Use of demineralized bone matrix in spinal fusion

Spinal fusion remains the gold-standard treatment for several pathological spine conditions. Although, autologous Iliac Crest Bone Grafting is considered the gold-standard graft choice to promote spinal fusion; however, it is associated with significant donor site morbidity and a limited graft quantity. Therefore, several bone graft alternatives have been developed, to augment arthrodesis. The purpose of this review is to present the results of clinical studies concerning the use of demineralized bone matrix (DBM), alone or as a composite graft, in the spinal fusion. A critical review of the English-language literature was conducted on Pubmed, using key word “demineralized bone matrix”, “DBM”, “spinal fusion”, and “scoliosis”. Results had been restricted to clinical studies. The majority of clinical trials demonstrate satisfactory fusion rates when DBM is employed as a graft extender or a graft enhancer. Limited number of prospective randomized controlled trials (4 studies), have been performed comparing DBM to autologous iliac crest bone graft in spine fusion. The majority of the clinical trials demonstrate comparable efficacy of DBM when it used as a graft extender in combination with autograft, but there is no clinical evidence to support its use as a standalone graft material. Additionally, high level of evidence studies are required, in order to optimize and clarify the indications of its use and the appropriate patient population that will benefit from DBM in spine arthrodesis.     

介绍一种应用于椎间融合植骨的简易方法

正2012年3月至今,我们在临床中不断探索尝试,将1 ml无菌注射器经过适当修剪,作为椎间植骨工具,可以将植骨颗粒准确高效地推送入椎间植骨位置,报道如下。1材料与方法在无菌手术器械台上,取5~6个1ml无菌注射器,用手术刀将无菌注射器针筒于0~0.1 ml刻度处切开一小斜面,针筒头端成一椭圆形开口(见图1);     

A poly(propylene glycol-co-fumaric acid) based bone graft extender for lumbar spinal fusion: in vivo assessment in a rabbit model

Study design: An animal model of posterolateral intertransverse process lumbar spinal fusion compared fusion rates amongst autologous bone (group 1), a porous, bioabsorbable, scaffold based on the biopolymer, poly(propylene glycol-co-fumaric acid) (PPF) (group 2), and a combination of autograft and the bioabsorbable scaffold (group 3). Objectives: To evaluate the feasibility of augmenting spinal fusion with an osteoconductive and bioabsorbable scaffold as an alternative or as an adjunct, i.e., an extender, to autograft. Summary of background data: There is little preclinical data on applications of bioabsorable bone graft extenders in spinal fusion. Methods: New Zealand White rabbits underwent single-level lumbar posterolateral intertransverse process fusion. Animals were treated with one of three materials: autologous bone (group 1), a bioabsorable material based on PPF (group 2), and the PPF biopolymer scaffold with autologous bone graft (group 3). Animals were evaluated at 6 weeks, and fusion was evaluated by manual palpation, and radiographic, histologic, and histomorphometric analyses. Results: Radiographic and manual palpation showed evidence of fusion in all three groups. Histomorphometric measurement of bone ingrowth showed the highest quantity of new bone in group 3 (91%), followed by group 1 (72%) and group 2 (53%). Conclusions: Results of this study suggested that osteoconductive bioabsorbable scaffolds prepared from PPF might be used as an autograft extender when applied as an adjunct to spinal fusion.     

颈前路钩椎关节减压和改良植骨术(附61例报告)

目的评估钩椎关节减压改良植骨术在颈椎手术中的应用价值,探讨其手术适应证。方法回顾性分析61例接受颈前路钩椎关节减压改良植骨术治疗的颈椎病,利用NDI和VAS评分评价疗效,X线片及CT检查评估融合情况。结果所有患者平均随访16.5个月(12~21个月),术后症状均得到改善,术后3、6个月NDI及VAS评分均显著改善(P<0.001)。术后18个月58例(95.1%)融合。结论钩椎关节减压改良植骨术治疗颈椎病可以提高融合率,避免常规术式中出现的供骨区并发症问题。该术式尤其适用于伴有神经根管狭窄的神经根型颈椎病或者混合型颈椎病。     

