Lumbar arthrodesis for the treatment of back pain

Management of recurrent unilateral lumbar disc herniation in a single level: unilateral versus bilateral pedicle screws fixation with interbody fusion

Background

Lumbar interbody fusion procedure is a recognized surgical technique in management of a variety of lumbar pathologies including recurrent lumbar disc prolapse. Interbody fusion augmented by pedicle screw fixation has been considered to improve fusion rates and clinical outcomes. Interbody fusion is commonly associated with better fusion potentials through applying the bone graft in the load bearing, vascular position of the anterior, and middle spinal columns. However, it still remains unknown whether interbody fusion with unilateral pedicle screw fixation (UPSF) is superior to that with bilateral pedicle screw fixation (BPSF).

Aim of the work

The aim of this study is to evaluate the efficacy and safety of unilateral versus bilateral pedicle screw fixation associated with interbody fusion for the management of single level unilateral recurrent lumbar disc prolapse as regard the clinical and biomechanical results, operation time, intraoperative blood loss, and postoperative stay.

Material and methods

This observational prospective comparative study of the two groups who were operated either unilateral (group A /15 patients) or bilateral (group B/15 patients) pedicle screw fixation with interbody fusion was done. Patients were followed up for 1, 6, ad 12 months.

Results

Significant improvement in functional outcome of the two groups was noted compared to preoperatively, except in early postoperative period where the back VAS and ODI in the unilateral group was better than bilateral group. However, on further follow up, no significant difference was noticed. There was no significant difference comparing fusion rate, complication rate, and duration of hospital stay between the two groups at postoperative follow-up. There was significantly less blood loss, and significantly shorter operation time in the unilateral PS fixation group as compared with the bilateral PS fixation group in our study.

Conclusion

Our study suggested that TLIF with unilateral PS fixation was as safe and effective as that with bilateral PS fixation for the management of recurrent single level lumbar disc prolapse; it showed better clinical outcome scores of ODI and back VAS, and a significant reduction of the intraoperative blood loss as well as the operation time, without significant differences considering fusion rate, complication rate, and duration of hospital stay between the two groups at postoperative follow-up. However, BPSF with TLIF likely causes more degeneration at the cranial adjacent segment compared with UPSF techniques. Nevertheless, the long-term follow up is required to demonstrate the impact of these findings.

Double-level isthmic spondylolisthesis treated with posterior lumbar interbody fusion with cage

Objective: Double-level isthmic spondylolisthesis in the lumbar spine is rare. The authors report on 21 cases of double-level isthmic spondylolisthesis treated by posterior lumbar interbody fusion (PLIF) with cage.Patients and methods: Between 2005 and 2015, twenty-one patients with double-level isthmic spondylolisthesis who underwent posterior lumbar interbody fusion (PLIF) with cage were reviewed retrospectively. The VAS (Visual Analogue Scale) and JOA (Japanese Orthopedic Association) score were used to evaluate preoperative and postoperative clinical outcomes.Results: The back pain and sciatica decreased from 6.53 and 4.24 points preoperatively to 1.80 and 1.18 points on the VAS at final follow-up, respectively. The average JOA score improved from 13.4 ± 3.2 preoperative to 25.4 ± 1.5 (range, 17-28) points postoperative. The average recovery rate was 76.9%. The good and excellent rate was 85.7% (18/21). The fusion rate was 95.2% (20/21). Changes in disc height, degree of listhesis, whole lumbar lordosis, and sacral inclination following surgery were also observed.Conclusions: Our results suggest that PLIF with cage appears to be an appropriate technique for the treatment of double-level isthmic spondylolisthesis.

Lumbar fusion surgery for degenerative conditions is associated with significant resource and narcotic use 2 years postoperatively in the commercially insured: a medical and pharmacy claims study

BACKGROUND

Chronic back pain is one of the costliest and most complex medical conditions to manage, involving physiological, psychological, mechanical, social, and environmental factors. An increasing trend of lumbar fusion (LF) surgery for chronic back pain continues despite conflicting evidence for pain relief or improved long-term outcomes. Our goal was to assess medical and pharmacy utilization (including continued use of pain medication) over a 2-year period among patients receiving LF to relieve back pain for degenerative conditions without instability.

METHODS

We conducted a 2-year longitudinal cohort study of 1,422 commercially insured patients who received LF from January through September 2009, and who had continuous benefit eligibility through 2011. We assessed resource use among patients with ICD-9-CM diagnostic codes consistent with a degenerative condition, identified from Cigna's national claim database (CPT codes 22612, 22630 and/or 22558). Patients with fracture, tumor, infection, spondylolisthesis, inflammatory arthritis, or deformity diagnostic codes were excluded.

RESULTS

Over the 2 years following LF, 992 patients (70%) incurred $9.0 million in additional medical claims payments which averaged $9,383 per patient. These payments included pain management interventions and long term therapy services in 30% of patients. A subset of 850 patients (60%) also had pharmacy benefits and 829 (97.5%) received multiple pain-related classes of medication over the same period. The majority of patients continued on chronic narcotic use (62.5%), and 95% of patients on narcotics preoperatively continued narcotic utilization at two years. This pharmacy benefit subset incurred an additional $2.2 million for pain-related medications at an average cost of $2,600 per patient. Total average payment for patients with combined medical and pharmacy benefits was $12,283.

CONCLUSIONS

LF for patients with a degenerative lumbar diagnosis incurred significant resources postoperatively, and was followed by long-term pain and psychotropic medication utilization.

Allogeneic mesenchymal precursor cells (MPCs) combined with an osteoconductive scaffold to promote lumbar interbody spine fusion in an ovine model

BACKGROUND

Advances in immunomagnetic cell sorting have enabled isolation and purification of pleuripotent stem cells from marrow aspirates and have expanded stem cell therapies to include allogeneic sources.

PURPOSE

This study aimed to determine the safety and efficacy of allogeneic mesenchymal precursor cells (MPCs) combined with an osteoconductive scaffold in lumbar interbody spinal fusion using an ovine model.

STUDY DESIGN

Thirty-two skeletally mature ewes underwent a single-level interbody fusion procedure using a Polyetheretherketone fusion cage supplemented with either iliac crest autograft (AG) or an osteconductive scaffold (Mastergraft Matrix, Medtronic, Memphis, TN, USA) with 2.5×10(6) MPCs, 6.25×10(6) MPCs, or 12.5×10(6) MPCs.

METHODS

Plain radiographs and computed tomography scans were scored for bridging bone at multiple points during healing and at necropsy. The biomechanical competency of fusion was scored by manual palpation and quantified using functional radiographs at necropsy. Postnecropsy histopathology and histomorphometric analysis assessed the local response to MPC treatment and quantified the volume and connectivity of newly formed bridging bone. Safety was assessed by serum biochemistry, hematology, and organ histopathology.

RESULTS

Mesenchymal precursor cell treatment caused no adverse systemic or local tissue responses. All analyses indicated MPCs combined with an osteoconductive scaffold achieved similar or better fusion success as AG treatment after 16 weeks, and increasing the MPC dose did not enhance fusion. Manual palpation of the fusion site indicated more than 75% of MPC-treated and 65% of AG-treated animals achieved rigid fusion, which was corroborated with functional radiography. Computed tomography fusion scores indicated all animals in the MPC- and AG-treatment groups were fused at 16 weeks, yet X-ray scores indicated only 67% of the AG-treated animals were fused. Histomorphometry analyses showed equivalent outcomes for fusion connectivity and bony fusion area for MPC- and AG-treated groups. Approximately 6% residual graft material remained in the MPC-treated fusion sites at 16 weeks.

CONCLUSIONS

Adult allogeneic MPCs delivered using an osteoconductive scaffold were both safe and efficacious in this ovine spine interbody fusion model. These results support the use ofallogeneic MPCs as an alternative to AG for lumbar interbody spinal fusion procedures.

