Segmental Lumbar Lordosis Research Articles

Effect of Single-Level Transforaminal Lumbar Interbody Fusion on Segmental and Overall Lumbar Lordosis in Patients with Lumbar Degenerative Disease.

To investigate the ability of transforaminal lumbar interbody fusion (TLIF) to improve lumbar lordosis (LL). In this retrospective study, 92 patients undergoing single-level TLIF to treat lumbar degenerative disease were divided into a low back pain, radiculopathy, and neurogenic claudication group according to their symptoms. Preoperative and postoperative measures, including segmental LL, whole LL, pelvic incidence (PI), pelvic tilt, thoracic kyphosis, sagittal vertical axis, visual analog scale for back and leg pain, and Oswestry Disability Index, were used to evaluate radiographic and clinical outcomes. All clinical parameters were significantly improved after TLIF. There was no significant difference in any radiographic parameters in the low back pain group. In the radiculopathy and neurogenic claudication groups, all radiographic parameters were significantly changed after TLIF except for segmental LL and PI in both groups and pelvic tilt in the radiculopathy group. No statistically significant differences were found in improvement of segmental LL, PI, thoracic kyphosis, and visual analog scale (leg) between the radiculopathy and neurogenic claudication groups, whereas the differences in improvement of whole LL, pelvic tilt, PI-LL, sagittal vertical axis, visual analog scale (back), and Oswestry Disability Index were significant between the 2 groups. For patients with neurogenic leg symptoms owing to single-level lumbar degenerative disease, whole LL was improved after TLIF as a result of spontaneous restoration of lordosis at the unfused lumbar levels.

Motion preservation following total lumbar disc replacement at the lumbosacral junction: a prospective long-term clinical and radiographic investigation

Background ContextTotal lumbar disc replacement (TDR) intends to avoid fusion-related negative side effects by means of motion preservation. Despite their widespread use, the adequate quality and quantity of motion, as well as the correlation between radiographic data with the patient's clinical symptomatology, remains to be established. Long-term data are lacking in particular. PurposeThis study aimed to perform a clinical and radiographic long-term investigation following TDR with special emphasis on motion preservation assessment and to establish any potential correlation with patient-reported outcome parameters. Study Design/SettingA prospective, single-center, clinical, and radiological investigation following TDR with ProDisc II (Synthes, Paoli, PA, USA) was carried out. Patient SamplePatients with a minimum 5-year follow-up (FU) after TDR performed for the treatment of intractable and predominant (≥80%) axial low back pain resulting from single-level degenerative disc disease without instabilities or deformities at the lumbosacral junction (L5–S1) comprised the sample. Outcome MeasuresVisual analogue scale (VAS), Oswestry Disability Index (ODI), and patient satisfaction rates (three-scale outcome rating), range of motion (ROM) at the index- and cranially adjacent level as well as segmental lumbar lordosis (SLL) and global lumbar lordosis (GLL) were the outcome measures. MethodsAll data were acquired within the framework of an ongoing prospective clinical trial. Patients were examined preoperatively, 3, 6, and 12 months postoperatively, and annually thereafter. X-rays were performed in antero-posterior and lateral views as well as functional flexion/extension images. Radiological examinations included ROM at the index and cranially adjacent level as well as SLL and GLL. X-ray measurements were correlated with the clinical outcome parameters. A longitudinal analysis was performed between baseline data with those from the early (3–6 months), mid- (12–24 months), and late FU stages (≥5 years). ResultsResults from 51 patients with a mean FU of 7.8 years (range 5.0–13.3 years) were available for the final analysis. X-ray measurements revealed a maintained mobility with a trend toward gradually declining ROM values. Although no statistically significant difference in ROM was detected between the preoperative and early FU (6.8° vs. 5.8°, p=.1), a further reduction in ROM became statistically significant at the mid- and final FU, with mean ROM of 5.2° and 4.4°, respectively (p<.001).Global lumbar lordosis increased from 48.8° to 54.4° (p<.0001) which was attributed to a lordotic shift from 18.2° to 28.0° at the index segment (p<.00001) and which was positively correlated with the applied implant lordosis (p<.05). A compensatory reduction of lordosis was observed at the cranially adjacent segment (p<.0001). The mobility of the cranially adjacent level remained unchanged (p>.05).The clinical outcome scores (VAS, ODI) revealed a significant improvement from baseline levels (p<.05). The reduction in ROM was not negatively correlated with the patient's clinical symptomatology (p>.05). ConclusionThe present data reveal an increased GLL resulting from a lordotic shift of the index segment, which was strongly correlated with the applied implant lordosis. This lordotic shift was accompanied by a compensatory reduction of lordosis at the cranially adjacent segment.A gradual and statistically significant decline of the device mobility was noted over time which, however, did not negatively impact the patient's clinical symptomatology.Although the present long-term investigation provides additional insight into longitudinal radiographic changes and their influence on the patient's clinical symptomatology following TDR, the adequate quality and quantity of motion with artificial motion-preserving implants remains to be established, which will aid in defining more refined treatment concepts for both fusion and motion preserving techniques alike.

