Osteotomies through a fusion mass in the lumbar spine

Introduction

Flat-back syndrome is one of the main causes of surgical failure after lumbar fusion and can lead to a revision surgery to correct it. Three-column pedicle subtraction osteotomy is an efficient technique to restore lumbar lordosis (LL) for fixed sagittal malalignment. The fusion mass stemming from the past surgeries makes the procedure demanding as most anatomical landmarks are missing.

Material and methods

This review article will focus on the correction of this lack of LL through the fusion mass. We will successively review the preoperative management, the surgical specificities, and various types of clinical cases that can be encountered in flat-back syndromes.

Conclusion

PSO in the fixed fusion mass is technically demanding. Preoperative CT-scan and preoperative navigation allow us to push the limits when anatomical landmarks disappear. Bleeding and neurologic are the two major complications feared by the surgeon. The best way to avoid these revision surgeries is to restore a proper lumbar lordosis at the time of initial surgery by considering lumbo-pelvic indexes.

     

Anterior interbody fusion of the lumbar spine

Anterior interbody fusion of the lumbar spine by the extraperitoneal technique was performed in 47 patients with incapacitating low-back pain due to spondylolisthesis (26 patients) or disc degeneration (21 patients). The mean age was 38.2 years. Forty-five patients were re-examined 2--6 years postoperatively. According to the patients' own evaluation at follow-up, 53 per cent were free or almost free of back pain, 29 per cent were improved, 11 per cent unchanged and 7 per cent felt that the condition had deteriorated. Non-union occurred in nine patients, but among these three were free of pain, four were better and two were worse than before operation. The results do not seem to be correlated with age, sex, duration of pain before operation, degree of slipping in spondylolisthesis or the length of time out of work before surgery. It is concluded that this method may be worth continuing, but the patients should be selected with care.     

Knodt rod fusion of the lumbar spine

Thirty-six patients were examined at least 2 years after they underwent Knodt rod distraction fusion of the lumbar spine. Thirty-two patients had a satisfactory clinical result and 23 patients had a solid bone fusion. Six patients had significant complications. It is concluded that Knodt rod distraction fusion is a useful salvage procedure after failed anterior spinal fusion and as a primary procedure in spondylolisthesis.     

Thoracic herniation after lumbar spine fusion

We report on a 65-year-old male patient with rapid onset of incomplete paraparesis, based on a massive thoracic herniation following adjacent instability of the thoracolumbar spine after lumbar fusions with transpedicular instrumentation.     

Indications for lumbar spine fusion in the adult.

More than 20,000 lumbar spine fusions are performed annually in the United States. Results of surgery unfortunately are inconsistent and may reflect unsatisfactory patient selection. Indications for lumbar arthrodesis may arise in degenerative disk disease, deformity, distal extension of previous arthrodesis, trauma, spondylolisthesis, and spinal stenosis (in association with diskectomy or decompression). There are several techniques in the assessment of potential candidates for low lumbar arthrodesis.     

Indications for lumbar fusion in degenerative spine disease

The incidence of lumbar fusion surgeries has risen exponentially over the last 2 decades. Although a very useful and necessary surgery for specific conditions, spinal fusions have undeservingly earned a negative reputation. With stringent patient selection, lumbar fusions are highly efficacious. This article is intended to inform the reader of the indications for lumbar spinal fusion and discuss conditions that potentiate successful outcomes.     

A biomechanical comparison of posterolateral fusion and posterior fusion in the lumbar spine

Late postoperative complications occurred after posterior fusion and posterolateral fusion as a result of biomechanical alterations. The stress change between the two fusion procedures has not been well reported. To differentiate the biomechanical alteration that occurs with posterior fusion and posterolateral fusion of the lumbar spine, the load sharing of the vertebrae, disc, facet joint, bone graft, and the range of motion were computed in a finite element model. Five finite element models, including the intact lumber spine, posterior fusion, posterior fusion with implant, posterolateral fusion, and posterolateral fusion with implant, were created for stress analysis. The finite element model estimated that the differences between these two fusion procedures were within 7% in stress of the adjacent disc, 3% in force of the facet joint above the fusion mass, and 5% in the range of motion. However, the stress of the pedicle in posterolateral fusion without an implant was at most two times greater than that in the intact lumbar spine under lateral bending. The stress of pars interarticularis in posterior fusion without an implant was also at most two times greater than that in the intact lumbar spine under lateral bending. After the implant was added, the discrepancy between the two fusion procedures decreased but still remained a relatively large difference. Therefore, the largest changes of posterior fusion and posterolateral fusion were in the pars interarticularis and pedicle, respectively.     

