Taito Itabashi

Axial symptoms after cervical laminoplasty with C3 laminectomy compared with conventional C3-C7 laminoplasty: a modified laminoplasty preserving the semispinalis cervicis inserted into axis.

Study Design. Results of C4–C7 laminoplasty with C3 laminectomy and C3–C7 laminoplasty were compared. Objectives. To clarify prospectively whether the modified laminoplasty preserving the semispinalis cervicis inserted into C2 could reduce the axial symptoms compared with conventional laminoplasty reattaching the muscle to C2. Summary of Background Data. Intraoperative damage of the semispinalis cervicis is relevant to the development of axial symptoms after laminoplasty. In C3–C7 laminoplasty, however, it is difficult to preserve the muscle insertion into C2 while opening the C3 lamina. Methods. The axial symptoms of 40 patients (Group A) with C4–C7 laminoplasty with C3 laminectomy were compared with those of 16 patients (Group B) with C3–C7 laminoplasty. The cross-sectional areas of the cervical posterior muscles were measured on magnetic resonance images. Results. The number of patients with no postoperative axial symptoms increased (P = 0.035) from 19% to 52.5%, and the number of patients whose symptoms worsened after surgery decreased (P = 0.020) from 50% to 17.5%. The average atrophy rate of cross-sectional area was smaller (P < 0.001) in Group A (2.4%) than in Group B (10.8%). Conclusions. This method was less invasive to the cervical posterior muscles than C3–C7 laminoplasty. This is an effective procedure for preventing postoperative axial symptoms.

Anatomic study of the semispinalis cervicis for reattachment during laminoplasty

Some patients who had cervical laminoplasty with subsequent substantial loss of cervical lordosis have shown failed healing of a repaired semispinalis cervicis. We also have identified some patients in whom it is difficult to repair the C2 spinous process during laminoplasty. We therefore quantitatively analyzed the morphologic features of the C2 insertion of the semispinalis cervicis and obtained data relevant to the repair of the muscle. In 24 cadavers, the width and height of the semispinalis cervicis insertion in C2 and the length and opening angle of the C2 spinous process were measured. We observed considerable individual variations in the morphologic features of the C2 spinous process and the C2 insertion of the semispinalis cervicis. The opening angle of the C2 spinous process was smaller in males than in females. In most of the cases, the width of the insertion was narrower than the width of the spinous process spacers that commonly are used in laminoplasty. Preoperative prediction of the morphologic features of insertion at the original site is possible by measuring the opening angle of the C2 spinous process using three-dimensional computed tomography because the muscle insertion correlated with the angle of the C2 spinous process. This information may be useful in reattaching the semispinalis cervicis during cervical laminoplasty.

Structural Varieties of Small Proteoglycans in Human Spinal Ligament

Three types of small proteoglycan were purified from human spinal ligaments by ultracentrif-ugation, ion-exchange chromatography, gel-chromatography, and hydrophobic chromatogra-phy. Two of them were identified as decorin and biglycan, and the other was thought to be a decorin-subtype. Molecular sizes of decorin and decorin-subtype were both 85 kDa, and that of biglycan was 200 kDa. N-Terminal amino acid sequence of decorin-subtype corresponded with that of decorin, although it was different from decorin in terms of composition of amino acids and glycosaminoglycan chains, and reactivity with anti-human decorin antibody. The ratios of chondroitin sulfate to dermatan sulfate contained in the three proteoglycans were different, and the location of that in glycosaminoglycan chains was also thought to be different. It was demonstrated that three types of proteoglycan which are structurally different are present in extracellular matrix.

K-line (-) in the Neck-Flexed Position in Patients With Ossification of the Posterior Longitudinal Ligament Is a Risk Factor for Poor Clinical Outcome After Cervical Laminoplasty.

Study Design. Retrospective study comparing postoperative clinical outcomes after cervical laminoplasty between K-line (–) ossification of the posterior longitudinal ligament (OPLL) and K-line (+) OPLL in the neck-flexed position. Objective. To investigate postoperative outcomes using Japanese Orthopedic Association (JOA) scores, and grip-and-release (GR) and foot-tap (FT) test scores after laminoplasty in patients with K-line (–) OPLL in the neck-flexed position. Summary of Background Data. Cervical laminoplasty has been reported to lead to poor outcomes in K-line (–) OPLL and good outcomes in K-line (+) OPLL. The cervical spine, however, continues moving in the extension and flexion direction after laminoplasty. Methods. Patients with cervical myelopathy were divided into K-line (+) and (–) in the neck-flexed position. We compared postoperative outcomes after cervical laminoplasty using recovery rate, as assessed by the JOA score and degree of improvement in the six JOA score items, and performance, as assessed by GR and (FT) tests, between patients with K-line (+) OPLL (n = 18) and K-line (–) OPLL (n = 23) in the neck-flexed position. Results. Recovery rate of JOA score (23.8%) of patients in the K-line (–) group was significantly lower (P = 0.028) than that (46.3%) of K-line (+) group in the neck-flexed position. In the K-line (+) group, significant improvements were seen in all JOA-score items except bladder function; however, in the K-line (–) group, improvements were seen only in upper- and the lower-extremity sensory functions. In the K-line (+) group, mean GR and FT tests significantly improved, but in the K-line (–) group, only mean FT test significantly improved. Conclusion. The K-line (–) OPLL in the neck-flexed position is a risk factor for poor clinical outcome after cervical laminoplasty. Level of Evidence: 4

