Yasuhiro Oikawa

Comparison of teriparatide and bisphosphonate treatment to reduce pedicle screw loosening after lumbar spinal fusion surgery in postmenopausal women with osteoporosis from a bone quality perspective.

Study Design. Prospective study. Objective. To examine the efficacy of teriparatide or bisphosphonate treatment to reduce pedicle screw (PS) loosening after instrumented lumbar posterolateral fusion in postmenopausal women with osteoporosis. Summary of Background Data. Failure of fixation caused by loosening of PSs in osteoporosis is a problem in spinal surgery. Oral administration of bisphosphonate or intermittent injection of parathyroid hormone treatment increases bone mass and reduces the risk of osteoporotic vertebral fractures. Although these treatments may be factor in improving bone quality, a clinical study of the efficacy of bisphosphonate or parathyroid hormone for reducing PS loosening that addresses the quality of the bone marrow and pedicle cortex has not yet been reported. Methods. Sixty-two women with osteoporosis diagnosed with degenerative spondylolisthesis were divided into 3 groups: a teriparatide group (daily subcutaneous injection of 20 &mgr;g of teriparatide, n = 20), a bisphosphonate group (daily oral administration 2.5 mg of risedronate, n = 20), and a control group (without medication for osteoporosis, n = 22). All patients underwent decompression and 1- or 2-level instrumented posterolateral fusion with a local bone graft. Loosening of PSs and surgical outcome were evaluated radiographically, clinically, and by computed tomography 12 months after surgery. Results. At 12-month follow-up, the incidence of PS loosening was 7% to 13% in the teriparatide group, 13% to 26% in the risedronate group, and 15% to 25% in the control group. The incidence of PS loosening in the teriparatide group was significantly lower than that in the risedronate or the control group (P < 0.05). In contrast, the extent of PS loosening in the risedronate group was not significantly different from that in the control group (P > 0.05). Conclusion. Our findings suggest that administration of teriparatide increased the quality of the lumbar spine bone marrow and pedicle cortex. Level of Evidence: 3

Existence of a Neuropathic Pain Component in Patients with Osteoarthritis of the Knee

Purpose Pain from osteoarthritis (OA) is generally classified as nociceptive (inflammatory). Animal models of knee OA have shown that sensory nerve fibers innervating the knee are significantly damaged with destruction of subchondral bone junction, and induce neuropathic pain (NP). Our objective was to examine NP in the knees of OA patients using painDETECT (an NP questionnaire) and to evaluate the relationship between NP, pain intensity, and stage of OA. Materials and Methods Ninety-two knee OA patients were evaluated in this study. Pain scores using Visual Analogue Scales (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), painDETECT, duration of symptoms, severity of OA using the Kellgren-Lawrence (KL) system, and amount of joint fluid were evaluated and compared using a Spearmans correlation coefficient by rank test. Results Our study identified at least 5.4% of our knee OA patients as likely to have NP and 15.2% as possibly having NP. The painDETECT score was significantly correlated with the VAS and WOMAC pain severity. Compared with the painDETECT score, there was a tendency for positive correlation with the KL grade, and tendency for negative correlation with the existence and amount of joint fluid, but these correlations were not significant. Conclusion PainDETECT scores classified 5.4% of pain from knee OA as NP. NP tended to be seen in patients with less joint fluid and increased KL grade, both of which corresponded to late stages of OA. It is important to consider the existence of NP in the treatment of knee OA pain.

Teriparatide accelerates lumbar posterolateral fusion in women with postmenopausal osteoporosis: prospective study.

