Distal junctional failure after corrective surgery without pelvic fixation for thoracolumbar junctional kyphosis due to osteoporotic vertebral fracture.

BACKGROUND: Thoracolumbar junctional kyphosis (TLJK) due to osteoporotic vertebral fracture (OVF) negatively impacts patients' quality of life. The necessity of pelvic fixation in corrective surgery for TLJK due to OVF remains controversial. This study aimed to: 1) evaluate the surgical outcomes of major corrective surgery for thoracolumbar junctional kyphosis due to osteoporotic vertebral fracture, and 2) identify the risk factors for distal junctional failure to identify potential candidates for pelvic fixation. METHODS: Patients who underwent surgical correction (fixed TLJK>40°, OVF located at T11-L2, the lowermost instrumented vertebra at or above L5) were included. Sagittal vertical axis, pelvic tilt, pelvic incidence, thoracic kyphosis, lumbar lordosis (L1-S1), local kyphosis, and lower lumbar lordosis (L4-S1) were assessed. Proximal and distal junctional kyphosis (P/DJK) and failures (P/DJF) were evaluated. Pre/postoperative spinopelvic parameters were compared between DJF and non-DJF patients. RESULTS: Thirty-one patients (mean age: 72.3 ± 7.9 years) were included. PJK was observed in five patients (16.1%), while DJK in 11 (35.5%). Twelve cases (38.7%) were categorized as failure. Among the patients with PJK, there was only one patient (20%) categorized as PJF and required an additional surgery. Contrary, all of eleven patients with DJK were categorized as DJF, among whom six (54.5%) required additional surgery for pelvic fixation. In comparisons between DJF and non-DJF patients, there was no significant difference in pre/postoperative LK (pre/post, p = 0.725, p = 0.950). However, statistically significant differences were observed in the following preoperative alignment parameters: SVA (p = 0.014), LL (p = 0.001), LLL (p = 0.006), PT (p = 0.003), and PI-LL (p < 0.001). CONCLUSIONS: Spinopelvic parameters, which represent the compensatory function of lumbar hyperlordosis and pelvic retroversion, have notable impacts on surgical outcomes in correction surgery for TLJK due to OVF. Surgeons should consider each patient's compensatory function when choosing a surgical approach.

Atypical femoral fracture mimicking lumbar radiculopathy in two patients taking bisphosphonate long-term: A case report.

BACKGROUND: Atypical femoral fracture (AFF) is a rare complication in patients with osteoporosis undergoing long-term bisphosphonate therapy. The most common symptom of incomplete AFF is nonspecific thigh pain, which is often difficult to distinguish from other causes. CASE PRESENTATION: We present two cases of AFF misdiagnosed as lumbar radiculopathy. Both patients visited our hospital for thigh pain, and in both cases the findings of lumbar spine magnetic resonance imaging showed substantial nerve compression. These patients had been treated for lumbar radiculopathy, but localized symptoms became conspicuous and femoral radiographs revealed complete AFF. The initial radiographs were reviewed retrospectively and revealed slight lateral cortical thickening in the affected femur, denoting a missed incomplete AFF. Internal fixation with intramedullary nails was performed. CONCLUSIONS: AFF may mimic lumbar radiculopathy. Therefore, clinicians should consider AFF as a differential diagnosis in older patients with lumbar canal stenosis who are undergoing long-term bisphosphonate therapy and present with thigh pain.

Comparison of pedicle screw placement accuracy between two types of imaging support (Artis Zeego versus two-dimensional fluoroscopy): a cross-sectional observational study.