Interaction Between Proteoglycans and α-Elastin in Construction of Extracellular Matrix of Human Yellow Ligament

One type of large proteoglycan and three types of small proteoglycans (decorin, decorin-subtype, and biglycan) were purified by chromatography, and α-elastin was isolated by alkali treatment from human yellow ligaments taken at the time of operation. The interaction of the proteoglycans with immobilized α-elastin on a sensor was analyzed by surface plasmon resonance, and we confirmed that each of the small proteoglycans exhibited a specific binding to α-elastin. The binding sites of small proteoglycans were contained in the protein cores. In addition, the differences in the interaction of the small proteoglycans with α-elastin of normal and ossified ligaments were compared. The interactions of the small proteoglycans with α-elastin of the ossified ligaments were lower than those with α-elastin of the normal ligaments. In the ossified ligaments, neodesmosine, one of the cross-linking amino acids, was significantly less than in the normal ligaments (p < .05).

Bactericidal and antimicrobial effects of pure titanium and titanium alloy treated with short-term, low-energy UV irradiation

OBJECTIVES The surface of pure titanium (Ti) shows decreased histocompatibility over time; this phenomenon is known as biological ageing. UV irradiation enables the reversal of biological ageing through photofunctionalisation, a physicochemical alteration of the titanium surface. Ti implants are sterilised by UV irradiation in dental surgery. However, orthopaedic biomaterials are usually composed of the alloy Ti6Al4V, for which the antibacterial effects of UV irradiation are unconfirmed. Here we evaluated the bactericidal and antimicrobial effects of treating Ti and Ti6Al4V with UV irradiation of a lower and briefer dose than previously reported, for applications in implant surgery. MATERIALS AND METHODS Ti and Ti6Al4V disks were prepared. To evaluate the bactericidal effect of UV irradiation, Staphylococcus aureus 834 suspension was seeded onto the disks, which were then exposed to UV light for 15 minutes at a dose of 9 J/cm2. To evaluate the antimicrobial activity of UV irradiation, bacterial suspensions were seeded onto the disks 0, 0.5, one, six, 24 and 48 hours, and three and seven days after UV irradiation as described above. In both experiments, the bacteria were then harvested, cultured, and the number of colonies were counted. RESULTS No colonies were observed when UV irradiation was performed after the bacteria were added to the disks. When the bacteria were seeded after UV irradiation, the amount of surviving bacteria on the Ti and Ti6Al4V disks decreased at 0 hours and then gradually increased. However, the antimicrobial activity was maintained for seven days after UV irradiation. CONCLUSION Antimicrobial activity was induced for seven days after UV irradiation on both types of disk. Irradiated Ti6Al4V and Ti had similar antimicrobial properties.Cite this article: T. Itabashi, K. Narita, A. Ono, K. Wada, T. Tanaka, G. Kumagai, R. Yamauchi, A. Nakane, Y. Ishibashi. Bactericidal and antimicrobial effects of pure titanium and titanium alloy treated with short-term, low-energy UV irradiation. Bone Joint Res 2017;6:108-112. DOI: 10.1302/2046-3758.62.2000619.

Percutaneous ultrasonographic evaluation of the spinal cord after cervical laminoplasty.

Study Design. Prospective cohort study. Objective. To investigate the dynamic changes of cervical spinal cord with postural change after cervical laminoplasty by means of postoperative percutaneous ultrasonography. Summary of Background Data. Many reports have been published about intraoperative ultrasonographic evaluation of the spinal cord. Few reports have described postoperative diagnostic ultrasonographic findings of the spinal cord after a previous laminectomy. To date, there are no studies that have examined the changes in pulsation pattern and intensity of the spinal cord at different body positions with percutaneous ultrasonography. Methods. Thirty-three patients after cervical laminoplasty were evaluated postoperatively by percutaneous ultrasonography of the cervical spinal cord. Ultrasonographic images were obtained from 5 different body positions sitting with neck neutral, sitting with neck flexion, sitting with neck extension, prone, and supine position. Results. The pattern and intensity of cervical spinal cord pulsation and the anteroposterior position of the cervical spinal cord changed according to posture. Pulsation of the cervical spinal cord was more common in sitting position, whereas wave motion was more common in supine position. Supine, prone, sitting with neck extension, sitting with neck neutral, and sitting with neck flexion position were ranked in descending order of spinal cord pulsating intensity. Subarachnoidal space ventral to the cervical spinal cord was more likely to appear in the supine position. Conclusion. Assuming that good spinal cord pulsation represents good spinal circulation, these results suggest that the supine position will provide the most favorable condition for recovery of the cervical spinal cord. Level of Evidence: 2