Study Design. Prospective trial. Objective. To examine the clinical efficacy of teriparatide for bone union after instrumented lumbar posterolateral fusion using local bone grafting in women with postmenopausal osteoporosis. Summary of Background Data. Intermittent parathyroid hormone (PTH) treatment increases bone mass and reduces the risk for osteoporotic vertebral fractures. Recombinant human PTH (1–34) has already been approved as a treatment for severe osteoporosis. Preclinical data support the efficacy of PTH for lumbar spinal fusion. However, clinical results of PTH for spinal fusion have not yet been reported. Methods. Fifty-seven women with osteoporosis diagnosed with degenerative spondylolisthesis were divided into 2 treatment groups, a teriparatide group (n = 29; daily subcutaneous injection of 20 &mgr;g of teriparatide) and a bisphosphonate group (n = 28; weekly oral administration of 17.5 mg of risedronate). All patients underwent decompression and 1- or 2-level instrumented posterolateral fusion with a local bone graft. Fusion rate, duration of bone union, and pain scores were evaluated 1 year after surgery. Results. Pain scores improved after surgery; however, no significant difference was noted between the groups after surgery. The rate of bone union was 82% in the teriparatide group and 68% in the bisphosphonate group. Average duration of bone union was 8 months in the teriparatide group and 10 months in the bisphosphonate group. The rate of bone union and average of duration of bone union in the teriparatide group patients were significantly superior to those in the bisphosphonate group. Conclusion. Daily subcutaneous injection of teriparatide for bone union using local bone grafting after instrumented lumbar posterolateral fusion in women with postmenopausal osteoporosis was more effective than oral administration of bisphosphonate.

Difficulty of Diagnosing the Origin of Lower Leg Pain in Patients With Both Lumbar Spinal Stenosis and Hip Joint Osteoarthritis

Study Design. Case series. Objective. To present the difficulty of diagnosing the origin of lower leg pain in patients with lumbar spinal stenosis and hip joint arthritis. Summary of Background Data. Pain arising from a degenerated hip joint is sometimes localized to the lower leg. Patients with lumbar spinal disease may also show radicular pain corresponding to the lower leg area. If patients present with both conditions and only pain at the lower leg, it is difficult to determine the origin of the pain. Methods. We reviewed 420 patients who had leg pain with lumbar spinal stenosis diagnosed by myelography, computed tomography after myelography, or magnetic resonance imaging. Pain only at the ipsilateral lateral aspect of the lower leg but slight low back pain or pain around the hip joint was shown in 4 patients who had lumbar spinal stenosis and hip osteoarthritis. The symptoms resolved after L5 spinal nerve block, but remained after lidocaine infiltration into the hip joint. We performed decompression and posterolateral fusion surgery for these 4 patients. Results. Leg pain did not resolve after lumbar surgery in all patients. Conservative treatment was not effective from 6 to 12 months, so ultimately we performed ipsilateral total hip replacement for all patients and they became symptom-free. Conclusion. It is difficult to determine the origin of lower leg pain by spinal nerve block and hip joint block in patients with lumbar spinal stenosis and hip osteoarthritis. We take this into consideration before surgery.

ISSLS prize winner: disc dynamic compression in rats produces long-lasting increases in inflammatory mediators in discs and induces long-lasting nerve injury and regeneration of the afferent fibers innervating discs: a pathomechanism for chronic discogenic low back pain.

Study Design. Animal model of intravertebral disc (IVD) degeneration. Objective. To examine production of inflammatory mediators in IVDs and neuropeptides in dorsal root ganglia (DRGs) in rat models of IVD compression and injury. Summary of Background Data. Sensory nerve fibers in IVDs and inflammatory mediator responses have been verified in animal models of IVD injury. However, the IVD injury in animals incompletely models degenerated human IVDs causing discogenic low back pain, because human IVDs are also subject to compression. Methods. Experimental groups (controls, IVD injury, IVD compression, and their combination) of Sprague Dawley rats were prepared. Fluoro-Gold (FG; Fluorochrome, Denver, CO) was applied into coccygeal IVDs. Inflammatory mediators in IVDs, including nerve growth factor, tumor necrosis factor &agr;, interleukin 1&bgr;, and interleukin 6, were quantified using enzyme-linked immunosorbent assays. DRGs were immunostained for calcitonin gene-related peptide, activating transcription factor 3, and growth-associated phosphoprotein 43. Results. The upregulation of inflammatory mediators was transient in the IVD injury group but delayed and long-lasting in the IVD compression group. When the IVD injury and compression were combined, the upregulation of inflammatory mediators was long-lasting through 8 weeks. The proportion of calcitonin gene-related peptide–immunoreactive neurons among Fluoro-Gold–labeled neurons remained significantly higher in the IVD injury, compression, and combination groups than in the controls. In contrast, increases in the proportions of activating transcription factor 3–immunoreactive or growth-associated phosphoprotein 43–immunoreactive neurons in the IVD injury group animals were transient but long-lasting in the compression and combination groups compared with controls. Conclusion. Disc injury in rats produces persistent increases in neuropeptides in DRGs but only transient increases in inflammatory mediators in IVDs. On the contrary, disc compression in rats produces a long-lasting increase in inflammatory mediators in IVDs and neuropeptides in DRGs. Moreover, disc compression induces persistent nerve injury and regeneration of the afferent fibers innervating IVDs.