BACKGROUND: The pedicle screw system is widely used in spine surgery, and it provides rigid fixation and leads to successful subsequent deformity correction and bony fusion. The standard imaging technique for pedicle screw insertion is two-dimensional images obtained from C-arm-type X-ray fluoroscopy. Artis Zeego is an emerging intraoperative imaging technique that can provide conventional two-dimensional fluoroscopic images and rapid three-dimensional fluoroscopic computed tomography reconstruction imaging. The aim of this study is to compare the insertion accuracies of PS placement using Artis Zeego and conventional 2D X-ray fluoroscopy. METHODS: In this study, we retrospectively reviewed the postoperative images of thoracolumbar fusion patients who underwent surgery using pedicle screws between 2013 and 2018. Pedicle screw malplacement was assessed using a four-grade classification by Rao et al. Misplacement rates were compared between pedicle screws assisted with Artis Zeego and two-dimensional fluoroscopy. RESULTS: A total of 1107 pedicle screws in 153 patients were inserted using Artis Zeego, and 427 pedicle screws in 80 patients were inserted using fluoroscopy. The overall perforation rate was 4.2% (46 perforations of 1106 pedicle screws) in the Artis Zeego group and 7.7% (33 perforations of 427 pedicle screws) in the fluoroscopy group. In the Artis Zeego group, 43 (3.9%) screws were classified as grade 1, and three (0.3%) screws were classified as grade 2. In the fluoroscopy group, 21 (4.9%) screws were classified as grade 1, 10 (2.3%) screws were classified as grade 2, and 2 (0.5%) screws were classified as grade 3. The use of Artis Zeego was associated with a significantly lower screw malplacement rate than was the use of fluoroscopy (p < 0.001). CONCLUSIONS: Our results demonstrated that pedicle screw placement with Artis Zeego was associated with a lower malplacement rate than was conventional two-dimensional fluoroscopy. No severe malplacement was observed in the Artis Zeego group. Thus, Artis Zeego could be a good option for improving pedicle screw accuracy.

Radiological features of cervical spine in dropped head syndrome: a matched case-control study.

PURPOSE: Dropped head syndrome (DHS) is presumably caused by focal myopathy in the cervical posterior muscles; however, distinguishable radiological features of the cervical spine in DHS remain unidentified. This study investigated the radiological features of the cervical spine in dropped head syndrome. METHODS: The records of DHS patients and age- and sex-matched cervical spondylotic myelopathy (CSM) patients were reviewed. Cervical spinal parameters (C2-7, C2-4, and C5-7 angles) were assessed on lateral cervical spine radiographs. Quantitative radiographic evaluation of cervical spine degeneration was performed using the cervical degenerative index (CDI), which consists of four elements: disk space narrowing (DSN), endplate sclerosis, osteophyte formation, and listhesis. RESULTS: Forty-one DHS patients were included. Statistically significant differences were noted between the upper and lower cervical spine in the sagittal angle parameters on the neutral, flexion, and extension radiographs in DHS group, whereas no significant differences were observed in CSM group. CDI comparison showed significantly higher scores of DSN in C3/4, C4/5, C5/6, and C6/7; sclerosis in C5/6 and C6/7; and osteophyte formation in C4/5, C5/6, and C6/7 in DHS group than in CSM group. Comparison of listhesis scores revealed significant differences in the upper levels of the cervical spine (C2/3, C3/4, and C4/5) between two groups. CONCLUSION: Our results demonstrated that the characteristic radiological features in the cervical spine of DHS include lower-level dominant severe degenerative change and upper-level dominant spondylolisthesis. These findings suggest that degenerative changes in the cervical spine may also play a role in the onset and progression of DHS.

Chronic dysphagia caused by Laryngo-vertebral Synostosis after anterior fusion for cervical spine trauma: a case report.

BACKGROUND: Anterior cervical spine surgery is often associated with postoperative dysphagia, but chronic dysphagia caused by laryngo-vertebral synostosis is extremely rare. We report a case of chronic dysphagia caused by synostosis between the cricoid cartilage and cervical spine after anterior surgery for cervical spine trauma. CASE PRESENTATIONS: We present a case of a 39-year-old man who had sustained complex spine trauma at C5-6 associated with complete spinal cord injury at the age of 22; the patient presented with a 5-year history of chronic dysphagia. Computed tomography demonstrated posterior shift of the esophagus as well as calcification of the cricoid cartilage and its fusion to the right anterior tubercle of the C5 vertebra. A barium swallow study demonstrated significant barium aspiration into the airway and no laryngeal elevation. The patient underwent resection of the bony bridge and omohyoid muscle flap insertion. His symptoms ameliorated after surgery. CONCLUSION: Synostosis between the cricoid cartilage and cervical spine may occur associated with cervical spine trauma and causes chronic dysphagia. Resection of the fused part can improve dysphagia caused by this rare condition and omohyoid muscle flap might be a good option to prevent recurrence.