MULTICENTER ANALYSIS OF THE RESULTS OF APPLICATION OF DIRECT LATERAL INTERBODY FUSION (DLIF) AND TRANSCUTANEOUS TRANSPEDICULAR FIXATION IN PATIENTS WITH DEGENERATIVE DISC DISEASES OF THE LUMBAR SPINE

Background: The technique of lateral lumbar interbody fusion for the surgical treatment of patients with degenerative diseases of the lumbar spine was developed in the early 2000s. But at the same time in modern literature there is no uniform approach to the use this technique, clinical outcomes and radiological findings are contradictory. Aims: to conduct a multicenter analysis of clinical outcomes and instrumental data of direct lateral interbody fusion (DLIF) approach combined with transcutaneous pedicle fixation in patients with single-level degenerative disc diseases of the lumbar spine. Materials and methods: The study included 103 patients (63 men and 40 women, mean age 45.8±9.7 years) who underwent surgery followed by DLIF transcutaneous pedicle fixation. The surgery was performed at neurosurgical and vertebrological departments in Irkutsk (Russia), Omsk (Russia), and Astana (Kazakhstan). Dynamic observation and comprehensive clinical and instrumental evaluation of the treatment results were carried out for an 18-month period after surgery. Results: After the simultaneous decompressive-stabilizing intervention, in all patients we detected a decrease in the severity of pain syndrome on VAS — from 6.9±1.6 to 1.7±1.2 cm (p0.001), and improved quality of life index (Oswestry) — from 21.3±6.8 to 12.3±4.4% (p0.001). The instrumental methods of examination determined the effective indirect decompression: an increase in the size of interbody gap in the middle of its department compared with the preoperative value from 8.6±3.1 to 15.7±4.2 mm (p0.001) and an increase in the area of the intervertebral foramen (on the left with an average of 98.7±32.3 and 156.8±45.1 mm2, p0.001; on the right —99.7±37.3 to 153.4±38.7 mm2, p0.001). We also registered the restoration of both the segmental (from 10.2±3.8 to 13.6±6.7°, p0.001) and regional (from 32.8±5.9 to 48.2±7.3°, р0.001) lumbar lordosis. Complete interbody fusion was diagnosed in 87 (86.4%) patients. Complications were observed in 8.7% of cases. Conclusions: DLIF technique combined with transcutaneous transpedicular stabilization has high clinical efficacy confirmed by significant reduction in the severity of pain according to VAS. The studied approach improves the quality of life of patients by Oswestry index and reveals a low number of postoperative complications. The described simultaneous minimally invasive method of surgical treatment in patients with degenerative disc diseases allows to restore the sagittal profile of the lumbar spine and implement an effective stabilization of the operated vertebral-motor segments with a high degree of formation of interbody bone block.

Two Years Experiences with a New Titanium-Coated Radiolucent TLIF Carbon-PEEK Cage

Introduction PLIF and TLIF are standard treatment methods for many degenerative spinal diseases that result in spinal stenosis or segmental instability. The cage-bone surface has a role in facilitating osteointegration. A significant quality and quantity increase of bone on growth was achieved with the titanium (Ti) coating by vacuum plasma spraying (VPS). This study aimed to evaluate the short-term radiological and clinical results of the carbon fiber-reinforced PEEK (carbon/PEEK) interbody fusion cage, coated with VPS-Ti. Patients and Methods A total of 42 Patients (47 levels), mean age 59.6, receiving cage treatment were scanned retrospectively. Pre-, postoperative, and final follow-up graphs, and clinical information were obtained. Primary diagnoses were degenerative spinal diseases. Pedicle screws were used in all cases. TLIF and PLIF technique was applied in 28 and 72% of patients. Around 51% were L4–5, 23% L5–S1, 17% L3–4, and 9% L2–3. Local graft was used in 39 patients, DBM in 2 patients, and BCT in 1 patient. The following were measured/evaluated: (1) Segmental lumbar lordosis; (2) Radiological fusion according to the IBF grading system of Bridwell; (3) Early degeneration in neighboring disks; (4) Foraminal and segmental height and loss of disc height using the Mochida index; (5) Pedicle screws' loosening. Results A mean change of 1.38 degrees was observed in the angle of neighboring segment lordosis, and an increase of 0.59 degrees was obtained in the global lumbar lordosis. Grade 1 fusion (according to the four-point Bridwell classification) was achieved in 94% of all patients 18 months after the operation (6% grade 2, 0% grades 3 and 4). Two (4.3%) patients underwent operation due to neighboring segment degeneration during the follow-up period. Progression of degeneration in the neighboring segment discs increased by 10.95% between preoperative and final follow-up graphs. In two patients, a pedicle screw loosening angle of 2 degrees and/or above was observed, no reintervention was needed. In the final follow-up at 24 months, the segmental height and foraminal height Mochida index were 5.8 and 3.82, as compared with the early postoperative graph. Around 87% of the patients had good or perfect results. Discussion Solid fusion was achieved in all but one patient after 2 years, the complication rate was low. Limitations of the study include its predominantly radiological structure, the lack of control group, and the relatively short follow-up of 2 years that may explain the relatively low number of patients who underwent a secondary operation due to neighboring segment degeneration. PEEK and carbon/PEEK increases the formation of surrounding fibrous tissue because of the hydrophobic surface structure. Therefore, carbon/PEEK was coated with VPS Ti, facilitating osteointegration while remaining its radiolucent properties. The first VPS Ti-coated cage proved to be clinically successful and is commonly accepted as a suitable geometrical shape. These findings must be supported with long-term results.