Assessment of pain behavior in a rat model of intervertebral disc injury using the CatWalk gait analysis system.

Study Design. Pain behavior and immunohistological analysis in intervertebral disc (IVD) injury model. Objective. To investigate pain behavior in a rat model of IVD injury using the CatWalk system. Summary of Background Data. There are few reports examining low back pain behavior in animal models. The CatWalk is a computer-assisted gait analysis system that provides an automated way to assess gait function and pain-related alterations of this behavior. Methods. In the IVD injury group, L5–L6 IVDs were injured with a 24-gauge needle. Simultaneously, the neurotracer Fluoro-Gold (FG; Fluorochrome, Denver, CO) was injected into the L5–L6 IVDs. In the sham group, FG was injected into the L5–L6 IVDs only. Animals in the control group received no operation. One, 2, 3, and 4 weeks after surgery, the gait of rats in the 3 groups was investigated using the CatWalk system. One, 2, and 4 weeks after surgery, in IVD injury and sham groups, dorsal root ganglions from the L1 to L6 levels were resected. Dorsal root ganglions were immunostained for calcitonin gene-related peptide. Results. In the IVD injury group, the mean stands of hind paws and the mean duty cycle of front paws at some time points were significantly higher than those in the sham group. Furthermore, the mean stride length of the front and hind paws and the mean swing speed of the front and hind paws at some time points were significantly shorter than those in the sham group. The proportion of calcitonin gene-related peptide-immunoreactive, FG-labeled neurons among all FG-labeled dorsal root ganglion neurons in the IVD injury group was significantly higher than the corresponding proportion in the sham group. Conclusion. These results suggest that IVD injury produced significant changes in rat gait, including longer stance phases and shorter strides. In the future, we may be able to apply the CatWalk system to the evaluation of behavior associated with pain in models of low back pain. Level of Evidence: N/A

Mini-Open Anterior Retroperitoneal Lumbar Interbody Fusion: Oblique Lateral Interbody Fusion for Lumbar Spinal Degeneration Disease

Purpose Surgery for lumbar spinal degeneration disease is widely performed. While posterior decompression and fusion are popular, anterior lumbar interbody fusion (ALIF) is also used for treatment. Extreme lateral interbody fusion (XLIF) is commonly used for noninvasive ALIF; however, several complications, such as spinal nerve and psoas muscle injury, have been reported. In the current study, we examined the clinical efficacy and complications of oblique lateral interbody fusion (OLIF) for lumbar spinal degeneration disease. Materials and Methods Thirty-five patients with degenerated spondylolisthesis, discogenic pain, and kyphoscoliosis were examined. All patients underwent OLIF surgery (using a cage and bone graft from the iliac crest) with or without posterior decompression, without real-time electromyography monitoring. Posterior screws were used in all patients. Visual analog scale (VAS) score and Oswestry Disability Index (ODI) were evaluated before and 6 months after surgery. Surgical complications were also evaluated. Results Pain scores significantly improved after surgery, compared to those before surgery (p<0.05). There was no patient who underwent revision surgery. There was no spinal nerve, major vessel, peritoneal, or urinary injury. Few patients showed symptoms from psoas invasion. Conclusion OLIF surgery produced good surgical results without any major complication.

Efficacy of combination of meloxicam and pregabalin for pain in knee osteoarthritis.

