Functional and radiological outcomes of semi-rigid dynamic lumbar stabilization adjacent to single-level fusion after 2 years

Objective

To prospectively evaluate the functional and radiological outcomes of Isobar semi-rigid dynamic posterior stabilization adjacent to single-level fusion up to and including 24 months postoperatively.

Method

A prospective follow-up for 24 months of 36 patients who underwent posterior Isobar dynamic stabilization due to single-level degenerative lumbar discopathy and instability (DLDI) with mild adjacent level degeneration, with collection of functional [visual analog scale (VAS) and Oswestry Disability Index (ODI)] and radiological data (resting, functional X-rays and MRI).

Results

Functional outcomes at 24 months showed significant improvement in mean VAS score by 38.9 points (P < 0.01) and ODI by 22.4 points (P < 0.01). Compared with data preoperatively, disc height at the index and adjacent levels and intervertebral angle (IVA) at the index level showed a slight decreasing trend at each follow-up (P > 0.05), while IVA at the adjacent level showed a slight increasing trend (P > 0.05). Range of motion averaged 2.84° at the index level and remained unchanged at the adjacent level (P > 0.05). The mean Pfirrmann score changed from 2.86 preoperatively to 2.92 at 24 months postoperatively at the index level (P > 0.05), and from 1.92 preoperatively to 1.96 at 24 months postoperatively at the adjacent level (P > 0.05). No reoperation, loosening of screws or infection was recorded.

Conclusions

Patients with single-level DLDI and mild adjacent level degeneration treated with Isobar stabilization show a clinical improvement after 2 years. However, disc degeneration at the index and adjacent levels seems to continue despite using semi-rigid dynamic stabilization.     

Radiological factors affecting functional outcome after the implantation of BDYN™ dynamic stabilization system for low-grade lumbar degenerative spondylolisthesis

BackgroundThe objectives of this study are to identify radiological factors associated with good functional outcomes after the implantation of BDYN™ dynamic stabilization system in the setting of painful low-grade degenerative lumbar spondylolisthesis (DLS).Material and methodsIn this monocentric, retrospective study, we followed 50 patients, a 5-years period, with chronic lower back pain, radiculopathy and/or neurogenic claudication evolving for at least one year that failed conservative treatment. All patients presented low-grade DLS and underwent lumbar dynamic stabilization. Radiological and clinical outcomes were assessed preoperatively and 24 months after surgery. Functional evaluation was based on the Oswestry Disability Index (ODI), the Numerical Rating Scale (NRS), and the Walking Distance (WD). Radiological analysis was based on lumbar X-rays and MRI parameters. Patients were divided into two groups according to the reduction in the postoperative ODI score (more or less than 15 points), and statistical analysis was performed between both groups to find predictive radiological factors for a satisfying functional outcome.ResultsClinically, 80% (40 patients) had a satisfying functional result, and 20% (10 patients) were considered having a poor outcome according to the ODI score. Radiologically, the loss in segmental lordosis was statistically associated with bad functional outcomes (18° for ODI decrease > 15 versus 11° for ODI decrease < 15). There is also a tendency showing that a higher Pfirmann disc signal grade (grade IV) and a severe canal stenosis according to Schizas classification (grade C & D) are predictive of a poor clinical result, but that must be confirmed in future studies.ConclusionsBDYN™ appears safe and well-tolerated. This new device should be effective for the treatment of patients with low-grade DLS. It provides significant improvement in terms of daily life activity and pain. Moreover, we have been able to deduce that a kyphotic disc is associated with a bad functional outcome after BDYN™ device implantation. It may represent a contraindication for the implantation of such DS device. Moreover, it seems that it is better to implant BDYN™ in DLS with mild or moderate disc degeneration and canal stenosis.     

Which procedure is better for lumbar interbody fusion: anterior lumbar interbody fusion or transforaminal lumbar interbody fusion?

Introduction

Both anterior lumbar interbody fusion (ALIF) and transforaminal lumbar interbody fusion (TLIF) surgeries are performed to obtain a solid fusion to treat lumbar spondylosis. This systematic review investigated whether surgical complications, nonfusion rate, radiographic outcome, and clinical outcome of ALIF were significantly different from those of TLIF.

Method

A computerized search of the electronic databases MEDLINE was conducted. Only therapeutic studies with a prospective or retrospective comparative design were considered for inclusion in the present investigation. Two reviewers independently extracted relevant data from each included study. Statistical comparisons were made when appropriate.