Transforaminal Lumbar Interbody Graft Placement Using an Articulating Delivery Arm Facilitates Increased Segmental Lordosis With Superior Anterior and Midline Graft Placement

Transforaminal lumbar interbody fusion (TLIF) is a frequently performed method of lumbar arthrodesis in patients failing medical management of back and leg pain. Accurate placement of the interbody graft and restoration of lordosis has been shown to be crucial when performing lumbar fusion procedures. We performed a single-surgeon, prospective, randomized study to determine whether a novel articulating versus traditional straight graft delivery arm system allows for superior graft placement and increased lordosis for single-level TLIF. Thirty consecutive patients undergoing single-level TLIF were included and prospectively randomized to one of the 2 groups (articulated vs. straight delivery arm system). Three radiographic characteristics were evaluated at 6-week follow-up: (1) degree of segmental lumbar lordosis at the fused level; (2) the percent anterior location of the interbody graft in disk space; and (3) the distance (mm) off midline of the interbody graft placement. Randomization yielded 16 patients in the articulated delivery arm cohort and 14 in the straight delivery arm cohort. The articulating delivery arm system yielded an average of 14.7-degree segmental lordosis at fused level, 35% anterior location, and 3.6 mm off midline. The straight delivery arm system yielded an average of 10.7-degree segmental lordosis at fused level, 46% anterior location, and 7.0 mm off midline. All 3 comparisons were statistically significant (P<0.05). The study suggests that an articulating delivery arm system facilitates superior anterior and midline TLIF graft placement allowing for increased segmental lordosis compared with a traditional straight delivery arm system.

Finite element analysis of lordosis restoration with anterior longitudinal ligament release and lateral hyperlordotic cage placement.

Restoring sagittal alignment is an important factor in the treatment of spinal deformities. Recent investigations have determined that releasing the anterior longitudinal ligament (ALL) and placing hyperlordotic cages can increase lordosis, while minimizing need for 3 column osteotomies. The influences of parameters such as cage height and angle have not been determined. Finite element analysis was employed to assess the extent of lordosis achievable after placement of different sized lordotic cages. A 3-dimensional model of a L3-4 segment was used. Disc distraction was simulated by inserting interbody cages mid-body in the disc space. Analyses were performed in the following conditions: (1) intact, (2) ALL release, (3) ALL release + facetectomy, and (4) ALL release + posterior column osteotomy. Changes in segmental lordosis, disc height, foraminal height, and foraminal area were measured. After ALL resection and insertion of hyperlordotic cages, lordosis was increased in all cases. The lordosis achieved by the shorter cages was less due to posterior disc height maintained by the facet joints. A facetectomy increased segmental lordosis, but led to contact between the spinous processes. For some configurations, a posterior column osteotomy was required if the end goal was to match cage angle to intradiscal angle. Increased segmental lumbar lordosis is achievable with hyperlordotic cages after ALL resection. Increased cage height tended to increase the amount of lordosis achieved, although in some cases additional posterior bone resection was required to maximize lordosis. Further studies are needed to evaluate the impact on regional lumbar lordosis.

The relationship between the spinopelvic balance and the incidence of adjacent vertebral fractures following percutaneous vertebroplasty.

We evaluated the relationship between sagittal spinopelvic parameters and the occurrence of adjacent vertebral fractures (AVF) and determined the possible risk factor. The most important factors for AVFs are the degree of osteoporosis and altered biomechanics due to the spinopelvic imbalance in the fractured area of the spine. We intend to evaluate the relationship between sagittal spinopelvic parameters and the occurrence of adjacent vertebral fractures following the initial compression fracture and to determine the possible dominant risk factor associated with new compression fractures. From March 2010 to May 2012, 240 consecutive patients with painful vertebral compression fractures (VCFs) were enrolled in a retrospective study. Ninety-one patients with VCFs underwent percutaneous vertebroplasty (VP) at 112 levels. The sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), and segmental kyphotic angle on sagittal standing radiographs were used to evaluate radiologic outcomes. In 2 years, 15 out of 134 patients (11.1%) treated with conservative treatment, and 12 out of 91 patients (13.1%) treated with VP sustained adjacent level fracture. More patients with the BMD higher or equal to 3.0 experienced a new fracture than those with a BMD less than 3.0 (p = 0.019), and the risk for adjacent level fractures decreased significantly when segmental kyphotic angle was less than 11° (p = 0.001), SVA was less than 6 cm (p = 0.001), SS was higher or equal to 25° (p = 0.004), and LL was higher or equal to 25° (p = 0.020). The most important factors for new VCFs after the initial compression fractures are the degree of osteoporosis and altered biomechanics due to the spinopelvic imbalance in the fractured area of the spine. Regarding the spinopelvic alignment to investigate the relationship with a subsequent AVF, segmental kyphotic angle, SS, LL, and SVA may be a potential predictor.