Percutaneous injection of autologous bone marrow concentrate cells significantly reduces lumbar discogenic pain through 12 months

Degenerative disc disease (DDD) induces chronic back pain with limited nonsurgical options. In this open label pilot study, 26 patients (median age 40 years; range 18-61) received autologous bone marrow concentrate (BMC) disc injections (13 one level, 13 two levels). Pretreatment Oswestry disability index (ODI) and visual analog scale (VAS) were performed to establish baseline pain scores (average 56.5 and 79.3, respectively), while magnetic resonance imaging was independently scored according to the modified Pfirrmann scale. Approximately 1 ml of BMC was analyzed for total nucleated cell (TNC) content, colony-forming unit-fibroblast (CFU-F) frequency, differentiation potential, and phenotype characterization. The average ODI and VAS scores were reduced to 22.8 and 29.2 at 3 months, 24.4 and 26.3 at 6 months, and 25.0 and 33.2 at 12 months, respectively (p ≤ .0001). Eight of twenty patients improved by one modified Pfirrmann grade at 1 year. The average BMC contained 121 × 10(6) TNC/ml with 2,713 CFU-F/ml (synonymous with mesenchymal stem cells). Although all subjects presented a substantial reduction in pain, patients receiving greater than 2,000 CFU-F/ml experienced a significantly faster and greater reduction in ODI and VAS. Subjects older than 40 years who received fewer than 2,000 CFU-F/ml experienced an average pain reduction of 33.7% (ODI) and 29.1% (VAS) at 12 months, while all other patients' average reduction was 69.5% (ODI, p = .03) and 70.6% (VAS, p = .01). This study provides evidence of safety and feasibility in the nonsurgical treatment of DDD with autologous BMC and indicates an effect of mesenchymal cell concentration on discogenic pain reduction.

Perioperative and long-term clinical outcomes for bone morphogenetic protein versus iliac crest bone graft for lumbar fusion in degenerative disk disease: systematic review with meta-analysis

STUDY DESIGN

Systematic review with meta-analysis.

OBJECTIVES

To compare the perioperative and long-term postoperative effectiveness of bone morphogenetic protein (BMP) for lumbar arthrodesis in skeletally mature adults with degenerative disk disease (DDD) to that of the current golden standard treatment, iliac crest autologous bone graft (ICBG).

SUMMARY OF BACKGROUND DATA

The treatment efficacy of lumbar arthrodesis in DDD is a complex clinical and economic issue for patients and health care providers.

METHODS

Comprehensive electronic literature search was performed using following databases: Ovid MEDLINE; Embase; Cochrane Library; Central Register of Controlled Trials (CENTRAL); Database of Abstracts of Reviews of Effects; Methodology Register; Technology Assessment Database; and Economic Evaluation Database. The full year ranges of each database until May of 2012 were included.

RESULTS

Eight randomized controlled clinical trials of 383 citations were selected. The included studies involved 1138 participants. The pooled 2-year postoperative clinical outcomes were equivalent in BMP and ICBG groups, and exceeded minimum clinically important differences for Oswestry Disability Index, SF-36 (physical scale), and numeric rating scale (back pain). ICBG was associated with increased pain and complications at the donor site (P<0.01). The pooled average operative time was 21 minutes less in BMP versus ICBG (P<0.001). The pooled rate of additional surgical treatment was 2 times less in the BMP than in the ICBG groups (P=0.006). The pooled risk of nonunion at 24-month follow-up was 2 times less in the BMP than in the ICBG groups (P=0.037), however, this effect was likely biased.

CONCLUSIONS

BMP, in particular rhBMP-2, is a good alternative to autogenous bone graft, especially in cases when harvesting of autologous bone is contraindicated or undesirable, operation time is limited, and there are no contraindications for BMP use.However, the current study did not reveal evidence robust enough to develop strong medical recommendations concerning BMP use for lumbar arthrodesis in degenerative disk disease.

Efficacy and safety of pamidronate in Modic type 1 changes: study protocol for a prospective randomized controlled clinical trial

Background

Erosive degenerative disc disease, also known as Modic type 1 changes, is usually characterized by low back pain with an inflammatory pain pattern, as seen in spondyloarthropathies. Intravenous pamidronate has proven to be effective in patients with ankylosing spondylitis who are refractory to nonsteroidal antiinflammatory drugs, and in painful bone diseases in general, such as Paget’s disease, fibrous dysplasia or vertebral fractures. We therefore hypothesize that pamidronate would be effective in treating low back pain associated with Modic type 1 changes.

Methods/Design

This study, called PEPTIDE (short for the French title “Etude Prospective sur l’Efficacité et la tolérance du PamidronaTe dans les dIscopathies Degeneratives Erosives”), will be a double-blind, randomized, placebo-controlled, parallel group, phase two clinical trial. A total of 48 patients will be recruited. These patients will be randomly assigned to one of the two groups, with 24 patients in each group: one group will be given pamidronate and the other a placebo. Pamidronate will be administered at a dose of 90 mg per day for two days consecutively, and every patient, irrespective of treatment group, will be given paracetamol to maintain blinding by preventing drug-induced fever. The primary outcome measure is a between-group difference of 30 points on a 100 mm Visual Analogue Scale (VAS) at three months. Secondary outcome measures are improvement in functional status and the drug’s safety. Primary and secondary outcome measures will be assessed at each visit (inclusion, at six weeks, three months, and six months). If the primary goal is not attained, the patient will be offered a rigid or semi-rigid back brace, irrespective of the treatment group.

Discussion

To date, only local treatments, for example intradiscal corticosteroid therapy, lumbar arthrodesis or back braces have been studied in randomized, controlled trials, with controversial results. This trial is currently ongoing and, if conclusive, should provide physicians with an acceptable alternative to those treatments. The results should be publicly available in spring 2015.

Trial registration

ClinicalTrials.gov number, NCT01799616.

Effects of interspinous spacers on lumbar degenerative disease

The present study aimed to evaluate the early effects of interspinous spacers on lumbar degenerative disease. The clinical outcomes of 23 patients with lumbar degenerative disease, treated using interspinous spacer implantation alone or combined with posterior lumbar fusion, were retrospectively studied and assessed with a visual analogue scale (VAS) and the Oswestry Disability Index (ODI). Pre-operative and post-operative interspinous distance, disc space height, foraminal width and height and segmental lordosis were determined. The early effects and complications associated with the interspinous spacers were recorded. The surgical procedures performed with the in-space treatment were easy and minimally invasive. The VAS scores and ODI were improved post-operatively compared with pre-operatively. Significant changes in the interspinous distance, disc space height, foraminal width and height and segmental lordosis were noted. In-space treatment for degenerative lumbar disease is easy and safe, with good early effects. The in-space system provides an alternative treatment for lumbar degenerative disease.

Spinal fusion in the treatment of chronic low back pain: rationale for improvement

Results following fusion for chronic low back pain (CLBP) are unpredictable and generally not very satisfying. The major reason is the absence of a detailed description of the symptoms of patients with pain, if present, in a motion segment of the spine. Various radiological findings have been attributed to discogenic pain, but if these radiological signs were really true signs of such pain, fusion would have been very successful. If discogenic pain exists, it should be possible to select these patients from all others within the CLBP population. Even if this selection were 100% perfect, however, identification of the painful segment would remain, and at present there is no reliable test for doing so. Regardless of whether an anterior or posterior type of fusion is performed, or even if artificial discs are used, solving the puzzle of pain associated with the presumed segmental disorder must be the primary goal.

Regenerating nucleus pulposus of the intervertebral disc using biodegradable nanofibrous polymer scaffolds

Low back pain is a leading health problem in the United States, which is most often resulted from nucleus pulposus (NP) degeneration. To date, the replacement of degenerated NP relies entirely on mechanical devices. However, a biological NP replacement implant is more desirable. Here, we report the regeneration of NP tissue using a biodegradable nanofibrous (NF) scaffold. Rabbit NP cells were seeded on the NF scaffolds to regenerate NP-like tissue both in vitro and in a subcutaneous implantation model. The NP cells on the NF scaffolds proliferated faster than those on control solid-walled (SW) scaffolds in vitro. Significantly more extracellular matrix (ECM) production (glycosaminoglycan and type II collagen) was found on the NF scaffolds than on the control SW scaffolds. The constructs were then implanted in the caudal spine of athymic rats for up to 12 weeks. The tissue-engineered NP could survive, produce functional ECM, remain in place, and maintain the disc height, which is similar to the native NP tissue.

Spinal fusion-hardware construct: Basic concepts and imaging review

The interpretation of spinal images fixed with metallic hardware forms an increasing bulk of daily practice in a busy imaging department. Radiologists are required to be familiar with the instrumentation and operative options used in spinal fixation and fusion procedures, especially in his or her institute. This is critical in evaluating the position of implants and potential complications associated with the operative approaches and spinal fixation devices used. Thus, the radiologist can play an important role in patient care and outcome. This review outlines the advantages and disadvantages of commonly used imaging methods and reports on the best yield for each modality and how to overcome the problematic issues associated with the presence of metallic hardware during imaging. Baseline radiographs are essential as they are the baseline point for evaluation of future studies should patients develop symptoms suggesting possible complications. They may justify further imaging workup with computed tomography, magnetic resonance and/or nuclear medicine studies as the evaluation of a patient with a spinal implant involves a multi-modality approach. This review describes imaging features of potential complications associated with spinal fusion surgery as well as the instrumentation used. This basic knowledge aims to help radiologists approach everyday practice in clinical imaging.