Purpose Osteoarthritic pain is largely considered to be inflammatory pain. Sensory nerve fibers innervating the knee have been shown to be significantly damaged in rat models of knee osteoarthritis (OA) in which the subchondral bone junction is destroyed, and this induces neuropathic pain (NP). Pregabalin was developed as a pain killer for NP; however, there are no reports on pregabalin use in OA patients. The purpose of this study was to investigate the efficacy of pregabalin for pain in OA patients. Materials and Methods Eighty-nine knee OA patients were evaluated in this randomized prospective study. Patients were divided into meloxicam, pregabalin, and meloxicam+pregabalin groups. Pain scores were evaluated before and 4 weeks after drug application using a visual analogue scale (VAS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Pain scales among groups were compared using a Kruskal-Wallis test. Results Before drug application, there was no significant difference in VAS and WOMAC scores among the three groups (p>0.05). Significant pain relief was seen in the meloxicam+pregabalin group in VAS at 1, 2, and 4 weeks, and WOMAC score at 4 weeks, compared with the other groups (p<0.05). No significant pain relief was seen in the meloxicam only group in VAS during 4 weeks and WOMAC score at 4 weeks compared with the pregabalin only group (p>0.05). Conclusion Meloxicam+pregabalin was effective for pain in OA patients. This finding suggests that OA pain is a combination of inflammatory and NP.

Mini-Open Anterior Retroperitoneal Lumbar Interbody Fusion: Oblique Lateral Interbody Fusion for Degenerated Lumbar Spinal Kyphoscoliosis

Study Design Prospective case series. Purpose To examine the clinical efficacy of mini-open anterior retroperitoneal lumbar interbody fusion: oblique lateral interbody fusion (OLIF) for degenerated lumbar spinal kyphoscoliosis. Overview of Literature The existing surgical procedures for the treatment of spinal kyphotic deformity, including Smith-Petersen osteotomy, pedicle subtraction osteotomy, and vertebral column resection procedures, are invasive in nature. Extreme lateral interbody fusion to provide less invasive treatment of the deformity has been reported, but complications including spinal nerve and psoas muscle injury have been noted. In the current study, we examined the clinical efficacy and complications of OLIF for degenerated lumbar spinal kyphoscoliosis. Methods Twelve patients with degenerated lumbar spinal kyphoscoliosis were examined. All patients underwent OLIF surgery (using a cage and bone graft from the iliac crest) with open pedicle screws or percutaneous pedicle screws, without real-time monitoring by electromyography. Visual analog scale score and Oswestry disability index were evaluated before and 12 months after surgery, and fusion rate at OLIF cage, correction of the deformity, total blood loss, and surgical complications were also evaluated. Results Pain scores significantly improved after surgery (p<0.05). Fusion rate was found to be 90%, balance parameters also improved after surgery (p<0.05), and average total blood loss was less than 350 mL. There was no spinal nerve, major vessel, peritoneal, or urinary injury, or breakage of instrumentation. Conclusions OLIF surgery for degenerated lumbar spinal kyphoscoliosis is less invasive than other procedures and good surgical results were produced without major complications.

Lumbar disc degeneration induces persistent groin pain.

Study Design. Prospective study of 212 patients with groin pain but without low back pain. Objective. To evaluate discogenic groin pain without low back pain or radicular pain. Summary of Background Data. Patients feel low back pain originating from discogenic disease. It has been reported that the rat lower lumbar discs are innervated mainly by L2 dorsal root ganglion neurons. Thus, it is possible that patients feel referred groin pain corresponding to the L2 dermatome originating from intervertebral discs; however, the referred pain has not been fully clarified in humans. Methods. We selected 5 patients with groin pain alone for investigation. The patients suffered from groin pain and showed disc degeneration only at 1 level (L4-L5 or L5-S1) on magnetic resonance imaging. Patients did not show any hip joint abnormality on radiography or magnetic resonance imaging. To prove that their groin pain originated in degenerated intervertebral discs, we evaluated changes in groin pain after infiltration of lidocaine into hip joints and examined pain provocation on discography, pain relief by anesthetic discoblock, and finally anterior lumbar interbody fusion surgery. Results. All patients were negative for hip joint block, positive for pain provocation on discography, and positive for pain relief by anesthetic discoblock. Furthermore, bony union was achieved 1 year after anterior interbody fusion surgery in all patients, and visual analogue scale score of groin pain was significantly improved at 1 year after surgery in all patients (P < 0.05). Conclusion. In the current study, we diagnosed discogenic groin pain, using magnetic resonance imaging, infiltration of lidocaine into the hip joint, pain provocation on discography, pain relief by anesthetic discoblock, and lumbar surgery. It is important to consider the existence of discogenic groin pain if patients do not show low back pain.