A Comparative Study of Lateral Lumbar Interbody Fusion and Posterior Lumbar Interbody Fusion in Degenerative Lumbar Spondylolisthesis.

Study DesignLevel 4 retrospective review.PurposeTo compare the radiographic and clinical outcomes between posterior lumbar interbody fusion (PLIF) and lateral lumbar interbody fusion (LLIF) with posterior segmental spinal instrumentation (SSI) for degenerative lumbar spondylolisthesis.Overview of LiteratureBoth PLIF and LLIF have been performed for degenerative spondylolisthesis with good results, but no study has directly compared these two techniques so far.MethodsThe electronic medical and radiographic records of 78 matched patients were analyzed. In one group, 39 patients underwent PLIF with SSI at 41 levels (L3-4/L4-5), while in the other group, 39 patients underwent the LLIF procedure at 48 levels (L3-4/L4-5). Radiological outcomes such as restoration of disc height and neuroforaminal height, segmental lumbar lordosis, total lumbar lordosis, incidence of endplate fracture, and subsidence were measured. Perioperative parameters were also recorded in each group. Clinical outcome in both groups was assessed by the short form-12, Oswestry disability index and visual analogue scale scores. The average follow-up period was 16.1 months in the LLIF group and 21 months in the PLIF group.ResultsThe restoration of disc height, foraminal height, and segmental lumbar lordosis was significantly better in the LLIF group (p<0.001). The duration of the operation was similar in both groups, but the average blood loss was significantly lower in the LLIF group (p<0.001). However, clinical outcome scores were similar in both groups.ConclusionsSafe, effective interbody fusion can be achieved at multiple levels with neuromonitoring by the lateral approach. LLIF is a viable treatment option in patients with new onset symptoms due to degenerative spondylolisthesis who have had previous lumbar spine surgery, and it results in improved sagittal alignment and indirect foraminal decompression.

Effects of lordotic angle of a cage on sagittal alignment and clinical outcome in one level posterior lumbar interbody fusion with pedicle screw fixation.

This study aims to assess the differences in the radiological and clinical results depending on the lordotic angles of the cage in posterior lumbar interbody fusion (PLIF). We reviewed 185 segments which underwent PLIF using two different lordotic angles of 4° and 8° of a polyetheretherketone (PEEK) cage. The segmental lordosis and total lumbar lordosis of the 4° and 8° cage groups were compared preoperatively, as well as on the first postoperative day, 6th and 12th months postoperatively. Clinical assessment was performed using the ODI and the VAS of low back pain. The pre- and immediate postoperative segmental lordosis angles were 12.9° and 12.6° in the 4° group and 12° and 12.0° in the 8° group. Both groups exhibited no significant different segmental lordosis angle and total lumbar lordosis over period and time. However, the total lumbar lordosis significantly increased from six months postoperatively compared with the immediate postoperative day in the 8° group. The ODI and the VAS in both groups had no differences. Cages with different lordotic angles of 4° and 8° showed insignificant results clinically and radiologically in short-level PLIF surgery. Clinical improvements and sagittal alignment recovery were significantly observed in both groups.

Surgical treatment of degenerative lumbar kyphosis (literature review)

An analytical review of scientific information on surgical treatment of degenerative lumbar kyphosis have been represented. It outlines the main stages of history of development of a trend in vertebrology which is associated with correction of kyphotic deformity of the lumbar spine as well as with evolution of the spinal implants and surgical approaches to treatment of patients with this pathology. Information on normal values of segmental and total lumbar lordosis as well as on common surgical procedures for correction of lumbar kyphosis have been represented. Correlation between the lumbar-pelvic balance and sagittal lumbar contour was revealed. Perspectives of scientific research in this direction were targeted.

Management of sagittal balance in adult spinal deformity with minimally invasive anterolateral lumbar interbody fusion: a preliminary radiographic study