Results

Nine studies were determined to be appropriate for the systematic review, and all studies were retrospective comparative studies. Blood loss and operative time in ALIF was greater than in TLIF. There was no significant difference in the complication rate between ALIF and TLIF. The restoration of disc height, segmental lordosis, and whole lumbar lordosis in ALIF was superior to TLIF. However, clinical outcomes in ALIF were similar with TLIF, and there was no significant difference in nonfusion rate between the two techniques. Costs of ALIF were greater than those of TLIF.

Conclusion

Clinical outcomes and nonfusion rate in ALIF were similar to TLIF. However, the restoration of disc height, segmental lordosis, and whole lumbar lordosis in ALIF were superior to those in TLIF, while blood loss, operative time, and costs in ALIF were greater than in TLIF.     

Shaving of the lumbar disk space—a new technique in lumbar nucleotomy

Summary A complete curettage of the intervertebral space using the common surgical instruments (forceps, sharp spoons) is not possible during nucleotomy because of the anatomic site and the shape of the instruments. An alternative technique—called shaving—is described, which enables a faster, more effective, and less traumatizing removal of free-floating, pulpy residue in the intervertebral space.

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Zusammenfassung Eine komplette Ausräumung des Bandscheibenzwischenraumes bei Nukleotomien ist mit dem gängigen Operationsinstrumentarium (Rongeure, scharfe Löffel) aus anatomischen Gründen und wegen der Geometrie des Instrumentariums nicht möglich. Eine neue Operationstechnik — das Shaving des Bandscheibenbinnenraumes — wird beschrieben. Mit dieser Technik ist eine schnellere, effektivere und weniger traumatische Entfernung von frei flotierendem, pulpösen Restmaterial im Intervertebralraum möglich.

     

Degenerative disorders of the lumbar spine Total disc replacement as an alternative to lumbar fusion?

Spinal fusion is accepted worldwide as a therapeutic option for the treatment of degenerative disorders of the lumbar spine. Because there are only few evidence-based data available supporting the usefulness of lumbar spinal fusion, its questionable benefit as well as the potential for complications are the reasons for an ongoing discussion.In recent years, total disc replacement with implants has emerged as an alternative treatment. Although early results are promising, there is still a lack of evidence-based data as well as of long-term results for this technology. This article gives a critical update on the implant systems currently in use (SB Charité, Prodisc II L, Maverick, Flexicore, Mobidisc), which all have to be considered as "first-generation" implants. Morphological and clinical sequelae of the different biomechanical properties, designs, and materials have not yet been sufficiently investigated. There is no international consensus on the indication spectrum and on the preoperative diagnosis of discogenic low back pain. The same is true for the (minimally invasive) surgical access strategies. Complication rates seem to be somewhat lower compared to spinal fusion techniques. There are no standardized revision concepts in cases of implant failure.Lumbar disc replacement has opened a new era in spinal surgery with a still unproven benefit for the patient. It is strongly recommended that these techniques should only be applied by experienced and well-trained spine surgeons. Until evidence-based data are available, all patients should be treated under scientific study conditions with close postoperative follow-up.     

Surgical stabilization of internal pneumatic stabilization? A prospective randomized study of management of severe flail chest patients

BACKGROUND: We compared the clinical efficacy of surgical stabilization and internal pneumatic stabilization in severe flail chest patients who required prolonged ventilatory support. METHODS: Thirty-seven consecutive severe flail chest patients who required mechanical ventilation were enrolled in this study. All the patients received identical respiratory management, including end-tracheal intubation, mechanical ventilation, continuous epidural anesthesia, analgesia, bronchoscopic aspiration, postural drainage, and pulmonary hygiene. At 5 days after injury, surgical stabilization with Judet struts (S group, n = 18) or internal pneumatic stabilization (I group, n = 19) was randomly assigned. Most respiratory management was identical between the two groups except the surgical procedure. Statistical analysis using two-way analysis of variance and Tukey's test was used to compare the groups. RESULTS: Age, sex, Injury Severity Score, chest Abbreviated Injury Score, number of rib fractures, severity of lung contusion, and Pao2/Fio2 ratio at admission were all equivalent in the two groups. The S group showed a shorter ventilatory period (10.8 +/- 3.4 days) than the I group (18.3 +/- 7.4 days) (p < 0.05), shorter intensive care unit stay (S group, 16.5 +/- 7.4 days; I group, 26.8 +/- 13.2 days; p < 0.05), and lower incidence of pneumonia (S group, 24%; I group, 77%; p < 0.05). Percent forced vital capacity was higher in the S group at 1 month and thereafter (p < 0.05). The percentage of patients who had returned to full-time employment at 6 months was significantly higher in the S group (11 of 18) than in the I group (1 of 19). CONCLUSION: This study proved that in severe flail chest patients, surgical stabilization using Judet struts has beneficial effects with respect to less ventilatory support, lower incidence of pneumonia, shorter trauma intensive care unit stay, and reduced medical cost than internal fixation. Moreover, surgical stabilization with Judet struts improved percent forced vital capacity from the early phase after surgical fixation. Also, patients with surgical stabilization could return to their previous employment quicker than those with internal pneumatic stabilization, even in those with the same severity of flail chest. We therefore concluded that surgical stabilization with Judet struts may be preferably applied to patients with severe flail chest who need ventilator support.     