Impact of Spinopelvic sagittal alignment on the surgical outcomes of dropped head syndrome: a multi-center study.

BACKGROUND: Most of the previous studies about the surgical treatment of dropped head syndrome (DHS) are small case series, and their primary outcome measures were cervical alignment parameters. Therefore, little is known about the associations between pre- and postoperative global sagittal alignment in the whole spine and the clinical outcomes of the surgical treatment of DHS. In this study, we investigated the surgical outcomes of DHS, including correction of cervical and global spinal sagittal alignment. METHODS: This study was a retrospective observational study. Fifteen patients with DHS who had undergone correction surgery were enrolled. Surgical outcomes, including complications and implant failures, were investigated. We assessed cervical alignment parameters as well as spinopelvic global alignment parameters, including pelvic incidence (PI), lumbar lordosis (LL), and C7-sacral sagittal vertical axis (SVA). We examined the changes in these parameters using pre- and posoperative whole spine lateral radiographs. The parameters were compared between the failure and nonfailure groups. RESULTS: Recurrence of sagittal imbalance and horizontal gaze difficulty was observed in 6 cases (40%). In all, 3 cases (20%) exhibited a distal junctional failure and required multiple surgeries with extension of fusion. Of all the radiographic parameters compared between the failure and nonfailure groups, significant differences were only observed in pre and postoperative SVA and PI-LL. CONCLUSIONS: Our results suggest that the global sagittal alignment parameters, including PI-LL and SVA, were different between the patients with failure and non failure, and these parameters might have notable impacts on surgical outcomes. Surgeons should consider PI-LL and SVA while determining the surgical course for patients with DHS.

Lateral lumbar interbody fusion in revision surgery for restenosis after posterior decompression.

OBJECTIVE: The purpose of this study was to compare the clinical results of revision interbody fusion surgery between lateral lumbar interbody fusion (LLIF) and posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (TLIF) with propensity score (PS) adjustments and to investigate the efficacy of indirect decompression with LLIF in previously decompressed segments on the basis of radiological assessment. METHODS: A retrospective study of patients who underwent revision surgery for recurrence of neurological symptoms after posterior decompression surgery was performed. Postoperative complications and operative factors were evaluated and compared between LLIF and PLIF/TLIF. Moreover, postoperative improvement in cross-sectional areas (CSAs) in the spinal canal and intervertebral foramen was evaluated in LLIF cases. RESULTS: A total of 56 patients (21 and 35 cases of LLIF and PLIF/TLIF, respectively) were included. In the univariate analysis, the LLIF group had significantly more endplate injuries (p = 0.03) and neurological deficits (p = 0.042), whereas the PLIF/TLIF group demonstrated significantly more dural tears (p < 0.001), surgical site infections (SSIs) (p = 0.02), and estimated blood loss (EBL) (p < 0.001). After PS adjustments, the LLIF group still showed significantly more endplate injuries (p = 0.03), and the PLIF/TLIF group demonstrated significantly more dural tears (p < 0.001), EBL (p < 0.001), and operating time (p = 0.04). The PLIF/TLIF group showed a trend toward a higher incidence of SSI (p = 0.10). There was no statistically significant difference regarding improvement in the Japanese Orthopaedic Association scores between the 2 surgical procedures (p = 0.77). The CSAs in the spinal canal and foramen were both significantly improved (p < 0.001). CONCLUSIONS: LLIF is a safe, effective, and less invasive procedure with acceptable complication rates for revision surgery for previously decompressed segments. Therefore, LLIF can be an alternative to PLIF/TLIF for restenosis after posterior decompression surgery.

Overview of dropped head syndrome (Combined survey report of three facilities).