Minimally invasive (MI) fusion and instrumentation techniques are playing a new role in the treatment of adult spinal deformity. The open pedicle subtraction osteotomy (PSO) and Smith-Petersen osteotomy (SPO) are proven segmental methods for improving regional lordosis and global sagittal parameters. Recently the MI anterior column release (ACR) was introduced as a segmental method for treating sagittal imbalance. There is a paucity of data in the literature evaluating the alternatives to PSO and SPO for sagittal balance correction. Thus, the authors conducted a preliminary retrospective radiographic review of prospectively collected data from 2009 to 2012 at a single institution. The objectives of this study were to: 1) investigate the radiographic effect of MI-ACR on spinopelvic parameters, 2) compare the radiographic effect of MI-ACR with PSO and SPO for treatment of adult spinal deformity, and 3) investigate the radiographic effect of percutaneous posterior spinal instrumentation on spinopelvic parameters when combined with MI transpsoas lateral interbody fusion (LIF) for adult spinal deformity. Patient demographics and radiographic data were collected for 36 patients (9 patients who underwent MI-ACR and 27 patients who did not undergo MI-ACR). Patients included in the study were those who had undergone at least a 2-level MI-LIF procedure; adequate preoperative and postoperative 36-inch radiographs of the scoliotic curvature; a separate second-stage procedure for the placement of posterior spinal instrumentation; and a diagnosis of degenerative scoliosis (coronal Cobb angle > 10° and/or sagittal vertebral axis > 5 cm). Statistical analysis was performed for normality and significance testing. Percutaneous transpedicular spinal instrumentation did not significantly alter any of the spinopelvic parameters in either the ACR group or the non-ACR group. Lateral MI-LIF alone significantly improved coronal Cobb angle by 16°, and the fractional curve significantly improved in a subgroup treated with L5-S1 transforaminal lumbar interbody fusion. Fifteen ACRs were performed in 9 patients and resulted in significant coronal Cobb angle correction, lumbar lordosis correction of 16.5°, and sagittal vertebral axis correction of 4.8 cm per patient. Segmental analysis revealed a 12° gain in segmental lumbar lordosis and a 3.1-cm correction of the sagittal vertebral axis per ACR level treated. The lateral MI-LIF with ACR has the ability to powerfully restore lumbar lordosis and correct sagittal imbalance. This segmental MI surgical technique boasts equivalence to SPO correction of these global radiographic parameters while simultaneously creating additional disc height and correcting coronal imbalance. Addition of posterior percutaneous instrumentation without in situ manipulation or overcorrection does not alter radiographic parameters when combined with the lateral MI-LIF.

Comparison of Sagittal Spinopelvic Alignment between Lumbar Degenerative Spondylolisthesis and Degenerative Spinal Stenosis.

ObjectiveThe purpose of this study was to evaluate the differences in sagittal spinopelvic alignment between lumbar degenerative spondylolisthesis (DSPL) and degenerative spinal stenosis (DSS).MethodsSeventy patients with DSPL and 72 patients with DSS who were treated with lumbar interbody fusion surgery were included in this study. The following spinopelvic parameters were measured on whole spine lateral radiographs in a standing position : pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis angle (LL), L4-S1 segmental lumbar angle (SLL), thoracic kyphosis (TK), and sagittal vertical axis from the C7 plumb line (SVA). Two groups were subdivided by SVA value, respectively. Normal SVA subgroup and positive SVA subgroup were divided as SVA value (<50 mm and ≥50 mm). Spinopelvic parameters/PI ratios were assessed and compared between the groups.ResultsThe PI of DSPL was significantly greater than that of DSS (p=0.000). The SVA of DSPL was significantly greater than that of DSS (p=0.001). In sub-group analysis between the positive (34.3%) and normal SVA (65.7%), there were significant differences in LL/PI and SLL/PI (p<0.05) in the DSPL group. In sub-group analysis between the positive (12.5%) and normal SVA (87.5%), there were significant differences in PT/PI, SS/PI, LL/PI and SLL/PI ratios (p<0.05) in the DSS group.ConclusionPatients with lumbar degenerative spondylolisthesis have the propensity for sagittal imbalance and higher pelvic incidence compared with those with degenerative spinal stenosis. Sagittal imbalance in patients with DSPL is significantly correlated with the loss of lumbar lordosis, especially loss of segmental lumbar lordosis.

Radiographic and clinical evaluation of cage subsidence after stand-alone lateral interbody fusion

Indirect decompression of the neural structures through interbody distraction and fusion in the lumbar spine is feasible, but cage subsidence may limit maintenance of the initial decompression. The influence of interbody cage size on subsidence and symptoms in minimally invasive lateral interbody fusion is heretofore unreported. The authors report the rate of cage subsidence after lateral interbody fusion, examine the clinical effects, and present a subsidence classification scale. The study was performed as an institutional review board-approved prospective, nonrandomized, comparative, single-center radiographic and clinical evaluation. Stand-alone short-segment (1- or 2-level) lateral lumbar interbody fusion was investigated with 12 months of postoperative follow-up. Two groups were compared. Forty-six patients underwent treatment at 61 lumbar levels with standard interbody cages (18 mm anterior/posterior dimension), and 28 patients underwent treatment at 37 lumbar levels with wide cages (22 mm). Standing lateral radiographs were used to measure segmental lumbar lordosis, disc height, and rate of subsidence. Subsidence was classified using the following scale: Grade 0, 0%-24% loss of postoperative disc height; Grade I, 25%-49%; Grade II, 50%-74%; and Grade III, 75%-100%. Fusion status was assessed on CT scanning, and pain and disability were assessed using the visual analog scale and Oswestry Disability Index. Complications and reoperations were recorded. Pain and disability improved similarly in both groups. While significant gains in segmental lumbar lordosis and disc height were observed overall, the standard group experienced less improvement due to the higher rate of interbody graft subsidence. A difference in the rate of subsidence between the groups was evident at 6 weeks (p = 0.027), 3 months (p = 0.042), and 12 months (p = 0.047). At 12 months, 70% in the standard group and 89% in the wide group had Grade 0 or I subsidence, and 30% in the standard group and 11% in wide group had Grade II or III subsidence. Subsidence was detected early (6 weeks), at which point it was correlated with transient clinical worsening, although progression of subsidence was not observed after the 6-week time point. Moreover, subsidence occurred predominantly (68%) in the inferior endplate. Fusion rate was not affected by cage dimension (p > 0.999) or by incidence of subsidence (p = 0.383). Wider cages avoid subsidence and better restore segmental lordosis in stand-alone lateral interbody fusion. Cage subsidence is identified early in follow-up and can be accessed using the proposed classification scale.

