Surgical Restoration of Sagittal Alignment of the Spine: Correlation with Improved Patient-Reported Outcomes: A Systematic Review and Meta-Analysis

BACKGROUND

The sagittal-plane curvatures of the human spine are the consequence of evolution from quadrupedalism to bipedalism and are needed to maintain the center of mass of the body within the base of support in the bipedal position. Lumbar degenerative disorders can lead to a decrease in lumbar lordosis and thereby affect overall alignment of the spine. However, there is not yet enough direct evidence that surgical restoration of spinal malalignment would lead to a better clinical outcome. Therefore, the aim of this study was to assess the correlation between patient-reported outcomes and actual obtained spinal sagittal alignment in adult patients with lumbar degenerative disorders who underwent surgical treatment.

METHODS

A comprehensive literature search was conducted through databases (PubMed, Cochrane, Web of Science, and Embase). The last search was in November 2018. Risk of bias was assessed with the Newcastle-Ottawa quality assessment scale. A meta-regression analysis was performed.

RESULTS

Of 2,024 unique articles in the original search, 34 articles with 973 patients were included. All studies were either retrospective or prospective cohort studies; no randomized controlled trials were available. A total of 54 relations between preoperative-to-postoperative improvement in patient-reported outcome measures (PROMs) and radiographic spinopelvic parameters were found, of which 20 were eligible for meta-regression analysis. Of these, 2 correlations were significant: pelvic tilt (PT) versus Oswestry Disability Index (ODI) (p = 0.009) and PT versus visual analog scale (VAS) pain (p = 0.008).

CONCLUSIONS

On the basis of the current literature, lower PT was significantly correlated with improved ODI and VAS pain in patients with sagittal malalignment caused by lumbar degenerative disorders that were treated with surgical correction of the sagittal balance.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Chordoma: a systematic review of the epidemiology and clinical prognostic factors predicting progression-free and overall survival

BACKGROUND AND AIMS

The aim of this systematic review is to describe the epidemiology of chordoma and to provide a clear overview of clinical prognostic factors predicting progression-free and overall survival.

METHODS

Four databases of medical literature were searched. Separate searches were performed for each of the two objectives. Reference and citation tracking was performed. Papers were processed by two independent reviewers according to a protocol that included risk of bias analysis. Disagreement was resolved by discussion. Pooled analyses were planned if homogeneity of data would allow.

RESULTS

Incidence-incidence rates ranged between 0.18 and 0.84 per million persons per year and varied between countries and presumably between races. On average patients were diagnosed in their late fifties and gender data indicate clear male predominance. Two of the largest studies (n = 400 and n = 544) reported different anatomical distributions: one reporting the skull base and sacrococcygeal area affected in 32% and 29% of cases, whereas the other reporting that they were affected in 26% and 45% of cases, respectively.

PROGNOSTIC FACTORS

Statistically significant adverse prognostic factors predicting progression-free and overall survival include female sex, older age, bigger tumour size, increasing extent of tumour invasion, non-total resection, presence of metastasis, local recurrence, and dedifferentiated histological subtype.

CONCLUSIONS

Incidence rate and anatomical distribution vary between countries and presumably between races. Most chordomas arise in the skull base and sacrococcygeal spine, and the tumour shows clear male predominance. Multiple adverse prognostic factors predicting progression-free and overall survival were identified in subgroups of patients. These slides can be retrieved under Electronic Supplementary Material.

Bicruciate substituting design does not improve maximal flexion in total knee arthroplasty: a randomized controlled trial

BACKGROUND

An important factor in the functional results after total knee arthroplasty is the achieved maximal flexion. The main purpose of this study was to compare the maximal knee flexion one year after surgery in patients who received either the bicruciate substituting knee system or the conventional posterior stabilized system.

METHODS

In a prospective randomized controlled trial, 124 patients presenting with osteoarthritis received the bicruciate substituting or the conventional posterior stabilized prosthesis. The primary outcome was the maximum flexion angle at one year postoperatively on a lateral radiograph made with the supine patient using manual force to bend the knee. Secondary outcomes were active flexion (lying and standing), the Knee Society Score, the Patella Scoring System score, the University of California Los Angeles score, the number and type of adverse device effects, and visual analog scale satisfaction up to two years postoperatively. The outcome measures of both groups were compared using one-sided t tests and non-parametric alternatives, with a significance level of p < 0.05.