BACKGROUND: Dropped head syndrome (DHS) is a low prevalence and the clinical features remain unclear. The purpose of the present study was to clarify the general overview of DHS. METHODS: The subjects were 67 consecutive DHS patients (17 men and 50 women; average age 72.9 ± 10.2 years) presenting difficulty of horizontal gaze in up-right position. The patients' background, global spinal alignment, clinical findings and treatment were analyzed. RESULTS: The peak population of DHS was 75-79-year-old females. The comorbidities included Parkinson's disease in 9 cases, minor trauma in 9 cases, post-cervical operation in 3 cases, mental depression in 3 cases, malignant tumor in 3 cases, diabetes mellitus in 2 cases and rheumatoid arthritis in 2 cases. The C2-C7 cervical coronal vertical axis was distributed more to the right side (2.6 ± 12.8 mm). Regarding sagittal alignment, 24 cases (35.8%) showed negative balanced DHS (N-DHS) and 43 cases (64.2%) showed positive balanced DHS (P-DHS). There were significant differences in C2-C7 angle, T1S, LL and PI-LL between the two groups. Cervical or back pain was present in 62 cases (92.5%), and average numerical rating scale was 3.0 ± 2.6. Fourteen cases (20.9%) recovered (average 11.3 months), but 29 cases (43.3%) did not recover without surgery. Twenty-four cases (35.8%) underwent surgery, 20 for cervical spine and 4 for thoraco-lumbar spine, and horizontal gaze difficulty was improved in all patients post-surgery. CONCLUSION: DHS was mainly observed in elderly women. About 20% of DHS patients recovered without surgical treatment. DHS was accompanied by scoliosis in 37.3% of the cases.

[Fracture management and current concepts related to pregnancy-associated osteoporosis.]

Pregnancy-associated osteoporosis is a rare condition characterized by a transient but significant reduction in bone mineral density. To date, the underlying pathophysiological mechanisms remain unclear. Related symptoms include severe back or hip pain secondary to vertebral fractures and/or transient osteoporosis of the hip, which typically occur during the third trimester or during lactation. Although most women are managed conservatively, a few women need surgery. Prompt diagnosis and appropriate treatment is important not only for pain control, but also to improve the woman's future quality of life.

Single Intradiscal Administration of the Tumor Necrosis Factor-Alpha Inhibitor, Etanercept, for Patients with Discogenic Low Back Pain.

OBJECTIVE: To examine the analgesic effect of intradiscal administration of a tumor necrosis factor-αα (TNF-α) inhibitor in patients with discogenic low back pain (LBP). DESIGN: Prospective, randomized study. SETTING: Department of Orthopaedic Surgery, Chiba (Japan) University Hospital. SUBJECTS: Seventy-seven patients diagnosed with discogenic LBP. METHODS: Discogenic LBP patients were randomly assigned to the etanercept (n = 38; bupivacaine [2 mL] with etanercept [10 mg]) or control (n = 39; bupivacaine [2 mL]) groups. Patients received a single intradiscal injection. Numerical rating scale (NRS) scores for LBP at baseline, 1 day, and 1, 2, 4, and 8 weeks after the injection were recorded. The Oswestry disability index (ODI) scores at baseline and at 4 and 8 weeks after injection were evaluated. Postinjection complications were recorded and evaluated. RESULTS: In the etanercept group, the NRS scores were significantly lower than in the control group at every time point after the injection for 8 weeks (P < 0.05). Similarly, 4 weeks after the injection, the ODI score was lower in the etanercept group than in the control group (P < 0.05). However, the ODI scores were not significantly different at 8 weeks. Complications were not observed. CONCLUSIONS: Single intradiscal administration of a TNF-α inhibitor can alleviate intractable discogenic LBP for up to 8 weeks. TNF-α may be involved in discogenic pain pathogenesis. This procedure is a novel potential treatment; longer-term effectiveness trials are required in the future.

Evaluation of behavior and expression of NaV1.7 in dorsal root ganglia after sciatic nerve compression and application of nucleus pulposus in rats.

PURPOSE: The pathomechanisms of pain resulting from lumbar disc herniation have not been fully elucidated. Prostaglandins and cytokines generated at the inflammatory site produce associated pain; however, non-steroidal anti-inflammatory drugs and steroids are sometimes ineffective in patients. Tetrodotoxin-sensitive voltage-gated sodium (NaV) channels are related to sensory transmission in primary sensory nerves. The sodium channel NaV1.7 has emerged as an attractive analgesic target. The purpose of this study was to evaluate pain-related behavior and expression of NaV1.7 in dorsal root ganglia (DRG) after combined sciatic nerve compression and nucleus pulposus (NP) application in rats. METHODS: Rats were divided into three groups and underwent either sciatic nerve compression with NP for 2 s using forceps (n = 20), sham operation with neither compression nor NP (n = 20), or no operation (controls, n = 20). Mechanical hyperalgesia was measured every second day for three weeks using von Frey filaments. NaV1.7 expression in L5 DRG was examined 7 and 14 days after surgery using immunohistochemistry. The number of neurons immunoreactive for NaV1.7 was compared among the three groups. RESULTS: Mechanical hyperalgesia was found over the 14-day observation in the nerve compression plus NP application group, but not in the sham-operated or control groups (P < 0.05). NaV1.7 expression in L5 DRG was up-regulated in the nerve compression plus NP application group, compared with sham-operated and control rats (P < 0.01). CONCLUSIONS: Our results indicate that nerve compression plus NP application produces pain-related behavior. We conclude that NaV1.7 expression in DRG neurons may play an important role in mediating pain from sciatic nerves after compression injury and exposure to NP.