Do facet screws provide the required stability in lumbar fixation? A biomechanical comparison of the Boucher technique and pedicular fixation in primary and circumferential fusions

BACKGROUND

Transfacet pedicle screws are scarcely used in primary posterior fixation, and have limited use unilaterally or with existing anterior instrumentation. Nevertheless, the incomplete literature suggests equivalent or better performance of ipsilateral, bilateral, facet screws compared to bilateral pedicle screws.

METHODS

Two groups of seven human cadaver spines (L3-S1) were tested under pure moments of 6 Nm. Each specimen was tested in a primary and circumferential fixation (Spacer, Spacer+Plate) environment. Both transfacet and bilateral pedicle screws were used as posterior fixation, in separate groups. Motion was obtained at L4-L5 for single-level constructs in flexion-extension, lateral bending and axial rotation modes.

FINDINGS

In primary fixation, both transfacet and bilateral pedicle screws reduced motion below intact levels. Statistically, the level of circumferential fixation (anterior, posterior, or both) proved to be more influential than the type of posterior fixation. Incorporating a spacer and plate with pedicle screws provided a greater relative gain in stability than with facet screws. The interpretation is explained through a model describing the location of fixation with respect to the center-of-rotation of the vertebral bodies. In lateral bending and axial rotation, bilateral pedicle screw constructs were stiffer than transfacet pedicle screw constructs as a trend.

INTERPRETATION

Transfacet pedicle screws provided similar fixation to bilateral pedicle screws in primary and circumferential fixations during flexion-extension. In the other modes, transfacet screw rigidity is, on average, less than bilateral pedicle screws when used alone, but with the addition of other anterior instrumentation the differences are minimized. Therefore, facet screws are warranted based on the surgical effect desired, and in the presence of additional anterior fixation.

THE HARTSHILL HORSESHOE: THE TREATMENT OF CHRONIC PAIN PATIENTS WITH DISCOGENIC PAIN IN THE ABSENCE OF NEURAL COMPRESSION A PROSPECTIVE 2½- TO 3-YEAR REVIEW

Interbody fusion is a well-recognized technique to achieve spinal fusion. The advantage of using tricortical blocks as opposed to the dowel technique is that intervertebral disc height can be restored. Both techniques can be performed either by the anterior or posterior approach.

The traditional tricortical block technique has advantages over using dowels as it is a more stable construct and can restore intervertebral disc height. However, autologous bone graft has an unpredictable behavior causing potential problems of disc space collapse, forward displacement of the graft and donor bone graft site morbidity.

The Hartshill horseshoe was developed to overcome these autograft problems. It is an implant that is placed within the periphery of the intervertebral disc space where the vertebral end plate is strongest to resist compression forces. It has holes that allow screw fixation of the implant to bone to provide immediate stability and a central area for bone graft where the vertebral body is most vascular to allow incorporation of such a graft.

Previous reports on the Hartshill horseshoe have used autograft (single tricortical graft). This prospective study reports the clinical and radiological results of 19 patients who underwent this procedure using xenograft 2½ to 3 years postoperative. The radiological results do not show any evidence of loosening of the screws or implant nor evidence of intervertebral disc space subsidence. It was not possible to assess the exact incidence of spinal fusion.

Annulus cells from more degenerated human discs show modified gene expression in 3D culture compared with expression in cells from healthier discs

BACKGROUND CONTEXT

Understanding gene expression patterns of disc cells in culture is important as we develop biologic therapies for disc degeneration. The objective of the present study was to determine if cells from more degenerated discs expressed different genes, or differed in their expression patterns, compared with patterns of cells from healthier discs.

PURPOSE

To determine if annulus cells from more degenerated discs expressed different gene expression patterns compared with patterns of cells from healthier discs using genome-wide analysis.

STUDY DESIGN

Cells from human annulus tissue were grown in three-dimensional (3D) culture and their gene expression patterns analyzed with Affymetrix microarray analysis. Gene expression patterns of cells from more degenerated discs (Thompson Grades IV and V) were compared with patterns from cells from healthier discs (Thompson Grades I, II, and III).

METHODS

After approval by our human subjects institutional review board, annulus cells were obtained from lumbar discs of seven subjects with Thompson Grades I, II, or III and from five subjects with discs of Thompson Grades IV and V. Cells were grown in 3D culture for 2 weeks; 3D cultures were used because this microenvironment more closely mimics the in vivo condition. mRNA was harvested, processed for Affymetrix genome-wide gene analysis, and data analyzed with p values adjusted so as to compensate for false discovery rates.

RESULTS

GeneSifter analyses showed that cells from more degenerated discs had 320 genes significantly upregulated, and 104 genes significantly downregulated compared with cells from healthier discs. Important genes included those related to: 1) the extracellular matrix (ECM) (keratin-associated protein 1-1, hyaluronan synthase 2, and nexin were upregulated; biglycan, collagen type VI alpha 2, thrombospondin 3, laminen alpha 1, fibronectin type III domain-containing protein 1, elastin microfibril interfacer 2, fibulin 2, and nidogen 1 and 2 were downregulated); 2) ECM proteolysis (ADAMTS6 was upregulated); 3) cell proliferation (never in mitosis gene 1-related kinase 3, cell division cycle 2-like 5 [cholinesterase-related cell division controller], RAB42 [member of RAS oncogene family], and cyclin-dependent kinase 6 were upregulated; RAS-like GTP-binding 1 was downregulated); 4) apoptosis (BCL2-like 11 and p53-inducible nuclear protein 1 were upregulated; caspase recruitment domain family, member 10, caspase-1 dominant-negative inhibitor pseudo-ICE, and caspase 9 and FADD-like apoptosis regulator were downregulated); and 5) growth factors, inflammatory mediators, and other genes (fibroblast growth factor 1, pregnancy-associated plasma protein-A, interleukin 1 alpha, and interleukin 7 were upregulated; TGF-beta-induced transcript 1, interleukin 26 and interleukin 1 receptor-like 1, tumor necrosis factor, alpha-induced protein 2, and chemokine (C-X3-C motif) ligand 1 were downregulated).

CONCLUSIONS

Data presented here show that annulus cells from more degenerated discs show modified gene expression in 3D culture. Important gene variations involved expression of interleukins, cytokines, ECM components, and apoptosis regulators. Results presented here have potential application in future cell-based biologic therapies for disc degeneration.

Debating the value of spine surgery

Lumbar arthrodesis is a commonly performed operative procedure for the treatment of low back pain. Recently, total disc arthroplasty has gained some acceptance among surgeons and patients. However, the indications for and results of back pain surgery remain controversial and confusing. Available information suggests that meaningful functional improvement from these procedures is debatable and that the cost of such elective operations is high. Currently, lumbar disc replacement has gained minimal support from governmental and private payers. Among those attending this symposium at the 2009 Annual Meeting of the AOA, the vast majority concurred that Medicare and private insurance should not necessarily pay for disc replacement surgery. Interestingly, among this skeptical group of orthopaedic surgeons, only 23% believed that degeneration of the intervertebral disc is the major cause of low back pain. When asked the hypothetical question, "If you experienced chronic low back pain with degenerative changes at one level, what course of treatment would you opt for?" 61% responded that they would choose nonoperative treatment and 38%, that they would choose no treatment. Of more than 100 respondents, only one responded that he or she would undergo fusion and one admitted a willingness to undergo disc replacement in this hypothetical scenario.

A randomized placebo-controlled trial of intradiscal methylene blue injection for the treatment of chronic discogenic low back pain

A preliminary report of clinical study revealed that chronic discogenic low back pain could be treated by intradiscal methylene blue (MB) injection. We investigated the effect of intradiscal MB injection for the treatment of chronic discogenic low back pain in a randomized placebo-controlled trial. We recruited 136 patients who were found potentially eligible after clinical examination and 72 became eligible after discography. All the patients had discogenic low back pain lasting longer than 6 months, with no comorbidity. Thirty-six were allocated to intradiscal MB injection and 36 to placebo treatment. The principal criteria to judge the effectiveness included alleviation of pain, assessed by a 101-point numerical rating scale (NRS-101), and improvement in disability, as assessed with the Oswestry Disability Index (ODI) for functional recovery. At the 24-month follow-up, both the groups differed substantially with respect to the primary outcomes. The patients in MB injection group showed a mean reduction in pain measured by NRS of 52.50, a mean reduction in Oswestry disability scores of 35.58, and satisfaction rates of 91.6%, compared with 0.70%, 1.68%, and 14.3%, respectively, in placebo treatment group (p<0.001, p<0.001, and p<0.001, respectively). No adverse effects or complications were found in the group of patients treated with intradiscal MB injection. The current clinical trial indicates that the injection of methylene blue into the painful disc is a safe, effective and minimally invasive method for the treatment of intractable and incapacitating discogenic low back pain.

