It was reported that nerve fibers were present in the inner part of lumbar intervertebral discs from patients with discogenic pain. Because there are no nerve fibers in the inner part of annulus fibrosus in normal condition, this finding suggests nerve ingrowth into the disc may be a cause of discogenic pain. Disc degeneration is often asymptomatic, thus, to understand the differences between symptomatic and asymptomatic disc, it is necessary to understand the pathogenesis of discogenic pain. We recently revealed that over 90% of the nociceptive dorsal root ganglion (DRG) neurons innervating the disc are sensitive to nerve growth factor (NGF), which is related to inflammatory pain. This indicates that discogenic pain is closely related to inflammation and NGF may play a key role. The increase of inflammatory mediators in symptomatic discs has been reported; we therefore studied the effects of disc inflammation and found that it induces sensitization of disc-innervating neurons and nerve ingrowth into the disc. More recently, it was shown that annular rupture induces nerve ingrowth, an increase of inflammatory mediators in the disc, and upregulation of calcitonin gene-related peptide, a pain-related molecule in DRGs. These findings led us to believe that annular rupture triggers inflammation and nerve ingrowth, inflammatory mediators then further promote nerve ingrowth into the disc and sensitization of disc-innervating neurons, and discogenic pain finally becomes chronic. NGF, found in symptomatic discs, may act as a key factor in generating chronic discogenic pain by sensitizing disc-innervating neurons and stimulating nerve ingrowth into the disc.
Calcitonin Gene-Related Peptide ; Diagnosis-Related Groups ; Ganglia, Spinal ; Humans ; Inflammation ; Intervertebral Disc ; Intervertebral Disc Degeneration ; Nerve Fibers ; Nerve Growth Factor ; Neurons ; Rupture ; Up-Regulation

STUDY DESIGN: Retrospective cohort study. PURPOSE: To investigate the effect of spinal correction on respiratory muscle strength in patients with Duchenne muscular dystrophy (DMD). OVERVIEW OF LITERATURE: Several studies have reported that scoliosis correction in patients with DMD does not improve pulmonary function. In these studies, pulmonary function was evaluated using the traditional spirometric values of percent vital capacity (%VC) and percent forced vital capacity (%FVC). However, traditional spirometry may not be suitable for patients with DMD because the results can be influenced by patient fatigue or level of understanding. Therefore, we evaluated respiratory function focusing on respiratory muscle strength using maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and sniff nasal inspiratory pressure (SNIP), in addition to %VC and %FVC. METHODS: We retrospectively reviewed 16 patients with DMD who underwent spinal correction surgery between 2006 and 2011 at Kitasato University Hospital. All patients were males, and the mean age was 13.5 years. Respiratory muscle strength was evaluated using MIP, MEP, and SNIP. Measurements were obtained preoperatively and at 1 and 6 months postoperatively, and %VC and %FVC were obtained preoperatively and within 6 months postoperatively. RESULTS: The mean preoperative and postoperative %VC values were 54.0% and 51.7%, whereas the mean %FVC values were 53.9% and 53.2%, respectively. The mean MIP, MEP, and SNIP values obtained preoperatively and at 1 and 6 months postoperatively were as follows: MIP, 40.5, 42.7 and 47.2 cm H₂O; MEP, 26.0, 28.0, and 29.0 cm H₂O; and SNIP, 33.4, 33.0, and 33.0 cm H₂O; respectively. The mean MIP and MEP values significantly improved postoperatively. There were no significant differences in SNIP, %VC, or %FVC preand postoperatively. CONCLUSIONS: By focusing on respiratory muscle strength, our results suggest that scoliosis correction in patients with DMD might have a favorable effect on respiratory function.
Cohort Studies ; Fatigue ; Humans ; Male ; Muscular Dystrophy, Duchenne* ; Respiratory Muscles* ; Retrospective Studies ; Scoliosis* ; Spirometry ; Vital Capacity