Risk factors for L5-S1 disk height reduction after lumbar posterolateral floating fusion surgery.

STUDY DESIGN: This is a retrospective study. OBJECTIVE: To investigate the risk factors for radiographic L5-S1 disk height reduction after lumbar posterolateral floating fusion surgery. SUMMARY OF BACKGROUND DATA: We investigated data from 86 patients (45 men) who underwent posterolateral floating fusion surgery from 2007 to 2010. The follow-up was from 2 to 6 years. The mean age of the patients was 65.4 years. METHODS: L5-S1 disk height was calculated and >2 mm reduction was defined as significant. Age, sex, height, weight, body mass index, number of fused levels, grade of disk degeneration, disk height and diameter, sacrolumbar alignment, alignment of fused level, achievement of union, and proximal adjacent segment disorder at final follow-up were compared. Univariate and multivariate logistic regressions were performed. RESULTS: L5-S1 disk height reduction occurred in 14 patients (30.2%). The number of fused levels was significantly greater (1.8±0.8 vs. 1.4±0.6) in patients without disk height reduction. Radiology showed a significant change of L1-S1 sacrolumbar alignment after surgery in patients without disk height reduction (0.3±6.6 vs. -4.5±7.6 degrees). The height of the disk posterior to the L5-S1 intervertebral disk before surgery was significantly greater (7.3±2.1 vs. 6.1±2.1 mm) in patients without disk height reduction. In multivariate logistic regression analysis, fusion of >3 levels was a significant risk factor for L5-S1 disk height reduction. CONCLUSIONS: In posterolateral floating fusion surgery, there was a higher risk of L5-S1 disk height reduction and consequent foraminal stenosis in patients with multiple-level fusion. Surgical methods and fusion levels should be chosen after considering their association with L5-S1 disk height reduction.

Quantitative evaluation of fatty degeneration of the supraspinatus and infraspinatus muscles using T2 mapping.

BACKGROUND: Although fatty degeneration of the rotator cuff muscles has been reported to affect the outcomes of rotator cuff repairs, only a few studies have attempted to quantitatively evaluate this degeneration. T2 mapping is a quantitative magnetic resonance imaging technique that potentially evaluates the concentration of fat in muscles. The purpose of this study was to investigate fatty degeneration of the rotator cuff muscles by using T2 mapping, as well as to evaluate the reliability of T2 measurement. METHODS: We obtained magnetic resonance images including T2 mapping from 184 shoulders (180 patients; 110 male patients [112 shoulders] and 70 female patients [72 shoulders]; mean age, 62 years [range, 16-84 years]). Eighty-three shoulders had no rotator cuff tear (group A), whereas 101 shoulders had tears, of which 62 were incomplete to medium (group B) and 39 were large to massive (group C). T2 values of the supraspinatus and infraspinatus muscles were measured and compared among groups. Intraobserver and interobserver variabilities also were examined. RESULTS: The mean T2 values of the supraspinatus in groups A, B, and C were 36.3 ± 4.7 milliseconds, 44.2 ± 11.3 milliseconds, and 57.0 ± 18.8 milliseconds, respectively. The mean T2 values of the infraspinatus in groups A, B, and C were 36.1 ± 5.1 milliseconds, 40.0 ± 11.1 milliseconds, and 51.9 ± 18.2 milliseconds, respectively. The T2 value significantly increased with the extent of the tear in both muscles. Both intraobserver and interobserver variabilities were more than 0.99. CONCLUSION: T2 mapping can be a reliable tool to quantify fatty degeneration of the rotator cuff muscles.