RESULTS

No significant differences between the two groups were observed in maximal flexion on radiographs and in active flexion at baseline. The median maximal flexion on radiographs was 127° (range, 83° to 150°) for the bicruciate substituting group and 125° (range, 74° to 145°) for the conventional posterior stabilized group. The two groups showed comparable two-year results with respect to the Knee Society Score, the Patella Scoring System, the University of California Los Angeles score, and visual analog scale satisfaction. In the bicruciate substituting group, forty-one adverse device effects in twenty-six patients were reported, including three total system revisions and fourteen manipulations under anesthesia, compared with the conventional posterior stabilized group, in which sixteen adverse device effects were observed in thirteen patients, including six manipulations under anesthesia (p = 0.012).

CONCLUSIONS

Patients who receive a bicruciate substituting system compared with those who receive a conventional posterior stabilized system have comparable knee flexion characteristics and clinical and functional outcomes but more complications by two years after total knee arthroplasty.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Flexion and extension laxity after medial, mobile-bearing unicompartmental knee arthroplasty: a comparison between a spacer- and a tension-guided technique

PURPOSE

In a mobile-bearing unicompartmental knee arthroplasty (UKA), stability is of utmost importance to promote knee function and to prevent dislocation of the insert. Gap balancing can be guided by the use of spacers or a tensioner. The goal of this study is to compare laxity of a tension-guided implantation technique versus a spacer-guided technique for medial UKA with a mobile bearing. Also clinical function was compared between the groups.

METHODS

The tension-guided UKA system (BalanSys™, Mathys Ltd, Bettlach, Switzerland) was compared with a retrospective group with a spacer-guided system (Oxford, Biomet Ltd, Bridgend, UK). A total of 30 tension-guided medial UKAs were implanted and compared with 35 spacer-guided medial prostheses. In both groups, valgus laxity was measured at least 4 months postoperatively in extension and 70° flexion using stress radiographs. Knee Society Scores (KSS) were obtained at the 6-month follow-up.

RESULTS

Valgus laxity in flexion was significantly higher in the tension-guided group compared with the spacer-guided group: 3.9° (SD 1.8°) versus 2.4° (SD 1.2°), respectively, P < 0.001). In extension, valgus laxity was significantly different: 1.8° (SD 1.0°) in the tension-guided group compared with 2.7° (SD 0.9°) in the spacer-guided group (P < 0.001). There was no significant difference between the KSS for the two groups (n.s.).

CONCLUSIONS

The tensor-guided system resulted in significantly more valgus laxity in flexion compared with the spacer-guided system. However, in extension, the situation was reversed: the tension-guided system resulted in less valgus laxity than the spacer-guided system. Clinically, there were no differences between the groups. The valgus laxity found with the spacer-guided system better approximates the valgus laxity values of the healthy elderly.

A systematic review and meta-regression of mobile-bearing versus fixed-bearing total knee replacement in 41 studies

Mobile-bearing (MB) total knee replacement (TKR) was introduced to reduce the risk of aseptic loosening and wear of polyethylene inserts. However, no consistent clinical advantages of mobile- over fixed-bearing (FB) TKR have been found. In this study we evaluated whether mobile bearings have an advantage over fixed bearings with regard to revision rates and clinical outcome scores. Furthermore, we determined which modifying variables affected the outcome. A systematic search of the literature was conducted to collect clinical trials comparing MB and FB in primary TKR. The primary outcomes were revision rates for any reason, aseptic loosening and wear. Secondary outcomes included range of movement, Knee Society score (KSS), Oxford knee score (OKS), Short-Form 12 (SF-12) score and radiological parameters. Meta-regression techniques were used to explore factors modifying the observed effect. Our search yielded 1827 publications, of which 41 studies met our inclusion criteria, comprising over 6000 TKRs. Meta-analyses showed no clinically relevant differences in terms of revision rates, clinical outcome scores or patient-reported outcome measures between MB and FB TKRs. It appears that theoretical assumptions of superiority of MB over FB TKR are not borne out in clinical practice.

