Toshihiko Sakakibara

Porosity of β-tricalcium phosphate affects the results of lumbar posterolateral fusion.

Study Design: Clinical case-control and cross-sectional study. Objectives: To determine the influence of different porosities of &bgr;-tricalcium phosphate (&bgr;-TCP) as a bone substitute combined with local autograft bone obtained from decompression for lumbar posterolateral fusion (PLF). Summary of Background Data: Several reports have documented a high bone fusion rate using &bgr;-TCP as a bone substitute. &bgr;-TCP is increasingly used to supplement autograft in lumbar PLF, but the influence of different porosities of &bgr;-TCP for the lumbar PLF has not been reported. Methods: Sixty patients who were diagnosed with lumbar degenerative diseases and treated with 2-level noninstrumented lumbar PLF were divided into 2 groups. Thirty patients were treated with 75% porous &bgr;-TCP (&bgr;-TCP-75 group), and the others were treated with 60% porous &bgr;-TCP (&bgr;-TCP-60 group). The clinical and radiographic results of each patient were assessed at 2 years postoperatively. Results: Both the groups showed a good improvement rate of the Japanese Orthopaedic Association score (JOA score) at 2 years postoperatively, but there were no significant differences between them. The &bgr;-TCP-75 group represented a bone fusion rate of 70.0% (64.7% in men, 76.9% in women) and the &bgr;-TCP-60 group was 93.3% (87.5% in men, 100.0% in women). The latter exhibited a significantly better bone fusion rate than the &bgr;-TCP-75 group (P<0.05). Conclusions: In lumbar PLF, 60% porous &bgr;-TCP granules achieved a higher bone fusion rate than 75% porous &bgr;-TCP granules.

Prevalence and countermeasures for venous thromboembolic diseases associated with spinal surgery: a follow-up study of an institutional protocol in 209 patients.

Study Design. A prospective study of 209 patients undergoing spinal surgery. Objective. To determine the incidence of venous thromboembolic diseases, including deep venous thrombosis (DVT) and pulmonary embolism (PE), and to evaluate the effectiveness of an institutional protocol for venous thromboembolic diseases during the spinal surgery perioperative period. Summary of Background Data. Although patients undergoing spinal surgery are at risk of venous thromboembolism (VTE), there are no universally accepted guidelines for VTE prophylaxis. Methods. Between December 2006 and January 2011, 209 patients undergoing spinal surgery (121 males, 88 females; average age: 64 yr), who also had ultrasonographic assessments of both legs before and after surgery, were prospectively assessed. A pneumatic sequential compression device and standard compression stockings were used for primary VTE prophylaxis. In Mie University Hospital protocol, pharmacological agents were not used for VTE prophylaxis after surgery. However, when a distal type DVT was found preoperatively, an anticoagulant medication was administered until 6 hours prior to surgery. After detection of DVTs, weekly ultrasonography assessed the DVT. Results. Twenty-three patients (11.0%) showed VTE in the spinal surgery perioperative period. Nine patients (4.3%) had VTE (PE with proximal DVT, 1 [0.5%]; distal DVT, 8 [3.8%]) before surgery. In the one case of asymptomatic PE with proximal DVT, an inferior vena cava filter was placed before surgery. Fourteen patients (6.7%) developed new-onset VTE (PE with proximal DVT, 2 [1.0%]; distal DVT, 12 [5.9%]) after spinal surgery. New-onset PE with proximal DVT occurred in 2 patients after surgery. Follow-up ultrasonographic assessment showed that the DVT disappeared completely in 85% (17/20) of patients with a distal type DVT during the perioperative period. Conclusion. DVT assessment using ultrasonography is important for proper management of VTE during the perioperative period of spinal surgery, especially for high-risk patients, such as those with advanced age or neurological deficit. The institutional protocol for VTE using pneumatic sequential compression device and compression stockings is effective, although the administration of chemoprophylaxis should be considered for high-risk patients, such as those with spinal tumors and spinal trauma. Level of Evidence: 3

A biomechanical comparison between cortical bone trajectory fixation and pedicle screw fixation

PurposeThere have been several reports on the pullout strength of cortical bone trajectory (CBT) screws, but only one study has reviewed the stability of functional spine units using the CBT method. The purpose of this study was to compare vertebral stability after CBT fixation with that after pedicle screw (PS) fixation.MethodsIn this study, 20 lumbar spine (L5–6) specimens were assigned to two groups: the CBT model group that underwent CBT screw fixation (n = 10) and the PS model group that underwent pedicle screw fixation (n = 10). Using a six-axis material testing machine, bend and rotation tests were conducted on each model. The angular displacement from the time of no load to the time of maximum torque was defined as range of motion (ROM), and then, the mean ROM in the bend and rotation tests and the mean rate of relative change of ROM in both the bend and rotation tests were compared between the CBT and PS groups.ResultsThere were no significant differences between the CBT and PS groups with regard to the mean ROMs and the mean rate of relative change of ROMs in both the bend and rotation tests.ConclusionIntervertebral stability after CBT fixation was similar to that after PS fixation.