Additional decompression at adjacent segments leads to adjacent segment degeneration after PLIF.

PURPOSE: Adjacent segment degeneration (ASD) is one of the major complications of lumbar fusion. Several previous retrospective studies reported ASD after PLIF. However, few reports evaluated whether decompression surgery combined with fusion surgery increases the rate of complications in adjacent segments. The purpose of the current study was to investigate the degeneration in decompressed adjacent segments after PLIF. METHODS: A total of 23 patients (12 men, 11 women; average age, 58.6) who underwent PLIF surgery [1 level (n = 9), 2 levels (n = 8), 3 levels (n = 4), 4 levels (n = 2)] were included. Additional adjacent decompression above or below the level of interbody fusion was performed at 25 levels and no adjacent decompression was performed at 15 levels. We retrospectively investigated ASD by X-ray films of all 40 adjacent segments (above and below fusion level) and clinical outcomes of all 23 cases. RESULTS: Of the 40 adjacent segments, 19 (47.5%) showed ASD and 9 (22.5%) showed symptomatic ASD. In the 19 segments with ASD, ASD occurred in 16 of 25 (64.0%) segments at decompressed sites compared with 3 of 15 (20.0%) non-decompressed sites. The ratio of ASD in adjacent segments was significantly higher at decompressed sites than at non-decompressed sites (p < 0.01). CONCLUSION: ASD occurs frequently in association with additional decompression above or below the level of PLIF. In cases in which the adjacent segments require decompression, a surgical strategy that preserves as much of the posterior complex as possible should be selected.

L5 spinal nerve injury caused by misplacement of outwardly-inserted S1 pedicle screws.

PURPOSE: To evaluate L5 nerve root injuries caused by outwardly misplaced S1 pedicle screws. Pedicle screws remain the criterion standard for fixation of L5-S1 to correct lumbosacral instability. When inserting S1 pedicle screws, it is possible to injure the L5 nerve root if screws are inserted outwardly and the tip of the screw perforates the anterior cortex of the sacrum. Despite this risk, to our knowledge this type of injury has never been reported as a case series. METHODS: We experienced 2 cases of L5 nerve root injury caused by outwardly-inserted S1 pedicle screws. In both cases, bilateral S1 pedicle screws were inserted outwardly using a free-hand technique, and on one side, screws induced severe pain by impinging on an L5 root. Computed tomography after the selective rootgraphy of the injured nerve showed the nerve compressed laterally by screw threads in Case 1 and crushed between the screw threads and the sacral body in Case 2. RESULTS: In both cases, leg pain disappeared immediately after the infiltration of the nerve with lidocaine, but symptoms recurred within a few days in Case 1 and within an hour in Case 2. Conservative treatment of three spinal nerve infiltrations was effective in Case 1, but reinsertion of the rogue screw was necessary in Case 2. CONCLUSIONS: Surgeons should recognize that lateral inclination of S1 pedicle screws can cause L5 nerve root injury, which may require reinsertion of the screw, especially in cases where insertion is difficult because of overlapping surrounding muscle or bony tissue.

In-vivo transfection of the proopiomelanocortin gene, precursor of endogenous endorphin, by use of radial shock waves alleviates neuropathic pain.

BACKGROUND: Neuropathic pain is difficult to control and patient response to current treatment is often inadequate. Opioids have been widely used to treat a variety of pain states, but have several side effects. Endogenous opioids are clinically safe, but are not used for treatment because of rapid metabolism. However, in-vivo transfection of endogenous opioid genes could have a powerful and safe analgesic effect. The purpose of this study was to investigate the efficacy of proopiomelanocortin (POMC, a precursor of the endogenous opioid peptide ß-endorphin) gene transfer by use of radial shock waves (RSWs) in a rat neuropathic pain model. METHODS: As a neuropathic pain model, we used the Bennett chronic constriction injury (CCI) method. Immediately after CCI induction, POMC plasmid was injected into the rats' gastrocnemius muscle followed by exposure to RSW. Mechanical allodynia was measured for 4 weeks and dorsal root ganglion (DRG) neurons were sectioned and immunostained. RESULTS: ß-Endorphin blood levels and the number of ß-endorphin-immunoreactive (IR) muscle fibers increased over 28 days. ß-Endorphin overexpression caused a decrease in the number of calcitonin gene-related peptide (CGRP)-IR DRG neurons and suppressed neuropathic pain induced by CCI without causing adverse side effects. The size-distribution pattern of CGRP-IR DRG neurons shifted from small to large cells in the CCI group; however, the number of both small and large CGRP-IR cells decreased in the POMC group. CONCLUSION: POMC gene transfection alleviated allodynia and reduced CGRP expression in DRG neurons without adverse effects. CGRP is not produced in large neurons under physiologic conditions; however, in this study CGRP expression was shifted to large neurons after nerve injury. This change in cell-size distribution suggests that CGRP expression in large neurons is related to neuropathic pain. These findings suggest that POMC gene transfection using RSWs is a safe and effective treatment for neuropathic pain.