Systematic review of prognostic factors predicting outcome in non-surgically treated patients with sciatica

Identification of prognostic factors for surgery in patients with sciatica is important to be able to predict surgery in an early stage. Identification of prognostic factors predicting persistent pain, disability and recovery are important for better understanding of the clinical course, to inform patient and physician and support decision making. Consequently, we aimed to systematically review prognostic factors predicting outcome in non-surgically treated patients with sciatica. A search of Medline, Embase, Web of Science and Cinahl, up to March 2012 was performed for prospective cohort studies on prognostic factors for non-surgically treated sciatica. Two reviewers independently selected studies for inclusion and assessed the risk of bias. Outcomes were pain, disability, recovery and surgery. A best evidence synthesis was carried out in order to assess and summarize the data. The initial search yielded 4392 articles of which 23 articles reporting on 14 original cohorts met the inclusion criteria. High clinical, methodological and statistical heterogeneity among studies was found. Reported evidence regarding prognostic factors predicting the outcome in sciatica is limited. The majority of factors that have been evaluated, e.g., age, body mass index, smoking and sensory disturbance, showed no association with outcome. The only positive association with strong evidence was found for leg pain intensity at baseline as prognostic factor for subsequent surgery.

Recruiting patients into randomized clinical trials in surgery (Br J Surg 2012; 99: 307–308)

The Editors welcome topical correspondence from readers relating to articles published in the Journal. Responses should be sent electronically via the BJS website (http://www.bjs.co.uk). All letters will be reviewed and, if approved, appear on the website. A selection of these will be edited and published in the Journal. Letters must be no more than 250 words in length.

No effect of traction in patients with low back pain: a single centre, single blind, randomized controlled trial of Intervertebral Differential Dynamics Therapy

Low back pain (LBP) poses a significant problem to society. Although initial conservative therapy may be beneficial, persisting chronic LBP still frequently leads to expensive invasive intervention. A novel non-invasive therapy that focuses on discogenic LBP is Intervertebral Differential Dynamics Therapy (IDD Therapy, North American Medical Corp. Reg U.S.). IDD Therapy consists of intermittent traction sessions in the Accu-SPINA device (Steadfast Corporation Ltd, Essex, UK), an FDA approved, class II medical device. The intervertebral disc and facet joints are unloaded through axial distraction, positioning and relaxation cycles. The purpose of this study is to investigate the effect of IDD Therapy when added to a standard graded activity program for chronic LBP patients. In a single blind, single centre, randomized controlled trial; 60 consecutive patients were assigned to either the SHAM or the IDD Therapy. All subjects received the standard conservative therapeutic care (graded activity) and 20 sessions in the Accu-SPINA device. The traction weight in the IDD Therapy was systematically increased until 50% of a person's body weight plus 4.45 kg (10 lb) was reached. The SHAM group received a non-therapeutic traction weight of 4.45 kg in all sessions. The main outcome was assessed using a 100-mm visual analogue scale (VAS) for LBP. Secondary outcomes were VAS scores for leg pain, Oswestry Disability Index (ODI), Short-Form 36 (SF-36). All parameters were measured before and 2, 6 and 14 weeks after start of the treatment. Fear of (re)injury due to movement or activities (Tampa Scale for Kinesiophobia), coping strategies (Utrecht Coping List) and use of pain medication were recorded before and at 14 weeks. A repeated measures analysis was performed. The two groups were comparable at baseline in terms of demographic, clinical and psychological characteristics, indicating that the random allocation had succeeded. VAS low back pain improved significantly from 61 (+/-25) to 32 (+/-27) with the IDD protocol and 53 (+/-26) to 36 (+/-27) in the SHAM protocol. Moreover, leg pain, ODI and SF-36 scores improved significantly but in both groups. The use of pain medication decreased significantly, whereas scores for kinesiophobia and coping remained at the same non-pathological level. None of the parameters showed a difference between both protocols. Both treatment regimes had a significant beneficial effect on LBP, leg pain, functional status and quality of life after 14 weeks. The added axial, intermittent, mechanical traction of IDD Therapy to a standard graded activity program has been shown not to be effective.