Fusion mass bone quality after uninstrumented spinal fusion in older patients

Older people are at increased risk of non-union after spinal fusion, but little is known about the factors determining the quality of the fusion mass in this patient group. The aim of this study was to investigate fusion mass bone quality after uninstrumented spinal fusion and to evaluate if it could be improved by additional direct current (DC) electrical stimulation. A multicenter RCT compared 40 and 100 μA DC stimulation with a control group of uninstrumented posterolateral fusion in patients older than 60 years. This report comprised 80 patients who underwent DEXA scanning at the 1 year follow-up. The study population consisted of 29 men with a mean age of 72 years (range 62–85) and 51 women with a mean age of 72 years (range 61–84). All patients underwent DEXA scanning of their fusion mass. Fusion rate was assessed at the 2 year follow-up using thin slice CT scanning. DC electrical stimulation did not improve fusion mass bone quality. Smokers had lower fusion mass BMD (0.447 g/cm²) compared to non-smokers (0.517 g/cm²) (P = 0.086). Women had lower fusion mass BMD (0.460 g/cm²) compared to men (0.552 g/cm²) (P = 0.057). Using linear regression, fusion mass bone quality, measured as BMD, was significantly influenced by gender, age of the patient, bone density of the remaining part of the lumbar spine, amount of bone graft applied and smoking. Fusion rates in this cohort was 34% in the control group and 33 and 43% in the 40 and 100 μA groups, respectively (not significant). Patients classified as fused after 2 years had significant higher fusion mass BMD at 1 year (0.592 vs. 0.466 g/cm², P = 0.0001). Fusion mass bone quality in older patients depends on several factors. Special attention should be given to women with manifest or borderline osteoporosis. Furthermore, bone graft materials with inductive potential might be considered for this patient population.     

Free vascularized bone graft in spinal surgery: indications and outcome in eight cases

In selected spinal deformities the use of a vascularized graft to establish fusion may be considered: compared to a non-vascularized graft it has superior mechanical properties, resulting in greater graft strength and stiffness, and greater effectiveness in facilitating union. Eight patients with a progressive spinal deformity (four cases) and malignancy (four cases) were treated with resection and/or correction and stabilization. To facilitate (multi)level fusion vascularized fibular grafts were used in two cervical and two thoracolumbar deformities. Fibular (two cases) or iliac grafts (two cases) were used in four cases of spinal reconstruction after vertebrectomy for malignancy. In all patients complete incorporation of the graft was obtained within 5 weeks to 8 months postoperatively. Complications occurred in three cases: one patient had a transient laryngeal edema and laryngeal nerve palsy. Another patient had a non-fatal deep vein thrombosis with pulmonary embolisms, successfully treated with anticoagulants. A third patient developed a lung infection and subsequently a deep infection around the dorsal instrumentation; after hardware removal the infection was controlled. At the latest follow-up (mean 30 months, range 24– 48 months) six out of eight patients are alive. One patient died 2.5 years after the intervention due to widespread metastases, while another patient died in the postoperative period due to unknown reasons. Vascularized bone graft in spinal surgery facilitates primary mechanical stability and rapid fusion, and it has higher resistance to infection. The variety of applications of a vascularized graft may extend the range of indications for the use of grafts in spinal surgery. Received: 14 October 1998 Revised: 13 February 1999 Accepted: 9 March 1999     