Minimally invasive 360° instrumented lumbar fusion

A retrospective preliminary study was undertaken of combined minimally invasive instrumented lumbar fusion utilizing the BERG (balloon-assisted endoscopic retroperitoneal gasless) approach ¶anteriorly, and a posterior small-incision approach with translaminar screw fixation and posterolateral ¶fusion. The study aimed to quantify the clinical and radiological results using this combined technique. The traditional minimally invasive approach to the anterior lumbar spine involves gas insufflation and provides reliable access only to L5-S1 and in some cases L4-5. A gas-mediated approach yields many technical drawbacks to performing spinal surgery. A minimally invasive posterior approach involving suprafascial pedicle screw instrumentation has been developed, but without widespread use. Translaminar facet fixation may be a viable alternative to transpedicular fixation in a 360° instrumented fusion model. Past studies have shown open 360° instrumented lumbar fusion yields high arthrodesis rates. The study examined the cases of 46 patients who underwent successful 360° instrumented lumbar fusion using a combined minimally invasive approach. Anterior lumbar interbody fusion (ALIF) at one or two levels was performed through the BERG approach; a gasless retroperitoneal approach to the lumbar spine allowing the use ¶of standard anterior instrumentation. Posteriorly, all patients underwent successful decompression, translaminar fixation, and posterolateral fusion at one or two levels through ¶one small (2.5–5.0 cm) incision. Results showed mean hospital stay of 2.02 days; mean combined blood loss was 255 cc; and mean pain relief was 56%, with 75.5% of patients reporting good, excellent, or total pain relief. Forty-two of 46 patients (93.2%) achieved a solid fusion ¶24 months after surgery. A total of 47% of all patients working prior to surgery returned to work following surgery. The study showed that minimally invasive 360° instrumented lumbar fusion, when performed utilizing these approaches, yields a high rate of solid arthrodesis (93.3%), good pain relief, short hospital stays, low blood losses, accelerated rehabilitation, and a quick return to the workforce. The BERG approach offers technical advantages over the traditional gas-mediated laparoscopic approach to the anterior lumbar spine.     

Minimally invasive 360° instrumented lumbar fusion

A retrospective preliminary study was undertaken of combined minimally invasive instrumented lumbar fusion utilizing the BERG (balloon-assisted endoscopic retroperitoneal gasless) approach ¶anteriorly, and a posterior small-incision approach with translaminar screw fixation and posterolateral ¶fusion. The study aimed to quantify the clinical and radiological results using this combined technique. The traditional minimally invasive approach to the anterior lumbar spine involves gas insufflation and provides reliable access only to L5-S1 and in some cases L4-5. A gas-mediated approach yields many technical drawbacks to performing spinal surgery. A minimally invasive posterior approach involving suprafascial pedicle screw instrumentation has been developed, but without widespread use. Translaminar facet fixation may be a viable alternative to transpedicular fixation in a 360° instrumented fusion model. Past studies have shown open 360° instrumented lumbar fusion yields high arthrodesis rates. The study examined the cases of 46 patients who underwent successful 360° instrumented lumbar fusion using a combined minimally invasive approach. Anterior lumbar interbody fusion (ALIF) at one or two levels was performed through the BERG approach; a gasless retroperitoneal approach to the lumbar spine allowing the use ¶of standard anterior instrumentation. Posteriorly, all patients underwent successful decompression, translaminar fixation, and posterolateral fusion at one or two levels through ¶one small (2.5-5.0 cm) incision. Results showed mean hospital stay of 2.02 days; mean combined blood loss was 255 cc; and mean pain relief was 56%, with 75.5% of patients reporting good, excellent, or total pain relief. Forty-two of 46 patients (93.2%) achieved a solid fusion ¶24 months after surgery. A total of 47% of all patients working prior to surgery returned to work following surgery. The study showed that minimally invasive 360° instrumented lumbar fusion, when performed utilizing these approaches, yields a high rate of solid arthrodesis (93.3%), good pain relief, short hospital stays, low blood losses, accelerated rehabilitation, and a quick return to the workforce. The BERG approach offers technical advantages over the traditional gas-mediated laparoscopic approach to the anterior lumbar spine.     