Short segment coronal plane deformity after two-level lumbar total disc replacement

STUDY DESIGN

Case series of 2-level lumbar disc arthroplasties treated by the authors.

OBJECTIVE

Identify a potentially significant failure rate of 2-level disc arthroplasty due to coronal plane instability.

SUMMARY OF BACKGROUND DATA

Arthrodesis remains the standard for surgical treatment of degenerative disc disease, despite concerns about adjacent level degeneration and persistent postoperative pain in some patients. Total disc arthroplasty has been proposed as a way to reduce these problems. Intermediate follow-up of 1-level procedures demonstrates promising safety and improved pain scores. Some surgeons are expanding the surgical indications to more challenging settings, including multilevel disease.

METHODS

We report here our experience with 4 cases of failed 2-level disc arthroplasty.

RESULTS

We have seen 4 patients with failed 2-level lumbar arthroplasty, of those 2 performed in Germany and 2 performed in our state by 2 different experienced spine surgeons. The 2 local cases represent 29% (2/7) of all 2-level CHARITE arthroplasties performed within our state. All 4 patients presented within 11 to 13 months of implantation with increased back pain and radicular symptoms. The mechanism of failure was coronal instability due to small deviations of the prostheses from a midline position in all 4 cases.

CONCLUSION

Disc arthroplasty appears to be a safe and effective treatment for 1-level lumbar degenerative disc disease. Although promising biomechanical reports of 2-level models are emerging, we are concerned by the rate of failures of 2-level arthroplasty that we are seeing. It appears that the potential for coronal plane instability increases as the number of levels increases. Given the costs and risks associated with these procedures, we feel that this issue deserves the attention of the spine surgery community despite the limited numbers in this report.

Lumbar posterolateral fusion inhibits sensory nerve ingrowth into punctured lumbar intervertebral discs and upregulation of CGRP immunoreactive DRG neuron innervating punctured discs in rats

Degeneration of lumbar intervertebral discs is thought to be a cause of low back pain. Studies have found that a cause of discogenic low back pain is intervertebral disc inflammation and axonal growth of afferent fibers innervating the disc. Lumbar spine fusion for chronic discogenic low back pain is considered an effective procedure. However, no study has investigated the mechanism of pain relief. We did this by applying Fluoro-Gold (FG) to the ventral aspect of the L4-L5 intervertebral discs of 40 rats. We exposed the nucleus pulposus to the annulus fibrosus in a disc punctured model. Rats were divided into 4 groups. Group A: Punctured intervertebral disc with sham posterolateral fusion (PLF) (n = 10), Group B: Punctured intervertebral disc with PLF (n = 15), Group C: Normal intervertebral disc (no puncture) with PLF (n = 10), and Group D: Normal disc (no disc puncture) with sham PLF (n = 5). Four weeks after surgery, bilateral L1-L5 dorsal root ganglia (DRGs) were stained with growth-associated protein 43 (GAP43), a marker of axonal growth, and calcitonin gene-related peptide (CGRP), a neuropeptide marker of pain. Bone union was evaluated using X-ray imaging. Of the FG-labeled neurons, the proportions of GAP43- and CGRP-immunoreactive (IR) neurons in Group A were significantly higher than in Group D (P < 0.05). The proportions of GAP43- and CGRP-IR neurons in bone union rats in Group B were significantly lower than in nonunion rats in Group B and in the rats in Group A (P < 0.05). No significant differences in GAP43- and CGRP-IR neurons were observed between bone union and nonunion rats in Group C and the rats in Group D (P > 0.05). PLF is strongly related to the downregulation of GAP43 and CGRP expression. Therefore, PLF may suppress the increase of inflammatory neuropeptides and the process of axonal growth. Moreover, these results may explain, in part, the mechanism of pain relief following lumbar spinal fusion for chronic discogenic low back pain in humans.

Bone densitometry within titanium lumbar interbody fusion cages: a computed tomography feasibility study

STUDY DESIGN

The use of lumbar fusion cages to augment interbody arthrodesis has become popular. Previous studies have shown that titanium cages may obscure information within and around the cage, confounding assessments of fusion. Densitometry within cages, if possible, could be an important outcome variable for comparing different cage augmented fusion treatments.

OBJECTIVE

The purpose of this feasibility study was to (1) validate CT-based (computer tomography-based) density evaluations within titanium cages in a phantom model, and (2) demonstrate that intrametal cage lucencies can be produced by CT reconstruction artifacts and do not necessarily represent bone fragmentation or fibrous and cartilaginous tissue.

METHODS

An anthropomorphic lumbar spine phantom was used. Dual titanium cages were inserted into 6 anterior-middle column replicas, and the cages were filled with 10, 100, or 400 mg/cc hydoxyapatiite equivalent material. The column replicas were composed of either fibrous/cartilaginous tissue equivalent material or trabecular bone equivalent material. Column replicas were placed within the phantom and imaged with CT. Direct axial and reformatted sagittal and coronal images were evaluated for artifact. Region of interest analysis was performed for intracage density.

RESULTS

Intracage CT values calculated from axial, sagittal, and coronal images were directly related to the true CT values of the materials (r = 0.99, P < 0.0001). CT was used to distinguish between fibrous tissue and bone within cages. CT values within cages overestimated the intracage materials' true values (paired t test, P < 0.001). Intracage CT values were correctable and could be converted to bone mineral content. Intracage CT values were not affected by adjacent anterior-middle column material differences (fibrous/cartilaginous tissue vs. trabecular bone) (paired t test, P > 0.05). Lucent streaking within and adjacent to cages was similar to clinical images.

CONCLUSION

In this phantom-based study, densitometry was performed within titanium cages, even in the presence of CT artifact. These results support further pursuit of this potential assessment tool.

Unilateral transforaminal lumbar interbody fusion: a review of the technique, indications and graft materials

Transforaminal lumbar interbody fusion (TLIF) is an alternative interbody fusion procedure in which interbody space is accessed via a path that runs through the far lateral portion of the vertebral foramen. TLIF reduces the potential complications of other approaches, including the transabdominal approach or posterior lumbar interbody fusion (PLIF), but still achieves clinical outcomes and circumferential fusion results comparable with PLIF. Operative indications for TLIF are contested among many spine experts. The optimal indications for using this technique are spondylolisthesis, degenerative disc disease with a specific discogenic pain pattern, lumbar stenosis with instability and recurrent lumbar disc herniation with radiculopathy. Various instrumentation techniques and graft materials are available to use in TLIF, and each option has benefits and disadvantages. Further research is needed, however, TLIF with one cage and excised local bone and augmented with a bilateral pedicle screw seems to be an effective and affordable treatment.

Does Wallis implant reduce adjacent segment degeneration above lumbosacral instrumented fusion?

Delayed complications following lumbar spine fusion may occur amongst which is adjacent segment degeneration (ASD). Although interspinous implants have been successfully used in spinal stenosis to authors' knowledge such implants have not been previously used to reduce ASD in instrumented lumbar fusion. This prospective controlled study was designed to investigate if the implantation of an interspinous implant cephalad to short lumbar and lumbosacral instrumented fusion could eliminate the incidence of ASD and subsequently the related re-operation rate. Groups W and C enrolled initially each 25 consecutive selected patients. Group W included patients, who received the Wallis interspinous implant in the unfused vertebral segment cephalad to instrumentation and the group C selected age-, diagnosis-, level-, and instrumentation-matched to W group patients without interspinous implant (controls). The inclusion criterion for Wallis implantation was UCLA arthritic grade <II, while the exclusion criteria were previous lumbar surgery, severe osteoporosis or degeneration >UCLA grade II in the adjacent two segments cephalad to instrumentation. All patients suffered from symptomatic spinal stenosis and underwent decompression and 2-4 levels stabilization with rigid pedicle screw fixation and posterolateral fusion by a single surgeon. Lumbar lordosis, disc height (DH), segmental range of motion (ROM), and percent olisthesis in the adjacent two cephalad to instrumentation segments were measured preoperatively, and postoperatively until the final evaluation. VAS, SF-36, and Oswestry Disability Index (ODI) were used. One patient of group W developed pseudarthrosis: two patients of group C deep infection and one patient of group C ASD in the segment below instrumentation and were excluded from the final evaluation. Thus, 24 patients of group W and 21 in group C aged 65+ 13 and 64+ 11 years, respectively were included in the final analysis. The follow-up averaged 60 +/- 6 months. The instrumented levels averaged 2.5 + 1 vertebra for both groups. All 45 spines showed radiological fusion 8-12 months postoperatively. Lumbar lordosis did not change postoperatively. Postoperatively at the first cephalad adjacent segment: DH increased in the group W (P = 0.042); ROM significantly increased only in group C (ANOVA, P < 0.02); olisthesis decreased both in flexion (P = 0.0024) and extension (P = 0.012) in group W. The degeneration or deterioration of already existed ASD in the two cephalad segments was shown in 1 (4.1%) and 6 (28.6%) spines in W and C groups, respectively. Physical function (SF-36) and ODI improved postoperatively (P < 0.001), but in favour of the patients of group W (P < 0.05) at the final evaluation. Symptomatic ASD required surgical intervention was in 3 (14%) patients of group C and none in group W. ASD remains a significant problem and accounts for a big portion of revision surgery following instrumented lumbar fusion. In this series, the Wallis interspinous implant changed the natural history of ASD and saved the two cephalad adjacent unfused vertebra from fusion, while it lowered the radiographic ASD incidence until to 5 years postoperatively. Longer prospective randomized studies are necessary to prove the beneficial effect of the interspinous implant cephalad and caudal to instrumented fusion. We recommend Wallis device for UCLA degeneration I and II.