Posterior inter-body fusion in lumbar spine surgery: A systematic review

Abstract Background Posterolateral fusion (PLF) is a common method for achieving fusion in lumbar spine surgery. Posterior lumbar inter-body fusion (PLIF) has been reported to give a higher fusion rate and a better functional and clinical outcome. Objectives The objective of the review was to determine whether PLIF is more effective than PLF in improving clinical and radiological outcomes in adults surgically treated for degenerative lumbar spine conditions. Methods Electronic databases, bibliographies and relevant journals were searched systematically, and a meta-analysis was conducted. Results Of 2798 citations identified, five studies met our inclusion criteria; none was a randomized controlled trial. A total of 148 patients had undergone PLIF (intervention) and 159 PLF (control). Pooled meta-analyses showed that non-union rates were lower in the intervention group (relative risk (RR), 0.22; 95% confidence interval (CI), 0.08–0.62). The intervention group had significantly heavier disc height (weighted mean difference, 3.2 mm; 95% CI, 1.9–4.4) and less residual percentage slippage (weighted mean difference, 6.3%; 95% CI, 3.9–8.7) at final follow-up. No significant difference in segmental or total lumbar lordosis was seen. Because of the heterogeneity of the results, no conclusion could be drawn about the functional benefits of the two procedures. Conclusion This review suggests that PLIF results in a higher fusion rate and better correction of certain radiographic aspects of deformity than PLF. It also showed a slight but nonsignificant trend towards a better functional outcome with PLIF. The lack of randomized controlled trials and the methodological limitations of the available studies indicate the need for a sufficiently large, methodologically sound study with clinically relevant outcome measures. Until this has been done, the evidence for the beneficial effects of posterior inter-body fusion should be interpreted with caution.

Pelvic parameters of sagittal balance in extreme lateral interbody fusion for degenerative lumbar disc disease

There is increasing interest in the use of pelvic indices to evaluate sagittal balance and predict outcomes in patients with spinal disease. Conventional posterior lumbar fusion techniques may adversely affect lumbar lordosis and spinal balance. Minimally invasive fusion of the lumbar spine is rapidly becoming a mainstay of treatment of lumbar degenerative disc disease. To our knowledge there are no studies evaluating the effect of extreme lateral interbody fusion (XLIF) on pelvic indices. Hence, our aim was to study the effect of XLIF on pelvic indices related to sagittal balance, and report the results of a prospective longitudinal clinical study and retrospective radiographic analyses of patients undergoing XLIF in a single centre between January 2009 and July 2011. Clinical outcomes are reported for 30 patients and the retrospective analyses of radiographic data is reported for 22 of these patients to assess global and segmental lumbar lordosis and pelvic indices. Effect of XLIF on the correction of scoliotic deformity was assessed in 15 patients in this series. A significant improvement was seen in the visual analogue scale score, the Oswestry Disability Index and the Short Form-36 at 2months and 6months (p<0.0001). The mean pelvic index was 48.6°±11.9° (± standard deviation, SD) with corresponding mean sacral slopes and pelvic tilt of 32.0°±10.6° (SD) and 18.0°±9.5 (SD), respectively. XLIF did not significantly affect sacral slope or pelvic tilt (p>0.2). Global lumbar lordosis was not affected by XLIF (p>0.4). XLIF significantly increased segmental lumbar lordosis by 3.3° (p<0.0001) and significantly decreased the scoliotic Cobb angle by 5.9° (p=0.01). We found that XLIF improved scoliosis and segmental lordosis and was associated with significant clinical improvement in patients with lumbar degenerative disc disease. However, XLIF did not change overall lumbar lordosis or significantly alter pelvic indices associated with sagittal balance. Long-term follow-up with a larger cohort will be required to further evaluate the effects of XLIF on sagittal balance.