PURPOSE: Bupivacaine is commonly used for the treatment of back pain and the diagnosis of its origin. Nonunion is sometimes observed after spinal fusion surgery; however, whether the nonunion causes pain is controversial. In the current study, we aimed to detect painful nonunion by injecting bupivacaine into the disc space of patients with nonunion after anterior lumbar interbody fusion (ALIF) surgery for discogenic low back pain. MATERIALS AND METHODS: From 52 patients with low back pain, we selected 42 who showed disc degeneration at only one level (L4-L5 or L5-S1) on magnetic resonance imaging and were diagnosed by pain provocation on discography and pain relief by discoblock (the injection of bupivacaine). They underwent ALIF surgery. If the patients showed low back pain and nonunion 2 years after surgery, we injected bupivacaine into the nonunion disc space. Patients showing pain relief after injection of bupivacaine underwent additional posterior fixation using pedicle screws. These patients were followed up 2 years after the revision surgery. RESULTS: Of the 42 patient subjects, 7 showed nonunion. Four of them did not show low back pain; whereas 3 showed moderate or severe low back pain. These 3 patients showed pain reduction after injection of bupivacaine into their nonunion disc space and underwent additional posterior fixation. They showed bony union and pain relief 2 years after the revision surgery. CONCLUSION: Injection of bupivacaine into the nonunion disc space after ALIF surgery for discogenic low back pain is useful for diagnosis of the origin of pain.
Back Pain ; Bupivacaine* ; Diagnosis ; Humans ; Intervertebral Disc ; Intervertebral Disc Degeneration ; Low Back Pain* ; Magnetic Resonance Imaging ; Methods ; Spinal Fusion ; Spine

STUDY DESIGN: Retrospective case series. PURPOSE: To examine the most effective duration of teriparatide use for spinal fusion in women with postmenopausal osteoporosis. OVERVIEW OF LITERATURE: We reported that daily subcutaneous injection of teriparatide (parathyroid hormone) significantly improved bone union after instrumented lumbar posterolateral fusion (PLF) in women with postmenopausal osteoporosis when compared with oral administration of bisphosphonate. However, the most effective duration of teriparatide use for spinal fusion has not been explored. METHODS: Forty-five women with osteoporosis diagnosed with degenerative spondylolisthesis from one of the three treatment groups were evaluated based on: short-duration treatment (average, 5.5 months; n=15; daily subcutaneous injection of 20 microg teriparatide), long-duration treatment (average, 13.0 months; n=15; daily subcutaneous injection of 20 microg teriparatide), and bisphosphonate treatment (average, 13.0 months; n=15; weekly oral administration of 17.5 mg risedronate). All patients underwent PLF with a local bone graft. Fusion rate and duration of bone union were evaluated 1.5 years after surgery. RESULTS: Bone union rate and average duration for bone union were 92% and 7.5 months in the long-duration treatment group, 80% and 8.5 months in the short-duration treatment group, and 70% and 10.0 months in the bisphosphonate treatment group, respectively. Results of bone union rate and average duration for bone union in the teriparatide treatment groups were significantly superior to those in the bisphosphonate treatment group (p<0.05); whereas, significantly superior results were observed in long-duration treatment group when compared with short-duration treatment group (p<0.05). CONCLUSIONS: Daily injection of teriparatide for bone union was more effective than oral administration of bisphosphonate. Furthermore, a longer period of teriparatide treatment for bone union was more effective than a shorter period of same treatment.
Administration, Oral ; Female ; Humans ; Injections, Subcutaneous ; Osteoporosis ; Osteoporosis, Postmenopausal ; Retrospective Studies ; Spinal Fusion ; Spondylolisthesis ; Teriparatide* ; Transplants

PURPOSE: Opioids improve pain from knee and hip osteoarthritis (OA) and decrease the functional impairment of patients. However, there is a possibility that opioids induce analgesia and suppress the physiological pain of OA in patients, thereby inducing the progression of OA changes in these patients. The purpose of the current study was to investigate the possibility of progressive changes in OA among patients using opioids. MATERIALS AND METHODS: Two hundred knee or hip OA patients were evaluated in the current prospective, randomized, active-controlled study. Patients were randomized 1:1:1 into three parallel treatment groups: loxoprofen, tramadol/acetaminophen, and transdermal fentanyl groups. Medication was administered for 12 weeks. Pain scores and progressive OA changes on X-ray films were evaluated. RESULTS: Overall, pain relief was obtained by all three groups. Most patients did not show progressive OA changes; however, 3 patients in the transdermal fentanyl group showed progressive OA changes during the 12 weeks of treatment. These 3 patients used significantly higher doses than others in the transdermal fentanyl group. Additionally, the average pain score for these 3 patients was significantly lower than the average pain score for the other patients in the transdermal fentanyl group. CONCLUSION: Fentanyl may induce progressive changes in knee or hip OA during a relatively short period, compared with oral Non-Steroidal Anti-Inflammatory Drugs or tramadol.
Aged ; Aged, 80 and over ; Analgesics, Opioid/*adverse effects/therapeutic use ; Disease Progression ; Female ; Fentanyl/*adverse effects/therapeutic use ; Humans ; Male ; Middle Aged ; Osteoarthritis, Hip/*drug therapy/radiography ; Osteoarthritis, Knee/*drug therapy/radiography ; Pain/drug therapy