Sexual complications of anterior fusion of the lumbar spine

Recently, there is renewed interest in anterior fusion for spondylolisthesis and congenital and paralytic scoliosis with pelvic obliquity. Some of the candidates are prepubertal boys. Sterility after surgery in urogenitally normal prepubertal boys will not be determined until these patients mature. A worldwide survey of 20 surgeons with 15-20 years of experience (4,500 cases) reports the frequency of sterility (retrograde ejaculation) to be 19 cases (0.42%) and impotence 20 cases (0.44%). One-fourth of the retrograde ejaculation cases resolved and became normal. Impotence is non-organic. The complication of retrograde ejaculation does not appear to be related to approach, though it was related to technique. While the complications of sterility and impotence following anterior fusion have been over-exaggerated, caution and informed consent from adult males and parents of prepubertal male children is advisable.     

Transforaminal interbody fusion versus anterior-posterior interbody fusion of the lumbar spine: a financial analysis

Lumbar interbody fusion can be performed anteriorly or posteriorly. An anterior approach generally requires an access surgeon and often is combined with a posterior fusion. A traditional posterior interbody fusion can destabilize the spinal motion segment and requires neural retraction. A new surgical technique, a transforaminal lumbar interbody fusion (TLIF), was recently described. It requires minimal neural retraction, and the disk space is exposed posterolaterally with removal of only one facet joint. This study compares the cost of an anterior-posterior one-level lumbar fusion with the cost of the same procedure performed using the TLIF technique. Table 1 lists the specific demographics. A retrospective review of the hospital charges of 80 patients undergoing interbody lumbar stabilization was conducted. The two groups consisted of 40 patients with an anterior-posterior fusion and 40 patients who were fused circumferentially using the TLIF technique. A cost analysis with normalization of 1998 dollars between the two groups was performed. The TLIF group had an average operative time of 213 minutes, compared with 269 minutes for the anterior-posterior group. In addition, an average additional 38 minutes were required to turn the patient from the anterior or posterior position. The average blood loss for the anterior-posterior procedure was 969 mL, compared with 489 mL for the TLIF group. Twenty-three of the anterior-posterior patients received an average of 2.2 units of blood and six of the TLIF patients received an average of 1.3 units. Use of the surgical intensive care unit was much lower in the TLIF group (38 of 40 patients versus 2 of 40 patients). The average length of stay was 6.1 days for the anterior-posterior group compared with an average of 3.3 days for the TLIF group. The average cost of the anterior-posterior patients was $49,085, compared with $33,784 for the TLIF group. Cost analysis between the two groups show the TLIF patients had an average savings of approximately $15,000 per admission. This cost comparison was conducted only for the time of the operative procedure. No attempt was made to analyze rates of fusion between the two groups or ultimate clinic outcome. There were no major complications in either group, and no patient returned to surgery for a lumbar spinal problem at the authors' hospital within 1 year of the index procedure.     

Experiences with surgical fusion of the lumbar spine]

Authors report on the results of the operative fusion of the lumbar spine performed by them between 1 March 1987 through 31 December 1990. Based on the assessment of 243 cases they call attention to the importance of the correct indication and operative technique and of the close supervision. It is stated that the use of the internal fixation improves the results of the operative fusions.     