A novel posterior approach preserving three muscles inserted at C2 in multilevel cervical posterior decompression and fusion using C2 pedicle screws

PurposeTo present a novel posterior approach in multilevel cervical posterior decompression and fusion (PDF) using C2 pedicle screws that preserves the rectus capitis posterior major, oblique capitis inferior, and semispinalis cervicis.MethodsWe analyzed 30 consecutive patients who underwent C2–T1 PDF using an approach that preserved these three muscles without resecting. We assessed O-C2 range of motion (ROM), cross-sectional area of the cervical posterior muscles, rotational ROM, visual analog scale (VAS) for axial pain, neck disability index (NDI), and limitations of activities of daily living (ADL) involving neck movements.ResultsMean preoperative O-C2 ROM (23.6°) was significantly increased postoperatively (33.0°). Mean atrophy rate of the cross-sectional area was 3.9%. Postoperatively, 69.8% of the preoperative rotational ROM (113.3°) was retained. The preoperative VAS for axial pain and the NDI did not increase postoperatively. The postoperative O-C2 ROM (33.9°) in 26 patients for whom extension ADL were possible was significantly larger than that in four patients for whom extension ADL were impossible (26.9°). The postoperative retained rate of rotational ROM (75.8%) in 18 patients for whom rotation ADL were possible was significantly larger than that in 12 patients for whom rotation ADL were impossible (62.3%).ConclusionsThis is potentially an effective approach for maintaining O-C2 ROM and rotational ROM, which enabled good levels of ADL after C2–T1 PDF. Axial pain and NDI were not worse after PDF.

Photofunctionalised Ti6Al4V implants enhance early phase osseointegration

Objectives Ultraviolet (UV) light-mediated photofunctionalisation is known to improve osseointegration of pure titanium (Ti). However, histological examination of titanium alloy (Ti6Al4V), which is frequently applied in orthopaedic and dental surgery, has not yet been performed. This study examined the osseointegration of photofunctionalised Ti6Al4V implants. Methods Ti and Ti6Al4V implants were treated with UV light, and the chemical composition and contact angle on the surfaces were evaluated to confirm photofunctionalisation. The implants were inserted into femurs in rats, and the rats were killed two or four weeks after the surgery. For histomorphometric analysis, both the bone–implant contact (BIC) ratio and the bone volume (BV) ratio were calculated from histological analysis and microcomputed tomography data. Results The amount of carbon and the contact angle on both implants were significantly reduced after UV irradiation. The BIC ratios for both UV light-treated implants significantly increased at two weeks, but there was no significant difference at four weeks. There was no significant difference in the BV ratios between the UV light-treated and control implants at two or four weeks. Conclusions This study suggests that photofunctionalisation of Ti6Al4V implants, similar to that of Ti implants, may promotes osseointegration in early but not in the late phase of osseointegration. Cite this article: R. Yamauchi, T. Itabashi, K. Wada, T. Tanaka, G. Kumagai, Y. Ishibashi. Photofunctionalised Ti6Al4V implants enhance early phase osseointegration. Bone Joint Res 2017;6:331–336. DOI: 10.1302/2046-3758.65.BJR-2016-0221.R1.

The role of proteoglycans in ossification of spinal ligaments

Abstract Proteoglycans (PGs) are considered to have important functions that influence the properties of the extracellular matrix. In this study, PGs were purified from human yellow ligaments by ion-exchange and gel-filtration chromatography. Age-related changes in PG and glycosaminoglycan (GAG) chains were studied using specimens obtained from patients divided into four age groups. Small PGs were present in similar amounts in all groups. Conversely, large PGs increased with aging. GAG in large PGs mainly consisted of chondroitin 6-sulfate (Ch6S), whereas in small PGs, it mainly consisted of dermatan sulfate (DS), although the ratio of Ch6S increased with aging. The major components of GAG chains in normal and ossified yellow ligaments were DS and ChS, respectively. Also, the affinity of high-performance liquid chromatography (HPLC) on hydroxyapatite columns showed that DS chains bound to the hydroxyapatite more strongly than ChS chains. These results indicate that the change from DS to ChS is important in age-related changes and ossification of the ligaments, because ChS chains, which have a lower affinity for hydroxyapatite, might contribute to facilitation of the crystallization of hydroxyapatite.