Wataru Saito

Teriparatide increases the insertional torque of pedicle screws during fusion surgery in patients with postmenopausal osteoporosis

OBJECT The object of this study was to examine the efficacy of preoperative teriparatide treatment for increasing the insertional torque of pedicle screws during fusion surgery in postmenopausal women with osteoporosis. METHODS Fusion surgery for the thoracic and/or lumbar spine was performed in 29 postmenopausal women with osteoporosis aged 65-82 years (mean 72.2 years). The patients were divided into 2 groups based on whether they were treated with teriparatide (n = 13) or not (n = 16) before the surgery. In the teriparatide-treated group, patients received preoperative teriparatide therapy as either a daily (20 μg/day, n = 7) or a weekly (56.5 μg/week, n = 6) injection for a mean of 61.4 days and a minimum of 31 days. During surgery, the insertional torque was measured in 212 screws inserted from T-7 to L-5 and compared between the 2 groups. The correlation between the insertional torque and the duration of preoperative teriparatide treatment was also investigated. RESULTS The mean insertional torque value in the teriparatide group was 1.28 ± 0.42 Nm, which was significantly higher than in the control group (1.08 ± 0.52 Nm, p < 0.01). There was no significant difference between the daily and the weekly teriparatide groups with respect to mean insertional torque value (1.34 ± 0.50 Nm and 1.18 ± 0.43 Nm, respectively, p = 0.07). There was negligible correlation between insertional torque and duration of preoperative teriparatide treatment (r(2) = 0.05, p < 0.01). CONCLUSIONS Teriparatide injections beginning at least 1 month prior to surgery were effective in increasing the insertional torque of pedicle screws during surgery in patients with postmenopausal osteoporosis. Preoperative teriparatide treatment might be an option for maximizing the purchase of the pedicle screws to the bone at the time of fusion surgery.

Acceleration of bone formation during fracture healing by injectable collagen powder and human basic fibroblast growth factor containing a collagen‐binding domain from Clostridium histolyticum collagenase

Growth factor delivered with implantable biomaterials has been used to both accelerate and ensure healing of open fractures in human patients. However, a major limitation of implantable biomaterials is the requirement for open surgical placement. Here, we developed an injectable collagen material-based bone formation system consisting of injectable collagen powder with fibril morphology and collagen triple helix conformation, and basic fibroblast growth factor (bFGF) fused to the collagen-binding domain (CBD) of Clostridium histolyticum collagenase. The affinity of the CBD towards collagen was confirmed by the results of collagen-binding assays. Moreover, the combination of the collagen binding-bFGF fusion protein (CB-bFGF) with injectable collagen powder induced bone formation at protein concentrations lower than those required for bFGF alone in mice fracture models. Taken together, these properties suggest that the CB-bFGF/collagen powder composite is a promising injectable material for bone repair in the clinical setting.

Triclosan-coated sutures reduce wound infections after spinal surgery: a retrospective, nonrandomized, clinical study.

BACKGROUND CONTEXT Surgical site infection (SSI) is a serious postoperative complication. The incidence of SSIs is lower in clean orthopedic surgery than in other fields, but it is higher after spinal surgery, reaching 4.15% in high-risk patients. Several studies reported that triclosan-coated polyglactin 910 sutures (Vicryl Plus; Ethicon, Inc., Somerville, NJ, USA) significantly reduced the infection rate in the general surgical, neurosurgical, and thoracic surgical fields. However, there have been no studies on the effects of such coated sutures on the incidence of SSIs in orthopedics. PURPOSE To compare the incidence of wound infections after spinal surgery using triclosan-coated suture materials with that of noncoated ones. STUDY DESIGN/SETTING A retrospective, nonrandomized, and clinical study. PATIENT SAMPLE From May 2010 to April 2012, 405 patients underwent a spinal surgical procedure in the Department of Orthopedic Surgery of two university hospitals. OUTCOME MEASURES The primary outcome was the number of wound infections and dehiscences. METHODS Two hundred five patients had a conventional wound closure with polyglactin 910 suture (Vicryl) between May 2010 and April 2011 (Time Period 1 [TP1]), and 200 patients underwent wound closure with triclosan-coated polyglactin 910 suture (Vicryl Plus) between May 2011 and April 2012 (TP2). Statistical comparisons of wound infections, dehiscence, and risk factors for poor wound healing or infection were performed. None of the authors has any conflict of interest associated with this study. RESULTS There were two cases of wound dehiscence in TP1 and one in TP2 (p=.509). Using noncoated sutures in TP1, eight patients (3.90%) had wound infections, whereas one patient (0.50%) had wound infections in TP2 (using triclosan-coated sutures); the difference was significant (p=.020). CONCLUSIONS The use of triclosan-coated polyglactin 910 sutures instead of polyglactin 910 sutures may reduce the number of wound infections after spinal surgery.