后路病灶清除植骨融合内固定手术治疗跳跃性脊柱结核的疗效分析

【摘要】 目的：总结跳跃性脊柱结核的临床特点,探讨一期后路病灶清除植骨融合内固定手术治疗跳跃性脊柱结核的疗效。方法：回顾性分析2016年7月~2022年5月我院手术治疗的31例跳跃性脊柱结核患者的临床资料,其中患者男18例,女13例,年龄49.5±27.5岁。其中2处病灶24例,3处病灶7例。对每例患者明确责任椎,确定手术病灶、融合节段、内固定方式,以制定个体化手术方案,随访29.7±14.7个月（15～85个月）。记录患者手术时间、术中出血量,并记录术中及术后并发症情况;术前和术后1个月、3个月、1年及末次随访的红细胞沉降（ESR）和C-反应蛋白（CRP）;术前及术后1周、1个月、3个月、1年及末次随访的疼痛视觉模拟评分（VAS）;术前及术后1周、末次随访时病灶后凸Cobb角;记录术前及末次随访时美国脊髓损伤协会（ASIA）分级;末次随访时采用Bridwell骨愈合标准分级以评估术后结核活动性、症状改善、畸形矫正及骨愈合。结果：31例患者中20例（65.4%）只有1处病灶出现临床症状,23例（74.2%）以疼痛为主诉入院,15例（48.4%）在病程中只有疼痛症状,而11例（35.5%）只有1处病灶出现疼痛症状,18例（58.1%）患者初诊时至少有1处病灶漏诊。所有患者手术顺利,手术时间280.0±52.2min（165～330min）,失血量567.7±332.0mL（150～1000mL）。术后出现脑脊液漏4例,切口感染3例,经对症处理后痊愈;所有结核病灶均治愈,未出现复发。术前及术后1个月、3个月、1年、末次随访时ESR为41.5±26.3mm/h、16.3±13.4mm/h、12.5±6.3mm/h、11.4±5.2mm/h、9.2±3.1mm/h;CRP为32.8±23.2mg/L、7.3±5.6mg/L、6.2±4.1mg/L、5.1±3.7mg/L、2.8±2.3mg/L;术前及术后1周、1个月、3个月、1年、末次随访时VAS评分为6.4±2.4分、2.4±1.7分、2.3±1.3分、1.6±0.9分、0.9±0.7分、0.4±0.3分。术后各个时间点CRP、ESR、VAS评分较术前均有显著改善（P＜0.05）。术前Cobb角25.7°±4.9°,术后1周15.4°±2.1°,末次随访时17.1°±2.3°,术后均较术前有统计学差异（P＜0.05）;10例存在术前神经功能损伤患者,末次随访时1例术前A级患者恢复至C级;4例术前B级患者1例恢复至C级,3例恢复至D级;5例术前C级患者2例恢复至D级,3例恢复至E级;术后6～12个月42处植骨病灶均获得骨融合,末次随访时34处病灶Bridwell Ⅰ级愈合,8处病灶Bridwell Ⅱ级融合。结论：对跳跃性脊柱结核患者,明确责任椎及各处病灶病变特点,一期后路病灶清除植骨融合内固定手术治疗安全且高效,能得到满意的疗效。     

Thoracolumbar spinal fractures: radiological results of transpedicular fixation combined with transpedicular cancellous bone graft and posterior fusion in 183 patients

In internal posterior fixation of thoracolumbar fractures combined with transpedicular cancellous bone graft and posterior fusion of the intervertebral facet joints at the level of the destroyed end plate it is still uncertain as to whether significant vertebral body collapse and loss of correction of the regional angle (RA) and the intervertebral angle (IVA) occur (after removal of the implants). These questions were investigated in a retrospective study of 183 consecutive patients, 18-65 years old, with a spinal fracture between the 9th thoracic and the 5th lumbar vertebral body (inclusive), treated operatively between 1988 and 1996 (27% had objective neurological deficit, 37% had multiple injuries). According to the Comprehensive Classification, 128 type A, 32 type B and 21 type C fractures were identified preoperatively. Changes in the anterior wedge angle (AWA), the IVA and the RA were measured preoperatively, and within 1 month, 9 months and 24 months postoperatively. The effect of implant failure was also evaluated. The normality of the distribution was tested using the Kolmogorov-Smirnov (K-S) test. The one-sample runs test and the t-test were used to evaluate angle changes. Angles in patients with and without implant failure were compared using the unpaired t-test. Almost complete restoration of the AWA could be achieved during operation. Postoperative changes in AWA were either very small or not significant. The reduced vertebral body did not collapse after 9 months, when most of the patients (170) underwent removal of the implants, but significant changes in IVA were found after implant removal. Correction of the RA was statistically significant before implant removal, but the RA 2 years after surgery had become almost the same as the preoperative values. Changes at the level of the intervertebral space, occurring after implant removal, contributed to the loss in the RA. Broken pedicle screws (10.9% of the patients) resulted in significant changes in the AWA and RA before implant removal, but did not influence the IVA.     