Diagnosis and surgical treatment of back pain originating from endplate

Twenty-one patients with back pain originating from the endplate injuries were selected to explore the methods of diagnosis and surgical treatment. All patients underwent examinations using radiography, CT, and MR imaging. Pain level of disc was determined through discography in each patient. The principal outcome judgments were pain and disability, and the efficacy of surgical treatment was assessed through the use of the visual analog scale (VAS) for pain and the Oswestry disability index (ODI) for functional recovery. All 21 patients with a diagnosis of back pain originating from endplate injuries according to discography were treated with anterior or posterior fusion surgery. The mean follow-up period was 3 years and 5 months (range, 2-6 years). Of the 21 patients, 20 (20/21) reported a disappearance or marked alleviation of low back pain and experienced a definite improvement in physical function. Statistically significant and clinically meaningful improvements in the VAS and ODI scores were obtained after treatment in the patients with chronic low back pain originating from the endplate injuries (P = 0.0001). The study suggests that discography and fusion surgery may be very effective methods for the diagnosis and treatment, respectively, of chronic back pain originating from the endplate injuries.

Efficacy of autologous iliac crest bone graft and bone morphogenetic proteins for posterolateral fusion of lumbar spine: a meta-analysis of the results

STUDY DESIGN

Meta analysis of randomized control trials.

OBJECTIVE

To evaluate the radiographic and clinical effectiveness of bone morphogenetic proteins (BMPs) within the context of posterolateral fusion of the lumbar spine (LS).

SUMMARY OF BACKGROUND DATA

Various bone graft substitutes have been used in the setting of posterolateral lumbar fusions. Recently, great interest has been shown in BMPs. Clinical trials have tested the efficacy of BMPs to iliac crest bone graft (ICBG) in posterolateral fusion procedures of the LS. A cumulative result of these studies would give more credit to the final conclusions.

METHODS

A systematic search of electronic databases, and references from eligible articles was conducted. Comparative studies reporting on the results of posterolateral fusion for treatment of degenerative disease of LS and including 2 treatment groups either ICBG (control group) or BMP (experimental group) for achievement of fusion were regarded eligible. A pooled estimate of effect size was produced using both random and fixed effect model.

RESULTS

Seven randomized control trials (n = 331 patients) and 1 prospective comparative study (n = 52 patients) were included in the present study. BMPs appeared more efficacious to ICBG in achieving solid fusion [relative risk (RR) = 0.42, 95% confidence interval (CI) = 0.28-0.61, P < 0.00001], but with significant heterogeneity (I = 42.5%). rBMP-2 was more efficacious to ICBG in promoting fusion (RR = 0.29, 95% CI = 0.18-0.47, P < 0.00001), whereas rhBMP-7 (osteogenic protein-1) appeared equivalent to ICBG in that respect (RR = 1.17, 95% CI = 0.54-2.54, P = 0.70). Patients treated with BMPs had a shorter hospitalization (by 1.03 days, 95% CI = 0.61-1.45 days) compared with those that were treated with ICBG. BMPs appeared more efficient in instrumented than noninstrumented posterolateral fusions.

CONCLUSION

Although the radiographic results appeared better in the group of BMPs, the exact role of type, dose and carrier of BMPs and the cost-effectiveness of their use need further clinical delineation.

Disc height reduction in adjacent segments and clinical outcome 10 years after lumbar 360 degrees fusion

Adjacent segment degeneration (ASD) is discussed to impair long-term outcome after lumbar interbody fusion. Nevertheless the amount and origin of degeneration and its clinical relevance remain unclear. Only little data is published studying quantitative disc height reduction (DHR) as indicator for ASD in long-term follow-up. Forty patients (23 men, 17 women) (group 1: degenerative disc disease, n = 27; group 2: lytic spondylolisthesis, n = 13) underwent lumbar 360 degrees instrumentation and fusion between 1991 and 1997. Preoperative and follow-up lateral lumbar radiographs were studied. Disc heights of first and second cephalad adjacent segments were measured by Farfan's technique and Hurxthal's technique modified by Pope. Clinical outcome was studied using Oswestry disability index (ODI) and visual analogue scale (VAS). Age, gender, prior surgery, fusion rate and number of fusion levels were investigated as potential factors affecting the outcome. Mean follow-up was 114 (72-161) months. Clinical outcome showed an improvement of 44.6% in ODI and 43.8% in VAS with a tendency towards better results in group 2. Fusion rate was 95%. Disc height of the first cephalad adjacent segment in all patients was reduced by on average 21% (Farfan, P < 0.001) and 19% (Pope, P < 0.001), respectively, and that of the second adjacent level by on average 16% (Farfan, P < 0.001) and 14% (Pope, P < 0.001), respectively. A tendency towards more disc height reduction (DHR) in the degenerative group was observed. Advanced age correlated with advanced DHR (P < or = 0.003, r = 0.5). Multiple level fusion led to a more pronounced DHR than 1-level fusion (P = 0.028). There was a tendency towards more DHR in the first adjacent disc compared to the second. Gender, prior surgery of the fused segment and fusion level did not affect the amount of DHR. There was no correlation between the clinical outcome and DHR. Lumbar fusion is associated with DHR of adjacent discs. This may be induced by additional biomechanical stress, ongoing degeneration affecting the lumbar spine and advancing age. However, clinical outcome is not correlated with adjacent DHR.

Computed tomography–guided percutaneous facet screw fixation in the lumbar spine

✓ The authors describe a new minimally invasive technique for posterior supplementation using percutaneous trans-laminar facet screw (TFS) fixation with computed tomography (CT) guidance. Oblique axial images were used to determine facet screw fixation sites. After the induction of local anesthesia and conscious sedation, a guide pin was inserted and guided with a laser mounted on the CT gantry. Cannulated TFSs were placed via a percutaneous approach. From December 2002 to August 2003, 18 patients underwent CT-guided TFS. In 17 of these patients this procedure was supplementary to anterior lumbar interbody fusion, which had been performed several days earlier; in the remaining patient, CT-guided TFS fixation was undertaken as the primary therapy. Twelve patients had painful degenerative disc disease or unstable degenerative spondylolisthesis, three had infections, and three had deformities. All screws were inserted accurately and there were no complications. This new minimally invasive surgical technique may offer an alternative to pedicle screw fixation as a method of posterior supplementation.

Intradiscal methylene blue injection for the treatment of chronic discogenic low back pain

This article was a preliminary report of prospective clinical trial of a group of patients with chronic discogenic low back pain who met the criteria for lumbar interbody fusion surgery but were treated instead with an intradiscal injection of methylene blue (MB) for the pain relief. Twenty-four patients with chronic discogenic low back pain underwent diagnostic discography with intradiscal injection of MB. The principal criteria to judge the effectiveness included alleviation of pain, assessed by visual analog scale (VAS), and improvement in disability, as assessed with the Oswestry Disability Index (ODI) for functional recovery. The mean follow-up period was 18.2 months (range 12-23 months). Of the 24 patients, 21 (87%) reported a disappearance or marked alleviation of low back pain, and experienced a definite improvement in physical function. A statistically significant and clinically meaningful improvement in the changes in the ODI and the VAS scores were obtained in the patients with chronic discogenic low back pain (P=0.0001) after the treatment. The study suggests that the injection of MB into the painful disc may be a very effective alternative for the surgical treatment of chronic discogenic low back pain.

Lumbar fusion outcomes in Washington State workers' compensation

STUDY DESIGN

Retrospective population-based cohort study.

OBJECTIVE

To evaluate the influence of lumbar intervertebral fusion devices on clinical and disability outcomes among Washington State compensated workers with chronic back pain.