Surgical correction of spinal deformity in patients with congenital muscular dystrophy

BackgroundCongenital muscular dystrophy (CMD), among the myopathic disorders is one form of flaccid neuromuscular disorder (NMD). Patients with NMD frequently develop progressive spinal deformity. For NMD patients who have a severe spinal deformity, sitting is often difficult and is accompanied by pain and breakdown of the skin. Spinal deformity surgery in these patients has been highly effective in stabilizing the spine, maintaining upright, comfortable sitting balance, and improving patients’ quality of life. However, many studies have reported significant rates of peri/postoperative complications in these patients. To our knowledge, there has been no study on the results of spinal deformity surgery in patients with CMD. The purpose of this study was to review the clinical and radiological results of spinal deformity surgery in this group of patients with CMD.MethodsBetween 2004 and 2007, a total of 10 CMD patients underwent scoliosis surgery. There were three patients with Fukuyama CMD, three with Ullrich CMD, and 4 with nonsyndromic CMD (merosin-negative). They were nonambulatory. All the patients had standard posterior spinal fusion and pedicle-screw-alone fixation from T3 or T4 to L5 for spinal deformity. Our inclusion criteria required that each patient (1) had considerable difficulty with sitting balance and pain or breakdown of the skin due to scoliosis; (2) was able to ventilate his or her lung autonomously; (3) was not ventilator-dependent; and (4) did not have cardiac failure. Sufficient informed consent was important, and the decision to perform surgery was made by the patient/family with sufficient preoperative informed consent. Patients were trained with inspiratory muscle training (IMT) using an inspiratory muscle trainer (Threshold IMT) for 6 weeks prior to surgery Cardiac function was assessed preoperatively. Pulmonary function tests were performed preoperatively and postoperatively. Radiographic assessments were performed on sitting anteroposterior (AP) and lateral radiographs. These assessments were made periodically. The Cobb angles of the curves and spinal pelvic obliquity (SPO) on the coronal plane, thoracic kyphosis, and lumbar lordosis were measured. The preoperative AP radiograph and side-bending films were examined to determine flexibility. Patients’ and parents’ satisfaction were surveyed by a self-completed questionnaire at the last follow-up.ResultsPercent forced vital capacity (%FVC) increased from a mean of 30% before IMT to a mean of 34% the day before surgery. The preoperative scoliosis was 75° (range 61°–95°). The scoliotic curvature on preoperative side-bending films was 19° (range 11°–28°). All patients were extubated on the day of surgery. No patients developed cardiac or respiratory complications. The scoliotic curvature was 18° (range 10°–25°) immediately after surgery, and 19° (range 12°–27°) at the last follow-up. The pelvic obliquity improved from a mean of 17° (range 14°–20°) preoperatively to a mean of 6° (range 4°–9°) postoperatively and to 7° (range 4°–10°) at the last follow-up. Balanced sitting posture was achieved and maintained. On the sagittal plane, good reconstruction of sagittal plane alignment was recreated and maintained. There were no major complications or deaths. All patients/parents completed the outcome satisfaction questionnaire. Eight patients/parents were very satisfied and two were satisfied.ConclusionsPedicle-screw-alone fixation and fusion to L5 was safe and effective in CMD patients with scoliosis of <95° and pelvic obliquity of <20°. Scoliosis curves were flexible (75% correction) on side-bending films preoperatively. Curve correction and maintenance of correction in the coronal and sagittal plane was excellent. The pelvic obliquity significantly improved. Balanced sitting posture was achieved and maintained in all patients. Our patients with CMD spinal deformity and a moderately and severely decreased FVC could be operated on safely and successfully with general anesthesia. All patients were extubated in the operating room. There were no major complications or deaths. We believe a FVC of <30% alone is not a predisposition to pulmonary complications. However, cardiomyopathy might be a determining risk of mortality, and we believe surgery for these patients should be avoided. Patients’ and parents’ satisfaction was high.