PURPOSE: Chronic low back pain is a common clinical problem. As medication, non-steroidal anti-inflammatory drugs are generally used; however, they are sometimes non-effective. Recently, opioids have been used for the treatment of chronic low back pain, and since 2010, transdermal fentanyl has been used to treat chronic non-cancer pain in Japan. The purpose of the current study was to examine the efficacy of transdermal fentanyl in the treatment of chronic low back pain. MATERIALS AND METHODS: This study included patients (n=62) that suffered from chronic low back pain and were non-responsive to non-steroidal anti-inflammatory drugs. Their conditions consisted of non-specific low back pain, multiple back operations, and specific low back pain awaiting surgery. Patients were given transdermal fentanyl for chronic low back pain. Scores of the visual analogue scale and the Oswestry Disability Index, as well as adverse events were evaluated before and after therapy. RESULTS: Overall, visual analogue scale scores and Oswestry Disability Index scores improved significantly after treatment. Transdermal fentanyl (12.5 to 50 microg/h) was effective in reducing low back pain in 45 of 62 patients; however, it was not effective in 17 patients. Patients who experienced the most improvement were those with specific low back pain awaiting surgery. Adverse events were seen in 40% of patients (constipation, 29%; nausea, 24%; itching, 24%). CONCLUSION: Disability Index scores in 73% of patients, especially those with specific low back pain awaiting surgery; however, it did not decrease pain in 27% of patients, including patients with non-specific low back pain or multiple back operations.
Administration, Cutaneous ; Adult ; Aged ; Aged, 80 and over ; Chronic Disease ; Female ; Fentanyl/*administration & dosage/*therapeutic use ; Humans ; Low Back Pain/*drug therapy ; Male ; Middle Aged ; Young Adult

STUDY DESIGN: Retrospective case series. PURPOSE: To classify back muscle degeneration using magnetic resonance imaging (MRI) and investigate its relationship with back pain after surgery. OVERVIEW OF LITERATURE: Back muscle injury and degeneration often occurs after posterior lumbar surgery, and the degeneration may be a cause of back pain. However, the relationship between back muscle degeneration and back pain remains controversial. METHODS: A total of 84 patients (average age, 65.1 years; 38 men, 46 women) with lumbar spinal stenosis underwent posterior decompression surgery alone. MRI (1.5 tesla) was evaluated before and more than a year after surgery in all patients. Muscle on MRI was classified into three categories: low intensity in T1-weighted imaging, high intensity in T2-weighted imaging (type 1), high intensity in both T1- and T2-weighted images (type 2), and low intensity in both T1- and T2-weighted imaging (type 3). The prevalence of the types and their relationship with back pain (determined on a visual analog scale) were evaluated. RESULTS: MRI revealed muscle degeneration in all patients after surgery (type 1, 6%; type 2, 82%; and type 3, 12%). Type 2 was significantly more frequent compared with types 1 and 3 (p<0.01). Low back pain was significantly improved after surgery (p<0.01). Low back pain was not associated with any MRI type of muscle degeneration after surgery (p>0.05). CONCLUSIONS: Various pathologies of back muscle degeneration after posterior lumbar surgery were revealed. Type 2 (fatty) change was most frequent, and other patients had type 3 (scar) or type 1 (inflammation or water-like) changes. According to the Modic classification of bone marrow changes, Modic type 1 change is associated with inflammation and back pain. However, no particular type of back muscle degeneration was correlated with back pain after surgery.
Back Muscles* ; Back Pain ; Bone Marrow ; Classification* ; Decompression ; Humans ; Inflammation ; Low Back Pain* ; Magnetic Resonance Imaging ; Male ; Pathology ; Prevalence ; Retrospective Studies ; Spinal Stenosis

STUDY DESIGN: Retrospective case series. PURPOSE: To determine whether symptoms predict surgical outcomes for patients with discogenic low back pain (DLBP). OVERVIEW OF LITERATURE: Specific diagnosis of DLBP remains difficult. Worsening of pain on flexion is a reported symptom of DLBP. This study sought to determine whether symptoms predict surgical outcomes for patients with DLBP. METHODS: We investigated 127 patients with low back pain (LBP) and no dominant radicular pain. Magnetic resonance imaging was used to select patients with disc degeneration at only one level. If pain was provoked during discography, we performed fusion surgery (87 patients). Visual analogue scale score and responses to a questionnaire regarding symptoms including worsening of pain on flexion or extension were assessed. Symptom sites before surgery were categorized into LBP alone, or LBP plus referred inguinal or leg pain. We followed 77 patients (average 3.0 years) and compared symptoms before surgery with surgical outcome. RESULTS: Sixty-three patients with a good outcome showed postsurgical pain relief (≥60% pain relief) and 14 patients with a poor outcome did not (<60% pain relief). In patients with good outcomes, worsening of LBP was evident in 65% of cases on flexion and in 35% on extension. However, these findings were not significantly different from those in patients with poor outcomes. The percentage of patients with LBP alone was significantly lower and the percentage of patients with LBP plus referred inguinal or leg pain was significantly higher in the group with good surgical outcome compared with patients in the group with poor surgical outcome (p<0.05). CONCLUSIONS: Worsening of pain on extension may be a symptom of DLBP. Surgical outcomes were superior in patients with both LBP and either referred inguinal or leg pain compared with those having LBP alone.
Diagnosis ; Humans ; Intervertebral Disc ; Intervertebral Disc Degeneration ; Leg ; Low Back Pain* ; Magnetic Resonance Imaging ; Retrospective Studies