SUMMARY OF BACKGROUND DATA

The efficacy of lumbar fusion for chronic low back pain remains controversial. Recent randomized controlled trials have shown results of fusion to be equivalent to those of structured exercise and cognitive intervention. Lumbar fusion rates, however, continue to increase nationally, fueled, in part, by introduction of new fusion devices, including intervertebral cages in 1996. It is not known whether these newer devices have improved outcomes, and particularly in compensated workers.

METHODS

In this population-based retrospective cohort study, we identified Washington State injured workers who underwent lumbar fusion between 1994 and 2001 from Washington State Workers' Compensation system administrative database. All the data for this study were obtained from either the claims or medical bill payment databases. Multiple logistic regression analyses were used to examine the association between the surgical technique (interbody cages and/or instrumentation) and the risk of disability, reoperation, and complications following lumbar fusion.

RESULTS

Among the 1,950 eligible subjects, fusions with cages increased from 3.6% in 1996 to 58.1% in 2001. Overall disability rate at 2 years after fusion was 63.9%, reoperation rate 22.1%, and rate for other complications 11.8%. Use of cages or instrumentation was associated with increased complication risk compared with bone-only fusions without improving disability or reoperation rates. Legal, work-related, and psychologic factors predicted worse disability. Discography and multilevel fusions predicted greater reoperation risk. Degenerative disc disease and concurrent decompression procedures predicted lower reoperation risk.

CONCLUSIONS

Use of intervertebral fusion devices rose rapidly after their introduction in 1996. This increased use was associated with an increased complication risk without improving disability or reoperation rates.

Imaging of the postoperative spine

Spinal instrumentation techniques have expanded dramatically during the past several decades, but the search for the perfect operative approach and fixation system continues. Fixation devices are designed for the cervical, thoracic, lumbar, and sacral segments using anterior, posterior, transverse, videoarthroscopic, and combined approaches. In most cases, bone grafting also is performed, because instrument failure occurs if solid bony fusion is not achieved. Radiologists must understand the operative and instrumentation options. Knowledge of expected results, appearance of graft material, and different forms of instrumentation is critical for evaluating position of implants and potential complications associated with operative approaches and spinal fixation devices.

Mid-term and long-term follow-up data after placement of the Graf stabilization system for lumbar degenerative disorders

Object

The Graf pedicle screw and ligament device is designed to provide flexible stabilization to prevent abnormal spinal movement. The purpose of this study was to investigate radiographic and clinical outcomes during a minimal 5-year follow-up period.

Methods

Between 1991 and 1997, 43 consecutive patients (whose mean age was 61 years) with lumbar degenerative disease underwent decompression and stabilization in which the Graf system was placed. Data were available for 31 patients who attended follow up for the minimal 5-year period. In a retrospective review, the authors assessed measurements on radiographs, clinical results (using Japanese Orthopaedic Association [JOA] Scale scores), and low-back pain (using a visual analog scale [VAS] score), preoperatively and postoperatively at 1, 3, 5, and/or 10 years. Radiographic measurements included sagittal and frontal range of motion (ROM), regional lordosis, and posterior disc height as well as the extent of degenerative spondylolisthesis.

Final follow-up JOA and VAS scores were significantly better than preoperative scores. Sagittal and frontal ROM was significantly reduced at 1 and 5 years, respectively, compared with preoperative values, and a gradual reduction persisted throughout the follow-up period. Compared with its preoperative status, the disc height ratio (adjacent segments to the operated level) was reduced 5 years after surgery. A significant inhibition of the vertebral slippage was detected only in the flexion position.

Conclusions

Analysis of these data indicated that the Graf system eventually leads to successful fusion, suggesting the presence of stability in all three dimensions. The use of the Graf system should continue to be evaluated as an alternative device in the treatment of lumbar degenerative disease.

Biomechanical comparison between fusion of two vertebrae and implantation of an artificial intervertebral disc

Surgical treatments for lower back pain can be distributed into two main groups: fusion (arthrodesis) and disc replacement (arthroplasty). The objective of this study was to compare, under severe loading conditions, the biomechanics of the lumbar spine treated either by fusion or total disc replacement (TDR). A three-dimensional model of a two-level ligamentous lumbar segment was created and simulated through static analyses with the finite-element method (FEM) software ABAQUS. The model was validated by comparing mobility, pressure on the facets, force in the ligaments, maximum stresses, disc bulge, and endplate deflection with measured data given in the literature. The FEM analysis predicted that the mobility of the model after arthrodesis on the upper level was reduced in all rotational degrees of freedom by an average of approximately 44%, relative to healthy normal discs. Conversely, the mobility of the model after TDR on the upper level was increased in all rotational degrees of freedom by an average of approximately 52%. The level implanted with the artificial disc showed excessive ligament tensions (greater than 500 N), high facet pressures (greater than 3 MPa), and a high risk of instability. The mobility and the stresses in the level adjacent to the arthroplasty were also increased. In conclusion, the model for an implanted movable artificial disc illustrated complications common to spinal arthroplasty and showed greater risk of instability and further degeneration than predicted for the fused model. This modeling technique provides an accurate means for assessing potential biomechanical risks and can be used to improve the design of future artificial intervertebral discs.

Clinical outcomes of 3 fusion methods through the posterior approach in the lumbar spine

STUDY DESIGN

This prospective randomized study compared 3 fusion methods: posterolateral fusion (PLF), posterior lumbar interbody fusion (PLIF), and PLIF combined with PLF (PLF+PLIF).

OBJECTIVES

To compare the outcomes of the 3 fusion methods and find a useful fusion method.

SUMMARY OF BACKGROUND DATA

Many studies have shown clinical results, advantages, and postoperative complications of each fusion method, but few have compared the 3 fusion methods prospectively.

METHODS

A total of 167 patients who underwent 1 or 2-level fusion surgery because of degenerative lumbar disease from January 1996 to September 2000 were studied. Minimum follow-up was 3 years. The patients were randomized into 1 of 3 treatment groups: group 1 (PLF; n = 62); group 2 (PLIF; n = 57); and group 3 (PLF+PLIF; n = 48). A visual analog scale, the Oswestry Disability Questionnaire, and Kirkaldy-Willis criteria were used to measure low back pain, leg pain, and disability. For radiologic evaluation, disc height, lumbar lordosis, segmental angle, and bone union were examined. Postoperative complications were also analyzed.

RESULTS

At the last follow-up, good or excellent results were obtained in 50 cases of PLF (80.7%), 50 cases of PLIF (87.8%), and 41 cases of PLF+PLIF (85.5%). No statistical differences were found among the 3 groups (P = 0.704). All methods indicated significant improvement in the disc height (P < 0.05), with PLF having the highest loss in disc height. Lumbar lordosis and segmental angle increased significantly, and improvement of the segmental angle in the 3 fusion methods had statistically significant differences. The nonunion rates at the last follow-up in the 3 fusion groups were not statistically significant, with 8% in group 1, 5% in group 2, and 4% in group 3 (P > 0.05). Complications included deep infection in 3 cases, transient nerve palsy in 4, permanent nerve palsy in 1, and donor site pain in 6.

CONCLUSIONS

No significant differences in clinical results and union rates were found among the 3 fusion methods. PLIF had better sagittal balance than PLF. PLIF without PLF had advantages of the elimination of donor site pain, shorter operating time, and less blood loss.

Do We Need Biomarkers for Disc Degeneration?

Disc degeneration plays a major role in this country's medical, social and economic structure. The life-time prevalence of low back pain, which has disc degeneration as its cause, is about 80% in the general population. It is a primary cause of disability and estimated costs related to low back disorders exceed $100 billion per year in the U.S. alone. Biomarkers are becoming increasingly important as indicators of the presence of disease, and in evaluating outcomes during clinical treatment. Cell-based biologic therapies which are currently being developed to treat disc degeneration are going to be most efficacious when applied to the early stages of disc disease. In this article we ask: 1) Whether there are existing biomarkers which could play a role in detecting early stages of disc degeneration, and 2) Highlight exciting potentials in future biomarker screening for disc degeneration.

Temporary external transpedicular fixation of the lumbosacral spine: a prospective, longitudinal study in 330 patients

STUDY DESIGN

In this study, 330 patients with incapacitating low back pain underwent temporary external transpedicular fixation (TETF) of the lumbosacral spine in a prospective trial.

OBJECTIVE

To evaluate TETF as a test for selecting suitable candidates for segmental spinal fusion.

SUMMARY OF BACKGROUND DATA

Few studies regarding TETF have been published, and contradictory results concerning predictive value and morbidity were reported.