Should we use cortical bone screws for cortical bone trajectory

OBJECT In 2009, Santoni et al. reported cortical bone trajectory (CBT) as a method of inserting pedicle screws to obtain more solid fixation, and proposed the use of cortical trajectory screws with a more closely placed thread (cortical screws) for CBT. Since the entry trajectory in CBT differs from that in the traditional trajectory, it is unclear whether the increased strength derives from the specific trajectory or the shape of the screw thread in contact with the cortical bone. Whether the use of cortical screws is always required with CBT thus remains unclear. The authors therefore investigated the relationship between screw entry trajectory and screw thread characteristics and pullout strength in animal experiments. METHODS Lumbar vertebrae (L1-L4) from 4-month-old female pigs were randomly assigned to one of 4 groups, with cancellous screws or cortical screws inserted via the traditional trajectory or CBT. For pullout strength testing, the screw was pulled out vertically against the direction of insertion. Rod pullout testing (toggle testing) was also performed, and the peak breaking strength was measured. RESULTS The maximum pullout strength was significantly greater for CBT using cortical screws than for the traditional trajectory using cancellous screws. Pullout strength tended to be higher when cortical screws were used in both CBT and the traditional trajectory, although the difference was not significant. Toggle testing showed no significant differences among the 4 groups. CONCLUSIONS The specific unconventional trajectory seemed to have a major impact on the increased strength obtained with CBT.

Acceleration of callus formation during fracture healing using basic fibroblast growth factor-kidney disease domain-collagen-binding domain fusion protein combined with allogenic demineralized bone powder

BackgroundTo repair fractures with large bone defects or gaps, demineralized allogenic bone matrix (DBM) is often applied to the fracture site. However, studies have shown that the use of DBM alone has limited efficacy for repairing fractures. In the present study, we developed an allogenic demineralized bone powder (DBP) with basic fibroblast-derived growth factor containing a polycystic kidney disease (PKD) domain and collagen-binding domain (CBD) from Clostridium histolyticum collagenase (ColH) and investigated the stimulatory effects of bFGF-PKD-CBD combined with allogenic DBP on bone growth in a mouse femur fracture model.MethodsDBP mixed with either phosphate-buffered saline (PBS) (DBP/PBS), 0.58 nmol basic fibroblast growth factor (bFGF) (0.58 nmol DBP/bFGF), 0.058 nmol bFGF-PKD-CBD (0.058 nmol DBP/bFGF-PKD-CBD), or 0.58 nmol bFGF-PKD-CBD (0.58 nmol DBP/bFGF-PKD-CBD) was grafted into fracture sites.ResultsbFGF-PKD-CBD/DBP composite accelerates callus formation in a bone fracture model in mice and clearly showed that the composite also increases bone mineral density at fracture sites compared to bFGF/DBP. In addition, bFGF-PKD-CBD/DBP increased callus volume and bone mineral content to similar levels in fractures treated with a tenfold higher amount of bFGF at 4 weeks.ConclusionsOur results suggest that bFGF-PKD-CBD/DBP may be useful for promoting fracture healing in the clinical setting.

Acceleration of bone union after structural bone grafts with a collagen-binding basic fibroblast growth factor anchored-collagen sheet for critical-size bone defects

Bone allografts are commonly used for the repair of critical-size bone defects. However, the loss of cellular activity in processed grafts markedly reduces their healing potential compared with autografts. To overcome this obstacle, we developed a healing system for critical-size bone defects that consists of overlaying an implanted bone graft with a collagen sheet (CS) loaded with basic fibroblast growth factor (bFGF) fused to the collagen-binding domain derived from a Clostridium histolyticum collagenase (CB-bFGF). In a murine femoral defect model, defect sites treated with CS/CB-bFGF had a significantly larger callus volume than those treated with CS/native bFGF. In addition, treatment with CS/CB-bFGF resulted in the rapid formation of a hard callus bridge and a larger total callus volume at the host-graft junction than treatment with CS/bFGF. Our results suggest that the combined use of CS and CB-bFGF helps accelerate the union of allogenic bone grafts.

Acceleration of bone formation during fracture healing by poly(pro-hyp-gly)10 and basic fibroblast growth factor containing polycystic kidney disease and collagen-binding domains from Clostridium histolyticum collagenase.