Simultaneous progression patterns of scoliosis,pelvic obliquity,and hip subluxation/dislocation in non-ambulatory neuromuscular patients: an approach to deformity documentation

Background

A triad of deformities—thoracolumbar scoliosis, pelvic obliquity, and femoral head (hip) subluxation/dislocation—occurs frequently in non-ambulatory neuromuscular patients, but their close inter-relationship is infrequently appreciated or quantified. We propose a deformity documentation approach to assess each component simultaneously.

Methods

The documentation assesses each component for maximal functional level, deformity, and flexibility/rigidity: deformity from antero-posterior radiographs (scoliosis—maximal functional position, pelvic obliquity—sitting, hip position—supine) and flexibility/rigidity from extent of repositioning on supine (spine, pelvis) and frog lateral (hip) radiographs. The approach was applied in 211 patients: Duchenne muscular dystrophy (110), spinal muscular atrophy (49), cerebral palsy (26), and other neuromuscular disorders (26).

Results

Measurement of 2124 radiological data points allowed for deformity (mild to moderate to severe) and flexibility/rigidity (fully reducible to partially to non-reducible) gradations for scoliosis, pelvic obliquity, and hip subluxation/dislocation. The charting documented: (1) numerical deformity and flexibility/rigidity changes [x-axis: age; y-axis: angulation (scoliosis and pelvic obliquity) and percent coverage (hip subluxation or dislocation) from 0–120]; and (2) grade deformity and flexibility/rigidity changes [x-axis: age; y-axis: deformity and flexibility/rigidity, following conversion of numerical measurements to a 1–5 grade scale]. In subgroups with the most extensive documentation, thoracolumbar and lumbar scoliosis extended into the sacrum with 98 % (114/116) accompanied by pelvic obliquity; and scoliosis developed more rapidly than hip deformity in 44 % (28/63), scoliosis and hip deformity developed at the same time in 40 % (25/63), and hip deformity developed more rapidly than scoliosis in 16 % (10/63) (Pearson’s chi-squared test p = 0.0501, almost significant).

Conclusion and significance

Documentation of the triad of neuromuscular deformities is applicable to all diagnoses; it outlines maximal functional level, deformity, and flexibility/rigidity at each site; and it shows the relationship between spine, pelvic, and hip deformation. Prospective charting will enhance both clinical management and clinical research into neuromuscular deformity.     

Autologous versus allogenic bone grafts in instrumented anterior cervical discectomy and fusion: a prospective study with respect to bone union pattern

Background The purpose of this prospective semi-randomised comparative study was to compare fusion rates, course of fusion, and occurrence of collapse and subsidence of autologous and allogenic bone grafts in instrumented anterior cervical fusion. The number of fused levels and the smoking status were investigated as potential factors influencing the bone-healing process. No similar prospective study on instrumented anterior cervical discectomy and fusion was found in the literature.Methods Seventy-nine consecutive patients were operated on using the Smith–Robinson technique with a single instrumentation system at one or two levels. Seventy-six cadaverous fibular bone grafts and 37 autologous iliac-crest bone grafts were inserted. All patients were followed up for at least 2 years.Results The radiographs obtained during the follow-up were analysed, and showed no statistical difference in fusion and collapse rate between autografts and allografts. Allografts showed significantly longer time to union. No case of graft migration was observed. No difference was found between fusion and collapse rate with respect to the number of fused levels in general, but greater time to union was seen in two-level fusions. When one- and two-level subgroups were compared, there was no evidence of any significant difference in fusion or collapse rates between autografts and allografts, and the healing process took longer in allogenic grafts. Smoking status did not alter any of the fusion or collapse rates, or the course of bone fusion.Conclusions This study demonstrates that allografts are suitable substitutes for autografts in instrumented ACDF. Prolonged time to union observed in allogenic bone grafts does not seem to be an important factor in instrumented procedures. Two-level grafting does not imply a significantly lower fusion rate, but longer time to union can be expected than with single-level instrumented procedures in both allograft and autograft subgroups. Our relatively small number of patients may not have been sufficient to decipher significant differences between smokers and non-smokers in the rate or course of fusion as previously reported.     