A comparison of reproducibility of measurement techniques for patella position on axial radiographs after total knee arthroplasty

Patella position can be measured on axial radiographs and many measurement techniques have been described in literature. The goal of this study was to evaluate the inter- and intraobserver reproducibility of measurement techniques available in the literature for patients with a knee prosthesis. Fifty axial patella radiographs from knee prostheses were used to measure the reproducibility of five measurement techniques. Reproducibility was calculated using the Bland and Altman method. The Patellar Displacement (>or=4 mm) and the Lateral Patellar Tilt (>10 degrees) were found to be useful and clinically relevant. Based on our study we recommend that the most reproducible method to use for measurement of tilt, is Lateral Patellar Tilt; to measure displacement, the surgeon should use the Patellar Displacement technique.

The anterior-posterior laxity after total knee arthroplasty inserted with a ligament tensor

Goal of this study is to determine the anterior-posterior laxity in 30 degrees of knee flexion for a posterior cruciate retaining total knee arthroplasty with a relative dished insert and implanted with a ligament tensor. Furthermore, the correlation between these AP laxities and the postoperative range of motion (ROM) and postoperative Knee Society Score (KSS) is analysed. Fifty-one balanSys total knee arthroplasties were performed in 49 patients between 1998 and 2000. These arthroplasties are analysed with respect to AP laxity (Rolimeter), ROM and KSS with a mean follow-up of 4.6 years. The mean anterior laxity is 2.8 mm with no posterior laxities at all. The average postoperative ROM is 110 degrees with an average KSS of 142. No correlations between AP-laxity and postoperative ROM or between AP-laxity and postoperative KSS are found. A posterior cruciate retaining TKA with a relative dished insert and implanted with a tensor is very stable in the anterior-posterior direction in 30 degrees of knee flexion. This limited laxity does not seem to disadvantage the mean postoperative ROM and KSS, when compared to other TKA studies.

Step-cut tibial tubercle osteotomy for access in revision total knee replacement

In this retrospective cohort, the results of step-cut tibial tubercle osteotomy (TTO) in 39 revision total knee arthroplasty, using the Continuum Knee System (CKS), are determined. In 39 revision, total knee arthroplasties, adequate exposure was obtained after step-cut TTO. All knees were recently reviewed for clinical and radiological results. Symptomatic TTO-related complications occurred in three out of 39 patients. Two patients had proximal migration of the tibial tubercle due to an insufficient step-cut. Another patient had posttraumatic avulsion of the tibial tubercle. No TTO-related extensor lag or tibial fracture occurred We conclude that, when adequate exposure cannot be obtained, step-cut TTO is a safe and reproducible procedure if strict attention is paid to technique and fixation. It does not compromise the functional results of TKA.

Retention versus sacrifice of the posterior cruciate ligament in total knee replacement for treatment of osteoarthritis and rheumatoid arthritis

BACKGROUND

The functional and clinical results to support the choice whether or not to retain the posterior cruciate ligament (PCL) during total knee arthroplasty have not been gathered and analysed so far. There are at least some trials showing no difference.

OBJECTIVES

To identify the difference in functional, clinical, and radiological outcome between retention and sacrifice of the PCL in total knee arthroplasty in patients with osteoarthrosis and other non-traumatic diseases.

SEARCH STRATEGY

A search was conducted in MEDLINE(Through PubMed; 1966 - March 2004), EMBASE (1980 - March 2004), Cochrane Central Register of Controlled Trials (CENTRAL Issue 2004 - 1), and Current Contents (1996 - March 2004). Also, references of selected articles were checked and citation tracking on the articles selected was performed.

SELECTION CRITERIA

Randomised controlled trials comparing retention to sacrifice of the PCL during total knee arthroplasty with regard to functional, radiological and clinical outcome in patients with osteoarthritis and other non-traumatic diseases were selected by two independent reviewers.