Effect of Total Lumbar Disc Replacement on Lumbosacral Lordosis

Original article : To study effect of lumbar disc replacement on lumbosacral lordosis. There has been a growing interest in total disc replacement (TDR) for back pain with the rising concern of adjacent segment degeneration. Lumbar fusion surgery has been shown to lead to decrease in lumbar lordosis, which may account for postfusion pain resulting in less acceptable clinical outcome after successful fusion. TDR has recently emerged as an alternative treatment for back pain. There have been very few studies reporting lumbar sagittal outcome after TDR. Retrospective study of radiographic data of 17 patients who underwent TDR for single level degenerative disc disease at the author's institution was carried out. Study included measurement of preoperative and postoperative segmental and global lumbar lordosis and angle of lordosis. Patients age varied from 19 to 54 (mean, 35) years. Follow-up ranged from 12 to 24 months. TDR was performed at L4-5 level in 3 patients and L5-S1 level in 14 patients. The average values for segmental lordosis, global lordosis, and angle of lordosis at the operated level before and after surgery were 17.3, 49.7, and 8.6 degrees and 21.6, 54, and 9.5 degrees, respectively. There was a trend toward significant (P=0.02) and near significant (P=0.057) increase in segmental and global lordosis, respectively after TDR. Although prosthesis increased angle of lordosis at the level implanted in majority of the patients, the difference in preoperative and postoperative angle of lordosis was not significant (P=0.438). In addition, there was no correlation between the angle of implant of chosen and postoperative angle of lordosis at the operated level. The effect of TDR on sagittal balance appears favorable with an increase in global and segmental lumbar lordosis after single level TDR for degenerative disc disease. The degree of postoperative angle of lordosis was not affected by the angle of implant chosen at the operated level and varied independently of the implant angle.

Anterior longitudinal ligament release using the minimally invasive lateral retroperitoneal transpsoas approach: a cadaveric feasibility study and report of 4 clinical cases

Traditional procedures for correction of sagittal imbalance via shortening of the posterior column include the Smith-Petersen osteotomy, pedicle subtraction osteotomy, and vertebral column resection. These procedures require wide exposure of the spinal column posteriorly, and may be associated with significant morbidity. Anterior longitudinal ligament (ALL) release using the minimally invasive lateral retroperitoneal approach with a resultant net lengthening of the anterior column has been performed as an alternative to increase lordosis. The objective of this study was to demonstrate the feasibility and early clinical experience of ALL release through a minimally invasive lateral retroperitoneal transpsoas approach, as well as to describe its surgical anatomy in the lumbar spine. Forty-eight lumbar levels were dissected in 12 fresh-frozen cadaveric specimens to study the anatomy of the ALL as well as its surrounding structures, and to determine the feasibility of the technique. The lumbar disc spaces and ALL were accessed via the lateral transpsoas approach and confirmed with fluoroscopy in each specimen. As an adjunct, 4 clinical cases of ALL release through the minimally invasive lateral retroperitoneal transpsoas approach were reviewed. Operative technique, results, complications, and early outcomes were assessed. In the cadaveric study, sectioning of the ALL proved to be feasible from the minimally invasive lateral retroperitoneal transpsoas approach. The structures at most immediate risk during this procedure were the aorta, inferior vena cava, iliac vessels, and sympathetic plexus. The mean increase in segmental lumbar lordosis per level of ALL release was 10.2°, while global lumbar lordosis improved by 25°. Each level of ALL release took 56 minutes and produced 40 ml of blood loss on average. Visual analog scale and Oswestry Disability Index scores improved by 9 and 35 points, respectively. There were no cases of hardware failure, and as of yet no complications to report. This initial experience suggests that ALL release through the minimally invasive lateral retroperitoneal transpsoas approach may be feasible, allows for improvement of lumbar lordosis without the need of an open laparotomy/thoracotomy, and minimizes the tissue disruption and morbidity associated with posterior osteotomies.

Lordosis restoration after anterior longitudinal ligament release and placement of lateral hyperlordotic interbody cages during the minimally invasive lateral transpsoas approach: a radiographic study in cadavers