Growth factor delivered in combination with animal-derived collagen materials has been used to accelerate bone fracture healing in human patients. However, the introduction of bovine proteins into humans carries the risk of zoonotic and immunologic complications. Here, we developed a collagen-like polypeptide-based bone formation system consisting of poly(Pro-Hyp-Gly)10 , which mimics the triple helical conformation of collagen, and basic fibroblast growth factor (bFGF) fused to the polycystic kidney disease (PKD) domain and collagen-binding domain (CBD) of Clostridium histolyticum collagenase. Circular dichroism spectral analysis showed that when pepsin-soluble bovine type I collagen was treated at 50°C, a positive signal corresponding to the collagen triple helix at 220 nm was not detected. In contrast, poly(Pro-Hyp-Gly)10 retained the 220-nm positive peak, even when treated at 80°C. The combination of the collagen binding-bFGF fusion protein (bFGF-PKD-CBD) with poly(Pro-Hyp-Gly)10 induced greater bone formation compared to bFGF alone in mice bone fracture models. Taken together, these properties suggest that the bFGF-PKD-CBD/poly(Pro-Hyp-Gly)10 composite is a promising material for bone repair in the clinical setting.

Complications Associated With Spine Surgery in Patients Aged 80 Years or Older: Japan Association of Spine Surgeons with Ambition (JASA) Multicenter Study:

Study Design: Retrospective study of registry data. Objectives: Aging of society and recent advances in surgical techniques and general anesthesia have increased the demand for spinal surgery in elderly patients. Many complications have been described in elderly patients, but a multicenter study of perioperative complications in spinal surgery in patients aged 80 years or older has not been reported. Therefore, the goal of the study was to analyze complications associated with spine surgery in patients aged 80 years or older with cervical, thoracic, or lumbar lesions. Methods: A multicenter study was performed in patients aged 80 years or older who underwent 262 spinal surgeries at 35 facilities. The frequency and severity of complications were examined for perioperative complications, including intraoperative and postoperative complications, and for major postoperative complications that were potentially life threatening, required reoperation in the perioperative period, or left a permanent injury. Results: Perioperative complications occurred in 75 of the 262 surgeries (29%) and 33 were major complications (13%). In multivariate logistic regression, age over 85 years (hazard ratio [HR] = 1.007, P = 0.025) and estimated blood loss ≥500 g (HR = 3.076, P = .004) were significantly associated with perioperative complications, and an operative time ≥180 min (HR = 2.78, P = .007) was significantly associated with major complications. Conclusions: Elderly patients aged 80 years or older with comorbidities are at higher risk for complications. Increased surgical invasion, and particularly a long operative time, can cause serious complications that may be life threatening. Therefore, careful decisions are required with regard to the surgical indication and procedure in elderly patients.

Can the caudal extent of fusion in the surgical treatment of scoliosis in Duchenne muscular dystrophy be stopped at lumbar 5

Instrumentation and fusion to the sacrum/pelvis has been a mainstay in the surgical treatment of scoliosis in Duchenne muscular dystrophy (DMD) and is recommended to correct pelvic obliquity. The caudal extent of instrumentation and fusion in the surgical treatment of scoliosis in DMD has remained a matter of considerable debate, and there have been few studies on the use of segmental pedicle screw instrumentation for this pathology. From 2004 to 2007, a total of 28 patients with DMD underwent segmental pedicle screw instrumentation and fusion only to L5. Assessment was performed clinically and with radiologic measurements. All patients had a curve with the apex at L2 or higher preoperatively. Preoperative coronal curve averaged 74°, with a postoperative mean of 14°, and 17° at the last follow-up. The pelvic obliquity improved from 17° preoperatively to 6° postoperatively, and 6° at the last follow-up. Good sagittal plane alignment was recreated after surgery and maintained long term. In 23 patients with a preoperative L5 tilt of less than 15°, the pelvic obliquity was effectively corrected to less than 10° and maintained by adequately addressing spinal deformity, while five patients with a preoperative L5 tilt of more than 15° had a postoperative pelvic obliquity of more than 15°. Segmental pedicle screw instrumentation and fusion to L5 was effective and safe in patients with DMD scoliosis with a minimal L5 tilt (<15°) and a curve with the apex at L2 or higher, both initially and long term, obviating the need for fixation to the sacrum/pelvis. Segmental pedicle screw instrumentation and fusion to L5 was safe and effective in patients with DMD scoliosis with stable L5/S1 articulation as evidenced by a minimal L5 tilt of less than 15°, even though pelvic obliquity was significant. There was no major complication. With rigid segmental pedicle screw instrumentation, the caudal extent of fusion in the treatment of DMD scoliosis should be determined by the degree of L5 tilt. This method in appropriate patients can be a viable alternative to instrumentation and fusion to the sacrum/pelvis in the surgical treatment of DMD scoliosis.