Can decompression surgery relieve low back pain in patients with lumbar spinal stenosis combined with degenerative lumbar scoliosis?

Introduction

Decompression with fusion is usually recommended in patients with lumbar spinal stenosis (LSS) combined with degenerative lumbar scoliosis (DLS). However, elderly patients with LSS and DLS often have other comorbidities, and surgical treatment must be both safe and effective. The aim of this study was to investigate whether decompression surgery alone alleviates low back pain (LBP) in patients with LSS and DLS, and to identify the predictors of postoperative residual LBP.

Materials and methods

A total of 75 patients (33 males and 42 females) with a mean age of 71.8 years (range 53–86 years) who underwent decompression surgery for LSS with DLS (Cobb angle ≥ 10°) and had a minimum follow-up period of 1 year, were retrospectively reviewed using the Japanese Orthopaedic Association scoring system for the assessment of lumbar spinal diseases (JOA score). Radiographic measurements included coronal and sagittal Cobb angles, apical vertebral rotation (Nash-Moe method), and anteroposterior and lateral spondylolisthesis. Logistic regression analysis was performed to investigate the predictors of residual LBP after surgery.

Results

Forty-nine patients had preoperative LBP, of which 29 (59.1 %) experienced postoperative relief of LBP. Logistic regression analysis demonstrated that the degree of apical vertebral rotation on preoperative radiography was significantly associated with postoperative residual LBP (odds ratio, 8.16, 95 % confidence interval, 1.55–83.81, p = 0.011).

Conclusion

A higher degree of apical vertebral rotation may therefore be an indicator of mechanical LBP in patients with LSS and DLS. Decompression with fusion should be recommended in these patients.     

Pelvic incidence–lumbar lordosis mismatch results in increased segmental joint loads in the unfused and fused lumbar spine

Purpose

Symptomatic adjacent segment disease (ASD) has been reported to occur in up to 27 % of lumbar fusion patients. A previous study identified patients at risk according to the difference of pelvic incidence and lordosis. Patients with a difference between pelvic incidence and lumbar lordosis >15° have been found to have a 20 times higher risk for ASD. Therefore, it was the aim of the present study to investigate forces acting on the adjacent segment in relation to pelvic incidence–lumbar lordosis (PILL) mismatch as a measure of spino-pelvic alignment using rigid body modeling to decipher the underlying forces as potential contributors to degeneration of the adjacent segment.

Methods

Sagittal configurations of 81 subjects were reconstructed in a musculoskeletal simulation environment. Lumbar spine height was normalized, and body and segmental mass properties were kept constant throughout the population to isolate the effect of sagittal alignment. A uniform forward/backward flexion movement (0°–30°–0°) was simulated for all subjects. Intervertebral joint loads at lumbar level L3–L4 and L4–L5 were determined before and after simulated fusion.

Results

In the unfused state, an approximately linear relationship between sagittal alignment and intervertebral loads could be established (shear: 0° flexion r = 0.36, p < 0.001, 30° flexion r = 0.48, p < 0.001; compression: 0° flexion r = 0.29, p < 0.01, 30° flexion r = 0.40, p < 0.001). Additionally, shear changes during the transition from upright to 30° flexed posture were on average 32 % higher at level L3–L4 and 14 % higher at level L4–L5 in alignments that were clinically observed to be prone to ASD. Simulated fusion affected shear forces at the level L3–L4 by 15 % (L4–L5 fusion) and 23 % (L4–S1 fusion) more for alignments at risk for ASD.

Conclusion

Higher adjacent segment shear forces in alignments at risk for ASD already prior to fusion provide a mechanistic explanation for the clinically observed correlation between PILL mismatch and rate of adjacent segment degeneration.     

Modified technique of transforaminal lumbar interbody fusion for segmental correction of lumbar kyphosis: a safe alternative to osteotomies?

Background

Sagittal rebalancing of a fixated lumbar hypolordosis (kyphosis) is very important to gain satisfactory results. To correct a misalignment vertebral column resection or pedicle subtraction osteotomies are favored, disregarding the relatively high complication rates. The aim of this study was to evaluate the efficiency and safety of a new modified transforaminal lumbar fusion technique as an alternative.

Methods

We conducted a retrospective review (06/2011-06/2015 ) of a prospective database at an University hospital. Inclusion criteria were adult patients with a fixated lumbar hypolordosis and the need of monosegmental correction of more than 10° with an mTLIF. Exclusion criteria consisted of minor aged patients and polysegmental corrections. Study parameters were the perioperative complications and the achieved postsurgical lordosis. The follow up period was 6 months.