Direction of the formation of anterior lumbar vertebral osteophytes

BackgroundX-ray images of lumbar degenerative diseases often show not only claw osteophytes, but also pairs of osteophytes that form in a direction away from the adjacent disc. We have investigated the direction of the formation of anterior lumbar vertebral osteophytes across the lumbar vertebrae using a sufficient number of lumbar radiographs, because osteophytes images can provide essential information that will contribute to the understanding of the pathology and progress of lumbar spine degeneration.MethodsThe direction of the formation of 14,250 pairs of anterior lumbar vertebral osteophytes across the adjacent intervertebral discs in 2,850 patients who were all over 60 years old was investigated. Anterior lumbar vertebral osteophytes were distributed into six groups based on the direction of extension of each pair of osteophytes across the intervertebral disc space.ResultsIn L1–L2 and L2–L3, the number of patients classified into groups B (the pair of osteophytes extended in the direction of the adjacent disc) and C (almost complete bone bridge formation by a pair of osteophytes across the intervertebral disc space) was larger than that classified into group D (the pair of osteophytes extended in a direction away from the adjacent disc). In L3–L4, L4–L5 and L5-S1, the number of patients in group D was greater than that of patients belonging to groups B and C.ConclusionOur study showed that pairs of osteophytes frequently formed in the direction of the adjacent disc in the upper lumbar vertebrae (L1–L2 and L2–L3) and in the direction away from the adjacent disc in middle or lower lumbar vertebrae (L3–L4, L4–L5, and L5-S1).

Are Deer and Boar Spines a Valid Biomechanical Model for Human Spines

Objective: To examine the validity of using cadaveric spines of deer or boars for biomechanical experiments as substitutes for the cadaveric spine of humans. Materials and Methods: Five specimens of the L3-4 functional spinal unit of human cadavers, mature deer and mature boars were prepared according to 3 models: 1) normal model, 2) injured model and 3) pedicle screw fixation model and they were evaluated in 8-direction bending and 2-direction rotation tests. The mean ROM in bending and rotation tests of each specimen and the rate of relative change of ROM were calculated. Results: Flexibility of cadaveric spine of deer and boars was slightly higher than that of cadaveric spine of humans in the bending and rotation tests, but the rates of relative change of ROM in the rotational and bending tests were similar across species. Conclusions: It is reasonable to use cadaveric spines of deer and boars as a model of the human cadaveric spine in biomechanical experiments.

Intradiscal Injection of Autologous Platelet-Rich Plasma Releasate to Treat Discogenic Low Back Pain: A Preliminary Clinical Trial.

Study Design Preliminary clinical trial. Purpose To determine the safety and initial efficacy of intradiscal injection of autologous platelet-rich plasma (PRP) releasate in patients with discogenic low back pain. Overview of Literature PRP, which is comprised of autologous growth factors and cytokines, has been widely used in the clinical setting for tissue regeneration and repair. PRP has been shown in vitro and in vivo to potentially stimulate intervertebral disc matrix metabolism. Methods Inclusion criteria for this study included chronic low back pain without leg pain for more than 3 months; one or more lumbar discs (L3/L4 to L5/S1) with evidence of degeneration, as indicated via magnetic resonance imaging (MRI); and at least one symptomatic disc, confirmed using standardized provocative discography. PRP releasate, isolated from clotted PRP, was injected into the center of the nucleus pulposus. Outcome measures included the use of a visual analog scale (VAS) and the Roland-Morris Disability Questionnaire (RDQ), as well as X-ray and MRI (T2-quantification). Results Data were analyzed from 14 patients (8 men and 6 women; mean age, 33.8 years). The average follow-up period was 10 months. Following treatment, no patient experienced adverse events or significant narrowing of disc height. The mean pain scores before treatment (VAS, 7.5±1.3; RDQ, 12.6±4.1) were significantly decreased at one month, and this was generally sustained throughout the observation period (6 months after treatment: VAS, 3.2±2.4, RDQ; 3.6±4.5 and 12 months: VAS, 2.9±2.8; RDQ, 2.8±3.9; p<0.01, respectively). The mean T2 values did not significantly change after treatment. Conclusions We demonstrated that intradiscal injection of autologous PRP releasate in patients with low back pain was safe, with no adverse events observed during follow-up. Future randomized controlled clinical studies should be performed to systematically evaluate the effects of this therapy.

Traumatic lumbosacral spondyloptosis treated five months after injury occurrence: a case report.