METHODS

All patients were tested with the external fixator in two different positions: fixation and nonfixation. Before and during the test and at follow-up examination, pain was assessed on a Visual Analogue Scale (VAS). The TETF test was considered to be positive if the VAS score in the fixation state was 30 or more points lower than in the nonfixation state. Hence, a positive test would imply the decision to perform segmental lumbosacral fusion. When the reduction was less than 30 points, the test was negative. Individual pain reduction and working capacity were taken as measure of outcome.

RESULTS

Most of the patients in this study (62%) underwent spinal surgery previously. The positive and negative TETF groups were quite similar, but a large within-group variation was found. Within the fusion group of 123 patients, improvement in VAS scores and improvement in working capacity were not significantly better for the positive TETF group in comparison with the negative TETF group.

CONCLUSION

In this heterogeneous group of chronic patients with low back pain, TETF of the spine (including a placebo trial) does not appear to be of value in selecting suitable candidates for spinal fusion.

The ProDisc Artificial Disc: Insertion Technique

The ProDisc artificial lumbar disc was designed for use in treatment of degenerative lumbar disease. The disc is implanted using an anterior approach to the lumbar spine with the assistance of intraoperative fluoroscopy. A variety of insertion instruments guide the surgeon through this process. The disc is implanted via an anterior approach, generally retroperitoneally but on occasion transperitoneally. The different approaches and insertion technique are described in this article.

Etiologies of failed back surgery syndrome

STUDY DESIGN

Retrospective chart review.

OBJECTIVE

To report the epidemiologic data of nonsurgical and surgical etiologies of failed back surgery syndrome (FBSS) from two outpatient spine practices.

SUMMARY OF BACKGROUND DATA

FBSS has been offered as a diagnosis, but this is an imprecise term encompassing a heterogeneous group of disorders that have in common pain symptoms after lumbar surgery. The current literature primarily diagnoses for the various etiologies of FBSS from a surgical perspective. To our knowledge, there is no study that investigates the myriad of surgical and nonsurgical diagnoses from a nonsurgical perspective.

METHODS

Specific inclusion and exclusion criteria were developed for a list of 42 nonsurgical and surgical differential diagnoses of FBSS. The determination of which category, surgical or nonsurgical, each diagnosis was placed into depended upon the categorization of those diagnoses in previously published literature on FBSS. Each of the authors reviewed the definitions, and they came to a unanimous agreement on each diagnosis' inclusion and exclusion criteria. Data extraction was then carried out in each of the two involved institutions by using the key words discectomy, laminectomy, and fusion to identify all the patients who had any combination of low back, buttock, or lower extremity pain after lumbar discectomy surgery. These charts were then individually reviewed to extract epidemiologic data.

RESULTS

A total of 267 charts were reviewed. One hundred and ninety-seven (197) charts had a complete workup. Of these, 11 (5.6%) had an unknown etiology, and 186 had a known diagnosis. Twenty-three (23) various diagnoses were identified. There was approximately an equal distribution between the incidences of nonsurgical and surgical diagnoses; 44.4% had nonsurgical diagnoses and 55.6% had surgical diagnoses. The most common diagnoses identified were spinal stenosis, internal disc disruption syndrome, recurrent/retained disc, and neural fibrosis.

CONCLUSION

FBSS is a syndrome consisting of a myriad of surgical and nonsurgical etiologies. Approximately one half of FBSS patients have a surgical etiology. Approximately 95% of patients can be provided a specific diagnosis.

Low-Grade Isthmic Spondylolisthesis Treated with Instrumented Posterior Lumbar Interbody Fusion in U.S. Servicemen

PURPOSE

The existing literature lacks a functional outcomes study addressing instrumented posterior lumbar fusion surgery for isthmic spondylolisthesis in physically active patients. Presently, spinal surgeons can provide only anecdotal advice when discussing operative outcomes with these patients. This is a nonrandomized analysis of consecutive military servicemen treated operatively for chronic back pain and low-grade isthmic spondylolisthesis with single-level lumbar disc degeneration with emphasis on functional outcomes. The purpose was to evaluate patient-assessed function/pain/satisfaction and military job performance in U.S. servicemen treated with posterior lumbar interbody fusion (PLIF).

METHODS

Thirty consecutive U.S. military servicemen with chronic low back pain and low-grade lumbar isthmic spondylolisthesis were referred to the same surgeon at a military treatment facility. All servicemen were treated operatively with instrumented PLIF using autogenous iliac crest bone graft, one or two nonthreaded interbody cages (Brantigan or Harms), and a four-pedicle screw/rod construct. A concomitant bilateral posterolateral fusion was performed in all 30 cases. The average follow-up time was 15 months (range 12-48 months). Twenty-five of the 30 servicemen completed a functional outcomes questionnaire (American Academy of Orthopaedic Surgeons/Scoliosis Research Society) with emphasis on pre- and posttreatment function, pain, and satisfaction. The servicemen were also evaluated using standard military job performance parameters.

RESULTS

Three of the 30 servicemen (10%) requested and received a disability discharge from the military for back pain that continued throughout the postoperative period and prevented return to military duty. An additional 8 of the original 30 soldiers (27%) required some form of permanent physical activity limitation (situps/pushups/running/lifting) to permit their return to military duty, and 19 of 30 (63%) soldiers were able to return to full and unrestricted military duty after surgery. Those soldiers who were able to return to unrestricted military duty (n = 19) did so at an average of 6 months post treatment (range 2-16 months). Of the soldiers who were able to return to military duty, 21 of 30 (70%) were able to complete the posttreatment military physical fitness test at an average of 8 months postoperatively (range 2-32 months). No significant differences were observed between premorbid and postsurgical physical fitness test scores. There was a trend toward lower postsurgical scores. Complications included dural tear (n = 4), unilateral transient lower extremity paresthesia (n = 1), and wound seroma requiring reoperation (n = 1).

CONCLUSIONS

In this nonrandomized study of 30 U.S. servicemen with chronic low back pain, low-grade isthmic spondylolisthesis, and single-level lumbar disc degeneration, instrumented PLIF surgery was associated with a high rate of return to functional military duty. Outcomes with respect to posttreatment pain, function, and satisfaction were high in patients treated with instrumented PLIF.

Transforaminal lumbar interbody fusion: a safe technique with satisfactory three to five year results

The unilateral transforaminal approach for lumbar interbody fusion as an alternative to the anterior (ALIF) and traditional posterior lumbar interbody fusion (PLIF) combined with pedicle screw instrumentation is gaining in popularity. At present, a prospective study using a standardized tool for outcome measurement after the transforaminal lumber interbody fusion (TLIF) with a follow-up of at least 3 years is not available in the current literature, although there have been reports on specific complications and cost efficiency. Therefore, a study of TLIF was undertaken. Fifty-two consecutive patients with a minimum follow-up of 3 years were included, with the mean follow-up being 46 months (36--64). The indications were 22 isthmic spondylolistheses and 30 degenerative disorders of the lumbar spine. Thirty-nine cases were one-level, 11 cases were two-level, and two cases were three-level fusions. The pain and disability status was prospectively evaluated by the Oswestry disability index (ODI) and a visual analog scale (VAS). The status of bony fusion was evaluated by an independent radiologist using anterior-posterior and lateral radiographs. The operation time averaged 173 min for one-level and 238 min for multiple-level fusions. Average blood loss was 485 ml for one-level and 560 ml for multiple-level fusions. There were four serious complications registered: a deep infection, a persistent radiculopathy, a symptomatic contralateral disc herniation and a pseudarthrosis with loosening of the implants. Overall, the pain relief in the VAS and the reduction of the ODI was significant (P<0.05) at follow-up. The fusion rate was 89%. At the latest follow-up, significant differences of the ODI were neither found between isthmic spondylolistheses and degenerative diseases, nor between one- and multiple-level fusions. In conclusion, the TLIF technique has comparable results to other interbody fusions, such as the PLIF and ALIF techniques. The potential advantages of the TLIF technique include avoidance of the anterior approach and reduction of the approach related posterior trauma to the spinal canal.

The pathogenesis of discogenic low back pain

Discogenic low back pain is a common cause of disability, but its pathogenesis is poorly understood. We collected 19 specimens of lumbar intervertebral discs from 17 patients with discogenic low back pain during posterior lumbar interbody fusion, 12 from physiologically ageing discs and ten from normal control discs. We investigated the histological features and assessed the immunoreactive activity of neurofilament (NF200) and neuropeptides such as substance P (SP) and vasoactive-intestinal peptide (VIP) in the nerve fibres.