Results

A total of 11 patients could be included. The mean segmental lordosis was -2.3° ± 12.4° (range -22° to 14°) preoperative and 15.5° ± 10.5° (range 0° to 29°) postoperative. The degree of correction was 17° ± 5.7° in mean per treated segment (range 12° to 29°). No neurologic or vascular complications occurred. No substantial loss of correction or implant failure was noted during the 6-month follow-up.

Conclusion

The modified transforaminal lumbar fusion technique is a safe method to correct a fixated lumbar kyphosis. The potential of segmental correction is comparable to pedicle subtraction osteotomies but sparing potentially healthy segments.

     

Is laparoscopic approach to lumbar spine fusion worthwhile?

BACKGROUND: Laparoscopic lumbar spine fusion has been recently described. The aim of this study is to evaluate the safety and efficacy of this procedure for single- and multiple-level degenerative disc disease. METHODS: Twenty-four consecutive laparoscopic interbody lumbar fusions were evaluated prospectively (18 single-level were compared with 6 multiple-level procedures). Results of the laparoscopic multiple-level procedures were further compared with 12 open multiple-level operations. RESULTS: Twenty procedures were completed laparoscopically. The conversions were related to iliac vein lacerations (3 cases) and a mesenteric tear. Single-level cases had lower morbidity (22% versus 83%), shorter hospital stay (2 versus 10 days), and higher fusion rate (88% versus 50%) than multiple-level procedures. Overall results in the latter group were worse than in the matched open group. CONCLUSIONS: Laparoscopic single-level fusion (L5-S1) is safe and carries the benefits of minimal access surgery. Morbidity after multiple level approach is high, and this procedure cannot be advocated at this time.     

Degenerative lumbar spinal stenosis—results of expansive laminoplasty

Expansive laminoplasty, a procedure used more and more often for cervical myelopathy, was carried out in patients with lumbar spinal stenosis in the Department of Orthopaedics, Paraplegia, Physical Medicine and Rehabilitation of our institute. Twenty-five such clinico-radiologically proven cases were operated upon. For radiological evaluation, computed tomography (CT) was used. Expansive laminoplasty decompresses the nerve roots by osteoplastic enlargement of the lumbar spinal canal, with the maintenance of spinal stability. These advantages were confirmed during the follow-up of 3 to 5 years. Using CT, the spinal canal was found to be enlarged to a nearly rectangular shape and the average enlargement was 124%. The visual analogue scale (VAS) was used for subjective pain assessment before and after the surgery. The ultimate outcome was assessed by the Surin et al. criteria (Spine 17:1-8, 1992).     

Which factors prognosticate rotational instability following lumbar laminectomy?

Purpose

Reduced strength and stiffness of lumbar spinal motion segments following laminectomy may lead to instability. Factors that predict shear biomechanical properties of the lumbar spine were previously published. The purpose of the present study was to predict spinal torsion biomechanical properties with and without laminectomy from a total of 21 imaging parameters.

Method

Radiographs and MRI of ten human cadaveric lumbar spines (mean age 75.5, range 59–88 years) were obtained to quantify geometry and degeneration of the motion segments. Additionally, dual X-ray absorptiometry (DXA) scans were performed to measure bone mineral content and density. Facet-sparing lumbar laminectomy was performed either on L2 or L4. Spinal motion segments were dissected (L2–L3 and L4–L5) and tested in torsion, under 1,600 N axial compression. Torsion moment to failure (TMF), early torsion stiffness (ETS, at 20–40 % TMF) and late torsion stiffness (LTS, at 60–80 % TMF) were determined and bivariate correlations with all parameters were established. For dichotomized parameters, independent-sample t tests were used.

Results

Univariate analyses showed that a range of geometric characteristics and disc and bone quality parameters were associated with torsion biomechanical properties of lumbar segments. Multivariate models showed that ETS, LTS and TMF could be predicted for segments without laminectomy (r ² values 0.693, 0.610 and 0.452, respectively) and with laminectomy (r ² values 0.952, 0.871 and 0.932, respectively), with DXA-derived measures of bone quality and quantity as the main predictors.

Conclusions

Vertebral bone content and geometry, i.e. intervertebral disc width, frontal area and facet joint tropism, were found to be strong predictors of ETS, LTS and TMF following laminectomy, suggesting that these variables could predict the possible development of post-operative rotational instability following lumbar laminectomy. Proposed diagnostic parameters might aid surgical decision-making when deciding upon the use of instrumentation techniques.