English publication rate of 3,205 abstracts presented at the Annual Meeting of the Japanese Orthopaedic Association and the Annual Research Meeting of the Japanese Orthopaedic Association.

BACKGROUND: Previous studies reported that the publication rate of abstracts presented at overseas meetings was around 50 %. The study objectives were to determine the rate of publication in English-language journals and the impact factor (IF) for all papers presented at the Annual Meeting of the Japanese Orthopaedic Association (JOA) and Annual Research Meeting of the Japanese Orthopaedic Association (JOAR), and to compare the publication rates and IFs from abstracts accepted for oral versus poster presentations. METHODS: Titles and first authors were identified for 1,676 abstracts of free papers accepted for presentation to the JOA in 2006 and 2007, and 1,529 abstracts to the JOAR from 2006 to 2008. We identified the associated journal publications by searching PubMed, and IFs were determined using the journal citation reports. The publication rates and IFs for papers accepted for oral versus poster presentations were compared using statistical analysis. RESULTS: The overall publication rate was 25.5 % from the JOA and 50 % from the JOAR. There were no significant differences in yearly publication rates, or between oral and poster presentations for each year. The average IFs for all publications from the JOA was 2.45 and that from the JOAR was 3.5. There were no significant differences in yearly IFs, or between oral and poster presentations for each year (P > 0.05). CONCLUSIONS: The rate from JOAR was similar to publication rates for abstracts presented at overseas orthopedic meetings, however, the rate from JOA was half that of publication rates for abstracts presented at overseas orthopedic meetings, indicating that JOA may provide a below average contribution of new medical data to the international scientific community. No significant difference in publication rates between oral and poster presentations were found, and this suggests a need for improvement of the review system for the annual meeting and that review scores at the meetings did not predict the publication fate of abstracts.

Effectiveness of Pulsed Radiofrequency Based on the Minimum Clinically Important Differences in Lumbar Spine-Related Pain in Patients without Recent Lumbar Surgery.

BACKGROUND: Pulsed radiofrequency (PRF) has been used for treatment of chronic pain in several body regions, including axial and radicular pain. However, a limited number of reports have specifically demonstrated the effectiveness of PRF for spine-related pain among nonsurgical patients. Therefore, we evaluated the effectiveness of PRF for lumbar spine-associated pain in patients without recent spine surgery, and identified the factors associated with clinically meaningful improvement in pain and quality of life. METHODS: Records of patients who underwent PRF for lumbar spine-related pain and were followed up over 6 months between 2019 and 2022 were retrospectively reviewed. Data on patient demographics, interventional factors, and patient-reported outcomes, such as the numerical rating scale (NRS) and EuroQol Group 5 Dimension 5-Level Quality of Life (EQ-5D-5 L), were collected. Patients were divided into 2 groups (responsive and nonresponsive) based on the NRS and EQ-5D-5 L scores using the previously reported minimal clinically important difference values of the NRS and EQ-5D-5 L as cutoffs, and baseline parameters were compared to identify contributing factors. RESULTS: Forty-three patients were included in the final analysis. The NRS and EQ-5D-5 L scores improved significantly at 3 and 6 months after PRF compared to baseline. The groups with NRS and EQ-5D-5 L improvement over the minimal clinically important difference had significantly higher baseline NRS and EQ-5D-5 L scores. CONCLUSIONS: Our results demonstrated that PRF improved pain and patient-reported outcomes for spine-related pain for at least 6 months in our patient cohort. PRF may be a good option for treating lumbar spine-related issues, even with severe pain and/or dysfunction.