Study Design. A case report. Objective. To describe a case of traumatic lumbosacral spondyloptosis and present a literature review. Summary of Background Data. Traumatic spondyloptosis is a very rare injury caused by high-energy trauma. Eight cases of traumatic spondyloptosis of L5–S1 have been reported, including only 1 case treated 8.5 months after injury occurrence. Methods. A 45-year-old Myanmar male experienced severe lower back pain and paresis of the lower extremities after a landslide disaster. Plain radiographs showed spondyloptosis, with the 5th lumbar vertebra located anterior to the 1st sacral vertebra. Computed tomography myelography demonstrated complete bilateral pars interarticularis fracture dislocation at L5–S1 and a complete block between L5 and S1 with apparent spondyloptosis. Neurological function of this patient improved after conservative treatment for 5 months; however, his severe lower back pain persisted. Thus, surgery for in situ posterior decompression and fusion of L3–S1 was performed. Results. Lower back pain of the patient had nearly disappeared 2 weeks after surgery, and he was able to walk for more than 1 hour without assistance 2 years after surgery. Conclusion. We performed posterior decompression and in situ fusion of L3–S1 for the patients with traumatic lumbosacral spondyloptosis treated 5 months after injury, and the surgery produced a favorable clinical outcome.

Adult Traumatic Atlantoaxial Rotatory Fixation: A Case Report

We presented a very rare case of adult Fielding type I atlantoaxial rotatory fixation (AARF). We performed awake manual reduction of the dislocation without need for anesthesia, achieving excellent outcomes, and no previous reports have described awake reduction without the need for anesthesia. AARF in this case was attributed to excessive extension and rotation forces applied to the cervical spine. For the management of adult Fielding type I AARF, early diagnosis and early reduction may lead to excellent outcomes.

Relationship between brassiere cup size and shoulder-neck pain in women.

There are very few reports in regard to relationship between breast size and shoulder-neck pain. The purpose of this study is to examine the correlations among breast size, brassiere cup size, and moment-in-time reporting of shoulderneck pain in a group of adult women. Three hundred thirty nine female volunteers from the hospital staff answered the questionnaire. Breast size, brassiere cup size, and shoulder-neck pain were self-reported by each participant. The relationship among breast size, brassiere cup size and shoulder-neck pain was investigated. Spearman’s test showed no significant relationship between shoulder-neck pain and brassiere cup size. However, after participants were classified into two groups (small brassiere cup size and large brassiere cup size with 219 and 120 participants, respectively), there was a significant positive correlation between shoulder-neck pain and large brassiere cup size (p<0.05). There was no significant relationship between shoulder-neck pain and breast size. In conclusion, large brassiere cup size is an important cause of shoulder-neck pain.

Expression of Proteinase-Activated Receptor-2 in the Intervertebral Disc

Study Design. Immunohistochemical and biochemical analyses of proteinase-activated receptor-2 (PAR-2) in rat and human intervertebral discs (IVDs). Objectives. To examine the expression and function of PAR-2 in rat IVD cells, and to determine if PAR-2 is expressed in human IVDs. Summary of Background Data. PAR-2 is a G protein-coupled receptor that contributes to the regulation of inflammatory reactions and the pathophysiology of inflammatory diseases, including arthritis. The expression of PAR-2 in the IVD has not been determined. Methods. PAR-2 expression by rat IVD cells and tissues was examined using immunohistochemistry and western blot. Rat anulus fibrosus cells in monolayer culture were used to examine the biologic role of PAR-2 in vitro. The effect of PAR-2–activating peptide (PAR-2AP) on the catabolic cascade was assessed by western blot and real-time PCR. The expression of PAR-2 by human IVD tissues at different stages of degeneration was determined by immunohistochemical analyses. Results. PAR-2 was expressed by rat IVD cells and in both anulus fibrosus and nucleus pulposus tissues, PAR-2 expression was up-regulated by interleukin-1&bgr; (IL-1&bgr;). PAR-2AP significantly increased the release of IL-1&bgr; into the medium. Although PAR-2AP had no direct effect on matrix metalloproteinase-3 (MMP-3) and MMP-13 mRNA levels, treatment with PAR-2AP significantly up-regulated the mRNA levels of a disintegrin and metalloproteinase with thrombospondin motif–4. The simultaneous administration of PAR-2AP and IL-1&bgr; synergistically up-regulated the mRNA levels of a disintegrin and metalloproteinase with thrombospondin motif–4, MMP-3, and MMP-13. The expression of PAR-2 was identified in human IVD tissues. The number of PAR-2–expressing cells was significantly elevated in advanced stages of IVD degeneration compared with those in early stages of degeneration. Conclusion. Our results demonstrate for the first time that IVD cells express PAR-2. The expression of PAR-2 is regulated by IL-1&bgr; stimulation. PAR-2 activation accelerates the expression of matrix-degrading enzymes. PAR-2 may play an important role in the cytokine-mediated catabolic cascade and consequently may be involved in IVD degeneration.