In the surgical treatment of spinal deformities, the importance of restoring lumbar lordosis is well recognized. Smith-Petersen osteotomies (SPOs) yield approximately 10° of lordosis per level, whereas pedicle subtraction osteotomies result in as much as 30° increased lumbar lordosis. Recently, selective release of the anterior longitudinal ligament (ALL) and placement of lordotic interbody grafts using the minimally invasive lateral retroperitoneal transpsoas approach (XLIF) has been performed as an attempt to increase lumbar lordosis while avoiding the morbidity of osteotomy. The objective of the present study was to measure the effect of the selective release of the ALL and varying degrees of lordotic implants placed using the XLIF approach on segmental lumbar lordosis in cadaveric specimens between L-1 and L-5. Nine adult fresh-frozen cadaveric specimens were placed in the lateral decubitus position. Lateral radiographs were obtained at baseline and after 4 interventions at each level as follows: 1) placement of a standard 10° lordotic cage, 2) ALL release and placement of a 10° lordotic cage, 3) ALL release and placement of a 20° lordotic cage, and 4) ALL release and placement of a 30° lordotic cage. All four cages were implanted sequentially at each interbody level between L-1 and L-5. Before and after each intervention, segmental lumbar lordosis was measured in all specimens at each interbody level between L-1 and L-5 using the Cobb method on lateral radiography. The mean baseline segmental lordotic angles at L1-2, L2-3, L3-4, and L4-5 were -3.8°, 3.8°, 7.8°, and 22.6°, respectively. The mean lumbar lordosis was 29.4°. Compared with baseline, the mean postimplantation increase in segmental lordosis in all levels combined was 0.9° in Intervention 1 (10° cage without ALL release); 4.1° in Intervention 2 (ALL release with 10° cage); 9.5° in Intervention 3 (ALL release with 20° cage); and 11.6° in Intervention 4 (ALL release with 30° cage). Foraminal height in the same sequence of conditions increased by 6.3%, 4.6%, 8.8% and 10.4%, respectively, while central disc height increased by 16.1%, 22.3%, 52.0% and 66.7%, respectively. Following ALL release and placement of lordotic cages at all 4 lumbar levels, the average global lumbar lordosis increase from preoperative lordosis was 3.2° using 10° cages, 12.0° using 20° cages, and 20.3° using 30° cages. Global lumbar lordosis with the cages at 4 levels exhibited a negative correlation with preoperative global lordosis (10°, R = -0.756; 20°, -0.730; and 30°, R = -0.437). Combined ALL release and placement of increasingly lordotic lateral interbody cages leads to progressive gains in segmental lordosis in the lumbar spine. Mean global lumbar lordosis similarly increased with increasingly lordotic cages, although the effect with a single cage could not be evaluated. Greater global lordosis was achieved with smaller preoperative lordosis. The mean maximum increase in segmental lordosis of 11.6° followed ALL release and placement of the 30° cage.

Factors Affecting Clinical Outcomes in Treating Patients With Grade 1 Degenerative Spondylolisthesis Using Interspinous Soft Stabilization With a Tension Band System

Retrospective clinical study. To explore the factors influencing the clinical outcomes and motion-preserving stabilization after interspinous soft stabilization (ISS) with a tension band system for grade 1 degenerative spondylolisthesis (DS). Despite increasing recognition of the benefits of dynamic stabilization systems for treating lumbar degenerative disorders, the factors affecting the clinical and radiological outcomes of these systems have rarely been identified. Sixty-five patients (mean age, 60.3 years) who underwent ISS with a tension band system between 2002 and 2004 were analyzed. The mean follow-up period was 72.5 months. The patients were divided according to the postsurgical clinical improvements into the optimal (n = 44) and suboptimal groups (n = 21), and the radiological intergroup differences were analyzed. Multiple linear regression analysis was performed to determine the impact of the radiological factors on the clinical outcomes. Significant intergroup differences were observed on the follow-up clinical examination. Radiologically, total lumbar lordosis (TLL) and segmental lumbar lordosis (SLL) were significantly improved only in the optimal group, resulting in significant intergroup differences in TLL (P = 0.023), SLL (P = 0.001), and the L1 tilt (P = 0.002). All these measures were closely associated with postoperative segmental lumbar lordosis, which also was the most influential radiological variable for the clinical parameters. In the patients with grade 1 DS, the back pain relief and functional improvement following ISS were affected by the improvements in the sagittal spinal alignment through the achievement of segmental lumbar lordosis. ISS can be an alternative treatment to fusion surgery for grade 1 DS in patients who do not require fixation or reduction.

Early Outcomes of Minimally Invasive Anterior Longitudinal Ligament Release for Correction of Sagittal Imbalance in Patients with Adult Spinal Deformity

The object of this study was to evaluate a novel surgical technique in the treatment of adult degenerative scoliosis and present our early experience with the minimally invasive lateral approach for anterior longitudinal ligament release to provide lumbar lordosis and examine its impact on sagittal balance. Methods. All patients with adult spinal deformity (ASD) treated with the minimally invasive lateral retroperitoneal transpsoas interbody fusion (MIS LIF) for release of the anterior longitudinal ligament were examined. Patient demographics, clinical data, spinopelvic parameters, and outcome measures were recorded. Results. Seven patients underwent release of the anterior longitudinal ligament (ALR) to improve sagittal imbalance. All cases were split into anterior and posterior stages, with mean estimated blood loss of 125 cc and 530 cc, respectively. Average hospital stay was 8.3 days, and mean follow-up time was 9.1 months. Comparing pre- and postoperative 36′′ standing X-rays, the authors discovered a mean increase in global lumbar lordosis of 24 degrees, increase in segmental lumbar lordosis of 17 degrees per level of ALL released, decrease in pelvic tilt of 7 degrees, and decrease in sagittal vertical axis of 4.9 cm. At the last followup, there was a mean improvement in VAS and ODI scores of 26.2% and 18.3%. Conclusions. In the authors' early experience, release of the anterior longitudinal ligament using the minimally invasive lateral retroperitoneal transpsoas approach may be a feasible alternative in correcting sagittal deformity.