Septic hematogenous lumbar spondylodiscitis in elderly patients with multiple risk factors: efficacy of posterior stabilization and interbody fusion with iliac crest bone graft

The conservative and operative treatment strategies of hematogenous spondylodiscitis in septic patients with multiple risk factors are controversial. The present series demonstrates the outcome of 18 elderly patients (median age, 72 years) with septic hematogenous spondylodiscitis and intraspinal abscess treated with microsurgical decompression and debridement of the infective tissue, followed by posterior stabilization and interbody fusion with iliac crest bone graft in one or two lumbar segments. The majority of the patients were unsuccessfully treated with intravenous antibiotics prior to the operation. Antibiotic therapy was continued for more than 6 weeks postoperatively. Morbidity and early mortality amounted to 50 and 17%, respectively. Three patients died in the hospital from internal complications after an initial postoperative improvement of the inflammatory clinical signs and laboratory parameters. Fifteen patients recovered from the spinal infection. Three of them died several months after discharge (cerebral hemorrhage, malignancy and unknown cause). Twelve patients had excellent or good outcomes during the follow-up period of at least 1 year. The series shows that operative decompression and eradication of the intraspinal and intervertebral infective tissue with fusion and stabilization via a posterior approach is possible in septic patients with multiple risk factors and leads to good results in those patients, who survive the initial severe stage of the septic disease. However, the morbidity and mortality suggest that this surgical treatment is not the therapy of first choice in high-risk septic patients, but may be considered in patients when conservative management has failed.     

Added value of SPECT/CT in patients suspected of having bone infection: preliminary results

AIM: We evaluated the contribution of SPECT/CT as an adjunct to combined three-phase bone scintigraphy (planar and SPECT) for diagnosing and localizing bone infection. Subsequently, the diagnostic performance of SPECT/CT was compared to visual fusion of SPECT with data of additional CT, X-ray, or MRI studies (SPECT + CT/X-ray/MRI). MATERIALS AND METHODS: Thirty-one patients suspected of bone infection, presenting pathological findings on triple-phase bone scintigraphy, underwent additional SPECT/CT. The SPECT/CT-technology combines the acquisition of SPECT and CT data with the same imaging device enabling perfect overlay of anatomical and functional images. (99m)Tc-DPD was used as radiopharmaceutical in all patients. For data analysis findings of bone scintigraphy (planar scans as well as SPECT) were categorized as positive, negative, or equivocal for the presence of osteomyelitis. In a second step, they were compared with SPECT/CT and SPECT + CT/X-ray/MRI with respect to localization and classification of lesions. Validation was achieved by surgery, biopsy, or by clinical follow up over at least 9 months including microbiological and radiological findings. RESULTS: Three-phase bone scan (incl. SPECT) correctly classified 7 lesions as positive and 11 lesions as negative for osteomyelitis. Six scans were interpreted false positive, two false negative, and five as equivocal. Rating the latter as positive for osteomyelitis, sensitivity of bone scan was (78%), specificity (50%). SPECT/CT was true positive in 7 patients, and true negative in 19. There were two false positive and two false negative findings, one scan was equivocal (sensitivity 78%, specificity 86%). Definition of anatomical localization of inflammatory foci was much easier by SPECT/CT due to better depiction of underlying anatomical details. SPECT + CT/X-ray/MRI yielded the highest sensitivity (100% compared to 78% of SPECT/CT), if equivocal findings (5/31 compared to 1/31 for SPECT/CT) are rated as true positive for osteomyelitis. Among radiological techniques, MRI (2 x FP) and CT (2 x FN) proved equal and expectedly superior to X-ray in delivering the correct diagnosis. CONCLUSION: SPECT/CT improves the diagnostic performance of three-phase bone scan for osteomyelitis by avoiding false positive or equivocal results. An additional benefit over visual fusion of SPECT with X-ray, CT, or MRI studies could not be confirmed in our study.