DATA COLLECTION AND ANALYSIS

Methodological quality was assessed with the checklist by van Tulder and the Jadad list. Data was collected with a predeveloped form. Meta-analysis was performed with subgroup analyses on age, gender, disease severity, and follow-up time, if allowed by adequate power.

MAIN RESULTS

Eight randomised controlled trials were found. Two treatment options were compared against PCL retention: PCL sacrifice without additional stabilisation (post and cam mechanism) (2 studies), and PCL sacrifice with posterior stabilized design (5 studies). One study included all three options. Range of motion was found to be 8.1 degrees higher in the posterior stabilized group compared to the PCL retention group (p=0.01, 95% confidence interval [1.7, 14.5]), although the heterogeneity was high (I(2 )= 66.3%). PCL resection without substituting the PCL with a posterior stabilised prosthesis showed no difference compared to PCL retention (p=0.31, I(2) = 83.2%). On clinical scores, only Hospital for Special Surgery score revealed a significant difference of 1.6 points (p=0.03, 95% confidence interval [-3.1, -0.1]) between PCL retention versus PCL sacrifice and substitution combined favouring the latter group. The necessary subgroup analyses could not be performed for the clinical scores.

AUTHORS' CONCLUSIONS

These results should be interpreted with caution as the methodological quality of the studies was highly variable. We conclude that there is, so far, no solid base for the decision to either retain or sacrifice the PCL with or without use of a posterior stabilized design during total knee arthroplasty. The technique of PCL retention is difficult because the normal configuration and tension need to be reproduced with ligament tensioners. Knowledge of the technique needs to be improved before it can yield superior results compared to the more straightforward techniques of PCL sacrifice or use of a posterior stabilized design. Also, studies evaluating the effect of both techniques should address the right outcome parameters such as range of motion, contact position, and anterior-posterior stability. Suggestions are given to improve future research on this specific topic of knee arthroplasty.

Distal tuberosity osteotomy in open wedge high tibial osteotomy can prevent patella infera: a new technique

To prevent patella infera in open wedge high tibial osteotomy, a new operation technique was developed. Instead of a proximal tibial tuberosity osteotomy, a distal osteotomy was performed and the tuberosity was fixed with one screw to the tibia. Initial experience in 17 patients was evaluated and compared with results of 20 patients with open wedge high tibial osteotomy with proximal tuberosity osteotomy. Distal tuberosity osteotomy in open wedge high tibial osteotomy appears effective in preventing patella infera.

Methodology and reporting of randomised controlled trials

A systematic review of the literature will fail to provide information needed for evidence-based medicine (EBM) if the design, execution and reporting of individual trials do not adhere to strict guidelines. Experience gained while conducting systematic literature reviews have revealed serious shortcomings in current literature. These limitations pertain to randomisation, blinding, outcome assessments and data reporting. The principles related to these issues are discussed with solutions and improvements provided.

Single or double-level anterior interbody fusion techniques for cervical degenerative disc disease

BACKGROUND

The number of surgical techniques for decompression and solid interbody fusion as a treatment for cervical spondylosis has increased rapidly, but the rationale for the choice between different techniques is unclear.

OBJECTIVES

The goal of this study was to determine which method of anterior cervical interbody fusion at a single or double-level provides the best clinical and radiological outcome in patients with degenerative disc disease.

SEARCH STRATEGY

Studies were identified with a computer-assisted search of electronic databases in the Cochrane Central Register of Controlled Trials (Issue 1, 2004), MEDLINE (1966 to 2004), EMBASE (1980 to 2004), and Current Contents (1996 to 2004). We also searched references of selected articles.

SELECTION CRITERIA

With the aid of a checklist, two reviewers independently screened the identified references. Consensus was reached through negotiation. A third reviewer was consulted if consensus could not be reached. Inclusion criteria included: articles were reports of randomised comparative studies; treatments compared anterior cervical decompression and interbody fusion techniques, participants were individuals scheduled for surgery for a chronic (longer than 12 weeks) diagnosis of degenerative disc disease.

DATA COLLECTION AND ANALYSIS

Methodological quality was assessed independently by two reviewers, using the van Tulder list of criteria. With the aid of a data extraction form, data was extracted independently by two reviewers on group characteristics, intervention details and outcome measures.