Biochemistry of fusion mass consolidation in the sheep spine

We report here the biochemistry of fusion mass consolidation in sheep spines during a 1-year period following autogenous cortical-cancellous bone grafting and stabilization with Harrington distraction rods. Biochemical analysis of vertebral fusion mass included determination of wet weight and dry weight and quantification of glycosaminoglycan, collagen, calcium, and phosphate following extraction with neutral EDTA and proteolytic hydrolysis with papain. Our results showed that at 1 week after surgery, the fusion mass consisted of original cortical and cancellous bone graft material. The cortical bone graft was partially resistant to EDTA-papain treatment, resulting in a residue containing hydroxyproline and mineral. At 12 weeks after surgery, the fusion mass had become a homogeneous material, which, like cancellous bone graft, was completely susceptible to treatment by EDTA-papain. Collagen content of consolidating fusion mass was highest at 16 weeks after surgery when normalized to dry weight; glycosaminoglycan content was highest within 6 weeks after surgery. Mineral content was lowest at the 6-week stage but by 12 weeks after surgery, it was comparable with original bone grafting material. At 24 and 52 weeks after surgery, fusion mass consolidation was characterized by an increase in the proportion of organic and mineral components resistant to EDTA-papain. The appearance of the EDTA-papain-resistant material in the fusion mass coincided with formation of lamellar bone and successful consolidation.     

Laparoscopic fusion of the lumbar spine: minimally invasive spine surgery. A prospective multicenter study evaluating open and laparoscopic lumbar fusion

STUDY DESIGN: Two hundred-forty consecutive patients underwent laparoscopic instrumented interbody fusion using custom-designed instrumentation and BAK (Sulzer Spine Tech, Minneapolis, MN) fusion cages. The surgeries were performed at eight spine centers during U.S. Food and Drug Administration investigational device evaluation clinical trials. This cohort was compared with 591 consecutive patients undergoing open anterior fusion with the same device. OBJECTIVES: To investigate the feasibility and safety of the laparoscopic approach compared with that of open procedures. SUMMARY OF BACKGROUND DATA: In other areas of medicine, advances in laparoscopic surgical procedures have resulted in reduced morbidity, expense, and pain when compared with results of the open counterpart. METHODS: The open anterior procedure was performed using a retroperitoneal approach. The laparoscopic procedure was performed transperitoneally with carbon dioxide insufflation to provide visualization using a 10-mm endoscope. Two hollow, titanium, threaded interbody implants packed with autologous bone were inserted into the diseased interspace. RESULTS: The laparoscopy group had a shorter hospital stay and reduced blood loss but had increased operative time. Operative time improved in the laparoscopy group as surgeons' experience increased. Operative complications were comparable in both groups, with an occurrence of 4.2% in the open approach and 4.9% in the laparoscopic approach. Overall, the device-related reoperation rate was higher in the laparoscopy group (4.7% vs. 2.3%), primarily as a result of intraoperative disc herniation. Conversion to open procedure in the laparoscopy group was 10%, with most cases predictable and preventable. CONCLUSIONS: The laparoscopic procedure is associated with a learning curve, but once mastered, it is effective and safe when compared with open techniques of fusion.     

改良TLIF治疗腰椎管狭窄症

[目的]探讨改良经椎间孔椎间盘切除椎体间融合术(mTLIF)治疗腰椎管狭窄症手术疗效。[方法]2015年12月～2017年1月,本科采用改良TLIF治疗老年退变性腰椎管狭窄症患者68例,其中,男41例,女27例,年龄65～81岁,平均(68.37±6.30)。采用VAS及ODI评价腰椎功能改善情况;应用SF-36量表对生活质量进行调查评估。拍摄腰椎正侧位X线片。[结果]本组患者手术顺利,平均手术时间(120.59±28.46) min、平均术中失血量(254.57±42.87) ml。其中,68例患者中64例(94.12%)获得12个月以上的随访。患者ODI评分由术前(55.32±8.29)分减少至末次随访时的(23.23±5.34)分,差异有统计意义(P0.05);VAS评分由术前(8.50±0.92)分减少至末次随访时的(1.93±0.75)分,差异有统计学意义(P0.05)。SF-36评分由术前(463.91±40.18)分增加至末次随访时的(783.11±37.93)分,差异有统计学意义(P0.05)。[结论]改良TLIF手术入路操作相对简单、有效,术中神经损伤的风险也较小,能彻底减压,同时能获得满意的稳定性和骨性融合。