro-CT analysis. RESULTS: Wildtype mice developed hindpaw allodynia, unweighting, warmth, and edema at 3 weeks post-fracture, but in the Tac1(-/-) fracture mice allodynia and unweighting were attenuated and there was no warmth and edema. RAMP1(-/-) fracture mice had a similar presentation, except there was no reduction in hindpaw edema. Hindpaw skin TNFα, IL-1ß, IL-6 and NGF levels were up-regulated in wildtype fracture mice at 3 weeks post-fracture, but in the Tac1(-/-) and RAMP1(-/-) fracture mice only IL-6 was increased. The epidermal keratinocytes were the cellular source for these inflammatory mediators. An IL-6 receptor antagonist partially reversed post-fracture pain behaviors in wildtype mice. CONCLUSIONS: In conclusion, both SP and CGRP are critical neuropeptide mediators for the pain behaviors, vascular abnormalities, and up-regulated innate immune responses observed in the fracture hindlimb. We postulate that the residual pain behaviors observed in the Tac1(-/-) and RAMP1(-/-) fracture mice are attributable to the increased IL-6 levels observed in the hindpaw skin after fracture.

Keratinocyte expression of inflammatory mediators plays a crucial role in substance P-induced acute and chronic pain.

Tibia fracture in rats followed by cast immobilization leads to nociceptive, trophic, vascular and bone-related changes similar to those seen in Complex Regional Pain Syndrome (CRPS). Substance P (SP) mediated neurogenic inflammation may be responsible for some of the signs of CRPS in humans. We therefore hypothesized that SP acting through the SP receptor (NK1) leads to the CRPS-like changes found in the rat model. In the present study, we intradermally injected rats with SP and monitored hindpaw mechanical allodynia, temperature, and thickness as well as tissue levels of tumor necrosis factor-α (TNF-α), interleukin 1ß (IL-1ß), interleukin 6 (IL-6), and nerve growth factor-ß (NGF) for 72 h. Anti-NGF antibody was utilized to block the effects of SP-induced NGF up-regulation. Fracture rats treated with the selective NK1 receptor antagonist LY303870 prior to cast removal were assessed for BrdU, a DNA synthesis marker, incorporation in skin cells to examine cellular proliferation. Bone microarchitecture was measured using micro computed tomography (µCT). We observed that: (1) SP intraplantar injection induced mechanical allodynia, warmth and edema as well as the expression of nociceptive mediators in the hindpaw skin of normal rats, (2) LY303870 administered intraperitoneally after fracture attenuated allodynia, hindpaw unweighting, warmth, and edema, as well as cytokine and NGF expression, (3) LY303870 blocked fracture-induced epidermal thickening and BrdU incorporation after fracture, (4) anti-NGF antibody blocked SP-induced allodynia but not warmth or edema, and (5) LY303870 had no effect on bone microarchitecture. Collectively our data indicate that SP acting through NK1 receptors supports the nociceptive and vascular components of CRPS, but not the bone-related changes.