The distinct histological characteristic of the painful disc was the formation of a zone of vascularised granulation tissue from the nucleus pulposus to the outer part of the annulus fibrosus along the edges of the fissures. SP-, NF- and VIP-immunoreactive nerve fibres in the painful discs were more extensive than in the control discs. Growth of nerves deep into the annulus fibrosus and nucleus pulposus was observed mainly along the zone of granulation tissue in the painful discs. This suggests that the zone of granulation tissue with extensive innervation along the tears in the posterior part of the painful disc may be responsible for causing the pain of discography and of discogenic low back pain.

Posterior augmentation of an anterior lumbar interbody fusion: minimally invasive fixation versus pedicle screws in vitro

STUDY DESIGN

An in vitro biomechanical comparison of four posterior fixation techniques in the setting of an anterior lumbar interbody fusion (ALIF).

OBJECTIVE

To compare the initial stability, in terms of range of motion and neutral zone, provided by pedicle screws, facet screws, translaminar facet screws, and H-graft plus interspinous cables in the presence of an anteriorly placed femoral ring allograft.

SUMMARY OF BACKGROUND DATA

Pedicular fixation has been used to increase ALIF fusion rates but has also been linked with increased morbidity. Alternative posterior fixation options are available, but comprehensive biomechanical comparisons of these techniques do not exist. METHODS.: Twelve cadaveric lumbar motion segments were loaded to 5 Nm in unconstrained flexion-extension, lateral bending, and axial torsion. Specimens were tested intact, after ALIF, and after applying pedicle screws, translaminar screws, facet screws, and H-graft plus cables. The resulting neutral zones and ranges of motion were measured.

RESULTS

The mean (+/-SEM) range of motion for each construct in flexion-extension was as follows: intact: 6.39 degrees (+/-0.47 degrees); ALIF alone: 3.31 degrees (+/-0.22 degrees); (ALIF+) pedicle screws: 0.6 degrees (+/-0.06 degrees); facet screws: 0.75 degrees (+/-0.12 degrees); translaminar screws: 0.61 degrees (+/-0.09 degrees); and H-graft: 1.74 degrees (+/-0.26 degrees). Pedicle, translaminar facet, and facet screws significantly decreased range of motion and neutral zone compared to ALIF alone in flexion-extension, lateral bending, and axial torsion (all at P < 0.04, except translaminar screws in torsion neutral zone where P = 0.09). H-graft decreasedflexion-extension range of motion and neutral zone only (P < 0.01) and resulted in a significantly greater neutral zone than pedicle and facet screws in torsion and lateral bending neutral zones (P < 0.03).

CONCLUSIONS

In the ALIF setting, facet screw and translaminar screw techniques, which may be associated with less morbidity than pedicle screws clinically, provided initial posterior stabilization similar to pedicular fixation in this in vitro study.

Results after anterior-posterior lumbar spinal fusion: 2-5 years follow-up

Between 1991 and 1998, we treated 72 patients with fusion of the lumbar spine using posterior pedicle screw fixation followed by anterior retroperitoneal insertion of a titanium cage filled with autogenous bone graft. All patients had chronic low back pain after failed conservative treatment. We were able to review 54 patients with a mean follow-up of 51 (24-97) months. The mean Oswestry low back pain disability score improved from 56.8 preoperative to postoperative 29.8 and 31.2 at follow-up (p<0.05). The mean visual analog pain intensity scale improved from 8.3 to 4.0 postoperative and 4.8 at follow-up (p<0.05). The results demonstrate that circumferential lumbar fusion can be an option for the treatment of chronic low back pain.

The influence of personality traits on the subjective outcome of operative hallux valgus correction

We studied prospectively the influence of personality traits on the subjective outcome of a chevron osteotomy in 42 patients with hallux valgus. The mean age of patients was 48.3 (20-70) years. Personality traits were evaluated by the means of the Freiburg Personality Inventory (FPI-R). Three months postoperatively 37 patients were satisfied, and five patients not satisfied with the operative procedure. The preoperative AOFAS Score improved from an average of 48.7 (30-65) points to 87.9 (50-100) points. A comparison of satisfied and dissatisfied patients revealed statistically significant differences in the personality traits aggressiveness (p=0.003), extraversion (p=0.001) and health worries (p=0.04). The postoperative hallux valgus angle was 12.2+/-7.8 degrees and 13.4+/-8.3 degrees (p=0.74) among satisfied and not satisfied patients, respectively, and the intermetatarsal angle (I-II) was 7.4+/-2.5 degrees and 7.6+/-4 degrees (p=0.89), respectively. The results suggest that the patient's subjective result after the operative correction may be influenced by some individual, personality profiles.

Prospective Assessment of Outcomes Improvement Following Fusion for Low Back Pain

BACKGROUND

This prospective study was performed to improve the quality of outcomes data in patients undergoing spinal fusion for low back pain. There is an accepted deficiency of this form of outcomes assessment in the literature. The aim was to determine the effectiveness of the surgical procedure in terms of patient satisfaction, outcome scores, and third-party measures.

METHODS

The measures of outcomes assessment included patient satisfaction, pain scores, low back outcome and Prolo scores, medication use, and employment status. Data collection was prospective prior to and at final follow-up. Eighty percent of 35 patients were followed for a mean of 31 months.

RESULTS

Patient satisfaction was 71%; however, only 28.6% of patients followed achieved good or excellent low back outcome scores. Yet significant improvement occurred: 46.4% achieved a good or excellent outcome using the Prolo score. There was a 75% reduction in medication usage, and 75% of nonworking compensation patients returned to gainful employment. Patient satisfaction was markedly higher than improvement measured by the outcome scores. Dramatic improvements in medication usage and return to work were achieved, despite less than spectacular outcome scores.

CONCLUSIONS

These findings support cautious use of posterior spinal fusion. Patients must appreciate improvement rather than normality as a realistic aim.

Posterior lumbar interbody fusion using local facet joint autograft and pedicle screw fixation

STUDY DESIGN

This is a retrospective study of 42 patients having lumbar degenerative disease or spondylolytic spondylolisthesis treated by posterior lumbar interbody fusion (PLIF) using local autogenous facet joint graft and pedicle screw fixation with an average follow-up time of 8.5 years.

OBJECTIVES

To evaluate the radiographic and clinical results of patients treated with PLIF using adjacent facet joint autograft and pedicle screw internal fixation.

SUMMARY OF BACKGROUND DATA

Some goals of spinal surgery have been achieved by interbody arthrodesis using a posterior approach popularized by Cloward. However, significant problems including bone graft collapse, resorption, nonunion, persistent neurologic compression, and iliac crest donor complication using the classic PLIF remain. There are few reports describing the results of a PLIF by total facet joint excision.

METHODS

Forty-two patients (average, 53.2 years) treated at our institution with PLIF by total facetectomy were followed for an average period of 8.5 years. The changes in the Japanese Orthopedic Association score, the recovery rate, complications, and radiographic findings were evaluated.

RESULTS

Good radiographic fusion (92.9%) and clinical results (postoperative recovery rate of 76% in the Japanese Orthopedic Association score) were achieved by PLIF using local facet joint autograft and pedicle screw fixation in treating patients with debilitating lumbar degenerative disease. The complications related to the operative procedure occurred in three patients of delayed union.

CONCLUSIONS

For lumbar degenerative diseases with osteophytic changes of facet joints, PLIF using pedicle screw fixation and local autogenous bones obtained from facet excision may be justified as a treatment opinion. The procedure as described offers advantages for spinal surgery when PLIF is warranted.

Assessing observational studies of spinal fusion and chemonucleolysis

STUDY DESIGN

Literature review and survey of spine surgeons.

OBJECTIVES

To identify reasons for variation in results among observational studies of spinal surgery.

SUMMARY AND BACKGROUND DATA

Orthopedic treatments are often evaluated by observational studies rather than randomized controlled trials. The value of observational studies is debated.

METHODS

A literature search was performed to find several observational studies that compared the same spinal surgeries. Possible confounders for these studies were identified by a survey of spinal surgeons. Study characteristics from these articles were tested for an association with study results.

RESULTS

Most observational studies were case series. Articles studied in depth included 20 evaluating chemonucleolysis and 14 evaluating spinal arthrodesis for patients who had herniated disc or spinal stenosis. For each treatment comparison, results varied from strongly favoring one treatment to strongly favoring the other. Apparent causes of the variation were patient selection criteria, the choice of outcome measure, and follow-up rate. Few studies reported on the potential confounders identified by physician surveys, and only one study used statistical methods to reduce the influence of confounding.

CONCLUSIONS

The results suggest that review of several comparable observational studies may help evaluate treatment, identify patient types most likely to benefit from a give treatment, and provide information about study features that can improve the design of subsequent observational or randomized controlled studies. The potential of comparative observational studies has not been realized because of current inadequacies in their design, analysis, and reporting.