Efficacy of epidural administration of anti-interleukin-6 receptor antibody onto spinal nerve for treatment of sciatica.

INTRODUCTION: Interleukin-6 (IL-6) is thought to play a crucial role in the radicular pain caused by lumbar spinal stenosis. However, efficacy of inhibition of IL-6 for sciatica in patients with lumbar spinal stenosis has not been clarified. The purpose of the current study was to examine the effect of the anti-IL-6 receptor monoclonal antibody, tocilizumab, on radicular pain by its epidural administration onto spinal nerves in patients with lumbar spinal stenosis. METHODS: Sixty patients with low back and radicular leg pain caused by spinal stenosis were investigated. In 30 patients, we infiltrated 2.0 mL of lidocaine and 80 mg of tocilizumab onto the affected spinal nerve, and 2.0 mL of lidocaine and 3.3 mg of dexamethasone were used in 30 patients. Low back pain, leg pain, and leg numbness were evaluated during 1 month after spinal nerve infiltration. RESULTS: Infiltration of tocilizumab was more effective than dexamethasone for leg pain (3 days, 1, 2, and 4 weeks), low back pain (3 days, 1, 2 and 4 weeks), and leg numbness (3 days, 1 and 2 weeks). No adverse event was observed in either group. CONCLUSION: Our results indicate that the epidural administration of an anti-IL-6 receptor monoclonal antibody, tocilizumab, onto the spinal nerve produced reduction of radicular leg pain, numbness, and low back pain without adverse event. IL-6 may be one of the inducers of pain caused by spinal stenosis in humans.

Percutaneously absorbed NSAIDs attenuate local production of proinflammatory cytokines and suppress the expression of c-Fos in the spinal cord of a rodent model of knee osteoarthritis.

BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used in clinical situations to reduce inflammation and pain. Percutaneous administration is one of the routes mainly used in Japan to deal with the pain from acute injuries, to chronic pain such as chronic low back pain and osteoarthritis (OA). There have been no studies that report the effect of percutaneous administration of NSAIDs on chronic pain in animal models. This study aimed to investigate the effect of percutaneously absorbed NSAIDs on a rodent model of OA. METHODS: OA was induced with an intra-articular injection of monoiodoacetate into the right knees (left knee was treated with saline, normal control) of female Sprague-Dawley rats. Physical evaluation, diameter, and the range of motion (ROM) of the knee joint, as well as pain-related behavior, were evaluated. Animals were killed and perfused 7 days after the intra-articular injection, and then local tissue from the knee [for cytokine assay: tumor necrosis factor (TNF)-α, interleukin (IL)-6, and nerve growth factor (NGF)] and spinal cord (immunostained for c-Fos protein reflecting neuronal excitation) were evaluated (n = 7 each). Twenty-eight days after the injection, the other rats were then divided into three groups and were identified by a plaster tape containing an NSAID or a vehicle applied to their OA (ipsilateral) knees: a vehicle-treated group, a loxoprofen-treated (lox) group, and a ketoprofen-treated (ket) group. The behavior elicited by von Frey hairs, inflammatory cytokines, and c-Fos protein at 0, 8, and 24 h after tape application were evaluated (n = 7 each). The plaster tapes contained corresponding NSAIDs used in clinical settings: lox 2.8 mg and ket 1.1 mg. Three of the OA animals were histologically evaluated. RESULTS: As the OA progressed, the ipsilateral knee joint showed OA-like appearance physically and histologically. The knee diameter increased and ROM decreased significantly (P < 0.05), showing histological OA-like cartilage degeneration. Pain threshold decreased significantly according to OA progression (P < 0.05). NSAID application significantly improved the threshold 24 h after application in both the lox and ket groups (P < 0.05) without any significant difference between groups. Cytokine concentrations and c-Fos were significantly suppressed in both lox and ket groups (P < 0.05). Lox suppressed TNF-α and NGF more than ket, whereas ket suppressed IL-6 more. CONCLUSION: Suppression of proinflammatory cytokines and c-Fos expression by clinically used NSAIDs suggests that their percutaneous administration may have an analgesic effect for treating chronic pain at a molecular level.