MAIN RESULTS

Fourteen studies with 939 patients evaluated three comparisons of different fusion techniques. From these comparisons it appears that discectomy alone has a shorter operation time, hospital stay, and post-operative absence from work than discectomy with fusion, while there is no statistical difference for pain relief and rate of fusion. It also appears that fusion techniques that use autograft give a better chance for fusion than interbody fusion techniques that use a cage, but other outcome variables could not be combined.

REVIEWERS' CONCLUSIONS

The low quality of the trials prohibits extensive conclusions from this review. More studies with better methodology and reporting are needed. There should be a more general agreement between researchers on which outcome parameters should be used in the evaluation of anterior cervical fusion procedures.

Total disc replacement for chronic low back pain: background and a systematic review of the literature

In this paper the rationale for total disc replacement is discussed, and the authors suggest seven requirements that should be met before the implantation of these devices can be accepted as regular procedures. In an attempt to answer the questions raised, a systematic literature search was performed. The search yielded no controlled trials and nine case series with a total of 564 arthroplasties in 411 patients. The devices used were SB Charité in eight and Acroflex in one study. The percentage results classified as "good" or "excellent" in the studies varied from 50 to 81%. Complications were observed in 3-50% of the patients. Twenty-two of the operated levels were fused either spontaneously or after additional surgery. A meta-analysis to compare the results with other treatments could not be performed due to the lack of comparative studies. Despite the fact that these devices have been implanted for almost 15 years, on the basis of this literature survey there are currently insufficient data to assess the performance of total disc replacement adequately. There is no evidence that disc replacement reliably, reproducibly, and over longer periods of time fulfils the three primary aims of clinical efficacy, continued motion, and few adjacent segment degenerative problems. Total disc replacement seems to be associated with a high rate of re-operations, and the potential problems that may occur with longer follow-up have not been addressed. Therefore, total disc replacements should be considered experimental procedures and should only be used in strict clinical trials.

Pain and function after intradiscal electrothermal treatment (IDET) for symptomatic lumbar disc degeneration

The goal of this study was to evaluate the short-term effects of intradiscal electrothermal treatment (IDET) for chronic discogenic low back pain. Twenty consecutive patients with symptomatic degenerative discs were treated with IDET and evaluated preoperatively, and 3 and 6 months postoperatively. Pain was measured with a 100-mm visual analog scale (VAS) and function was evaluated with the Oswestry score and SF-36 questionnaire. The VAS scores improved by 14 mm on average (P=0.046), but the individual scores show great variation. The Oswestry scores did not improve significantly. The SF-36 showed improvement, but only for the subscales vitality (P=0.023) and bodily pain (P=0.047). Based on these results, we conclude that IDET is not effective in reducing pain and improving functional performance in a sample of 20 patients treated for chronic discogenic low back pain after 6 months follow-up.

Anterior lumbar interbody fusion with threaded fusion cages and autologous bone grafts

The goal of this study was to evaluate the ability of Ray threaded fusion cages, when used in an anterior approach, to restore intervertebral height and to improve the functional and occupational performance of the patients. The present study was initiated because insertion of fusion cages through a posterior approach causes destruction of facet joints and violation of the spinal canal. The anterior approach for insertion of threaded fusion cages to accomplish lumbar interbody fusion was evaluated in a series of 13 patients suffering monosegmental disc disease. The patients' functional and occupational performance was evaluated using the Prolo score. Radiological measurements were used to evaluate disc height and degree of penetration into the endplates, and to confirm fusion. Seven of the 13 patients were short-term failures and had to be revised within 2 years. The study found that revised patients had poorer Prolo scores than non-revised patients. Although for the non-revised patients, the mean Prolo scores remained relatively stable during the 1st year, they dropped after 3 years. We were not able to identify any further clinical or radiological differences between the groups. These results indicate that although the anterior approach seems technically suitable for insertion of threaded fusion cages, destruction of the anterior longitudinal ligament and the anterior part of the annulus fibrosis appears to result in destabilisation of the motion segment.