STUDY DESIGN: Retrospective case series. PURPOSE: To classify back muscle degeneration using magnetic resonance imaging (MRI) and investigate its relationship with back pain after surgery. OVERVIEW OF LITERATURE: Back muscle injury and degeneration often occurs after posterior lumbar surgery, and the degeneration may be a cause of back pain. However, the relationship between back muscle degeneration and back pain remains controversial. METHODS: A total of 84 patients (average age, 65.1 years; 38 men, 46 women) with lumbar spinal stenosis underwent posterior decompression surgery alone. MRI (1.5 tesla) was evaluated before and more than a year after surgery in all patients. Muscle on MRI was classified into three categories: low intensity in T1-weighted imaging, high intensity in T2-weighted imaging (type 1), high intensity in both T1- and T2-weighted images (type 2), and low intensity in both T1- and T2-weighted imaging (type 3). The prevalence of the types and their relationship with back pain (determined on a visual analog scale) were evaluated. RESULTS: MRI revealed muscle degeneration in all patients after surgery (type 1, 6%; type 2, 82%; and type 3, 12%). Type 2 was significantly more frequent compared with types 1 and 3 (p<0.01). Low back pain was significantly improved after surgery (p<0.01). Low back pain was not associated with any MRI type of muscle degeneration after surgery (p>0.05). CONCLUSIONS: Various pathologies of back muscle degeneration after posterior lumbar surgery were revealed. Type 2 (fatty) change was most frequent, and other patients had type 3 (scar) or type 1 (inflammation or water-like) changes. According to the Modic classification of bone marrow changes, Modic type 1 change is associated with inflammation and back pain. However, no particular type of back muscle degeneration was correlated with back pain after surgery.
Back Muscles* ; Back Pain ; Bone Marrow ; Classification* ; Decompression ; Humans ; Inflammation ; Low Back Pain* ; Magnetic Resonance Imaging ; Male ; Pathology ; Prevalence ; Retrospective Studies ; Spinal Stenosis

STUDY DESIGN: Retrospective case series. PURPOSE: To determine whether symptoms predict surgical outcomes for patients with discogenic low back pain (DLBP). OVERVIEW OF LITERATURE: Specific diagnosis of DLBP remains difficult. Worsening of pain on flexion is a reported symptom of DLBP. This study sought to determine whether symptoms predict surgical outcomes for patients with DLBP. METHODS: We investigated 127 patients with low back pain (LBP) and no dominant radicular pain. Magnetic resonance imaging was used to select patients with disc degeneration at only one level. If pain was provoked during discography, we performed fusion surgery (87 patients). Visual analogue scale score and responses to a questionnaire regarding symptoms including worsening of pain on flexion or extension were assessed. Symptom sites before surgery were categorized into LBP alone, or LBP plus referred inguinal or leg pain. We followed 77 patients (average 3.0 years) and compared symptoms before surgery with surgical outcome. RESULTS: Sixty-three patients with a good outcome showed postsurgical pain relief (≥60% pain relief) and 14 patients with a poor outcome did not (<60% pain relief). In patients with good outcomes, worsening of LBP was evident in 65% of cases on flexion and in 35% on extension. However, these findings were not significantly different from those in patients with poor outcomes. The percentage of patients with LBP alone was significantly lower and the percentage of patients with LBP plus referred inguinal or leg pain was significantly higher in the group with good surgical outcome compared with patients in the group with poor surgical outcome (p<0.05). CONCLUSIONS: Worsening of pain on extension may be a symptom of DLBP. Surgical outcomes were superior in patients with both LBP and either referred inguinal or leg pain compared with those having LBP alone.
Diagnosis ; Humans ; Intervertebral Disc ; Intervertebral Disc Degeneration ; Leg ; Low Back Pain* ; Magnetic Resonance Imaging ; Retrospective Studies