Relationships between clinical, biomechanical and

Eur J Orthop Surg Traumatol DOI 10.1007/s00590-007-0234-0

O R I G I N A L A R T I CL E

Relationships between clinical, biomechanical and psychosocial parameters in outcome assessment, 7 years after posterolateral lumbar fusion S. Champain · V. Pointillart · M. Koleck · O. Gille · J. M. Vital · C. Mazel · W. Skalli

Received: 19 December 2006 / Accepted: 15 March 2007 © Springer-Verlag 2007

Abstract Though well described in the literature, technical and clinical results of posterolateral fusion (PLF) in degenerative lumbar spine do not always reXect patient’s perception of outcome or satisfaction. Several tools were proposed for an objective outcome assessment: clinical scores, questionnaires investigating psychosocial factors and biomechanical X-ray Wlms based analysis, but studies combining these topics were limited and rarely conducted. The present study aimed to preliminarily evaluate the relationship between clinical, psychosocial and biomechanical parameters in long-term outcomes assessment after PLF. Clinical, psychosocial and radiological data were analyzed for 26 patients, with a follow-up of 7 years. Satisfactory results were found in 85% of patients. Anxiety, functional impairment, psychological distress and perceptual health were signiWcantly diVerent in studied and control groups. Biomechanical analysis outlined 19% of pseudarthrosis and 58% of abnormal spine geometry (mainly imbalance) at 7 years follow-up. Clinical and biomechanical Wndings

S. Champain (&) · W. Skalli Laboratory of Biomechanics, ENSAM, 151, Boulevard de l’Hôpital, 75013 Paris, France e-mail: [email protected] V. Pointillart · O. Gille · J. M. Vital · C. Mazel Orthopaedic Surgery and Traumatology Unit, CHU Tripode, Bordeaux, France M. Koleck Psychology Unit EA 3662, University Victor Segalen, Bordeaux, France C. Mazel Institute Mutualist Montsouris, Paris, France

were not in agreement with patient’s perceptual health and satisfaction in 38% of cases, where cross-analysis of clinical, psychosocial and biomechanical parameters gave a better description of outcomes. In conclusion, the use of several simple parameters (clinical, psychosocial and biomechanical) allows for a complementary analysis for a given patient and seems to oVer a more accurate appreciation of the global outcome. Keywords Spine · Fusion · Outcome · Psychosocial · Biomechanics · Quantitative

Relations entre paramètres cliniques, biomécaniques et psychosociaux dans l’évaluation des résultats 7 ans après arthrodèse lombaire postéro-latérale Résumé Largement décrits dans la littérature, les résultats cliniques des arthrodèses postéro-latérales (APL) du rachis lombaire dégénératif ne réXetent pas toujours le résultat ou la satisfaction ressenties par le patient. Pour une évaluation objective, plusieurs moyens d’analyse ont été proposés: scores cliniques, questionaires investiguant les facteurs psychosociaux ou analyse biomécanique basée sur des radiographies, mais les investigations combinant ces outils ont été rares et limitées. La présente étude a eu pour but l’analyse préliminaire des relations entre les variables cliniques, psychosociales et biomécaniques dans l’évaluation des résultats des APL à long terme. Ces variables ont été analysées pour 26 patients, avec un recul de 7 ans, mettant en évidence des résultats satisfaisants en 85% de cas. L’anxiété, les limitations fonctionnelles, la détresse psychologiques et la santé perceptuelle étaient signiWcativement diVérentes entre le groupe étudié et un group témoin. L’analyse biomécanique a mis en évidence 19% de

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Eur J Orthop Surg Traumatol

pseudarthrose et une géomètrie anormale du rachis en 58% des cas à 7 ans de suivi (principalement deséquilibre). Les résultats cliniques et biomécaniques ont été en dissonance avec la santé perceptuelle et la satisfaction du patient en 38% des cas, ou l’analyse croisée de paramètres cliniques, psychosociaux et biomécaniques a fourni une meilleure description des résultats. En conclusion, l’utilisation des plusieurs paramètres simples (cliniques, psychosociaux et biomécaniques) permet une analyse complémentaire pour un patient donné et semble oVrir une meilleure appréciation du résultat global. Mots clés Rachis · Fusion · Résultat · Psychosocial · Biomécanique · Quantitative

Introduction In the last decades, clinical criteria of successful outcomes for posterolateral fusion (PLF) were largely presented in the literature [51, 57], focusing on one or several of the following variables: complications, fusion [7, 13, 32], back and leg pain [2], return to work [19, 39, 56] and functional status [8, 49], without reaching to an agreement for key factors or “standard” outcome assessment. DiYculties in assessment may also arise from a diVerent perception of long-term outcomes between the patient and his orthopaedic surgeon [11], as some patients considered as technical success may still experience pain and dysfunction, causing a lower satisfaction [9, 33]. In this context, several studies [8, 21, 26, 33, 36] underlined the importance of psychosocial variables in outcome assessment, allowing for a more accurate evaluation of patient’s perceptual health, outcome and medical costs [8, 14, 33, 54]. Furthermore, in order to ensure a more complete and objective evaluation, several scores were proposed, either generic (i.e. SF-36, NSP/ISPN [4, 23, 55]), either focused on speciWc factors inXuencing the outcome: pain, functional disability, socioprofessional and psychological. On the other hand, quantiWed analysis of parameters from routine X-ray Wlms [5, 35, 37, 40, 48, 52] is more and more implemented in support for clinical exams, allowing to objectively describe speciWc patients’ biomechanical conWgurations. However, though a relationship between clinical, psychosocial and biomechanical parameters was intuitively considered, especially in work-related analysis [28], these three dimensions of the global outcome were not objectively and simultaneously analyzed yet. The aim of the present study was to preliminarily investigate the relationship between clinical, biomechanical and psychosocial parameters in long-term outcomes evaluation after posterolateral lumbar fusion.

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Material and methods Population sample This retrospective study concerned 60 patients surgically treated by posterolateral lumbar fusion at CHU Tripode (Bordeaux) in 1987, by the same senior surgeon (JM V). Main indication was discogenic low back pain, not responding to conservative treatment, excluding patients with diagnosed psychological distress and scoliosis. From the complete Wles conserving both clinical and radiological data, 26 patients could be located 7 years after surgery and accepted to come for a long-term evaluation. They were 16 men and 10 women, mean age 53 years (range 26–77), suVering at surgery time for back and leg pain, caused by spondylolisthesis in 38% of cases, by recurrent disc herniation in 27% of cases and by pure degenerative disc disease in the other 35% of cases. At the surgery time 18 patients (69%) were employed and 8 (31%) retired; from the employed patients, 16 were in sick leave at the preoperative consultation time. Addictive behaviour was noted in seven cases for tobacco and in three other cases for alcohol (especially in aged patients). Posterolateral lumbar fusion was performed, as described in the literature, at the following levels: L4S1 34, L5S1 31, L4L5 35%. In 35% of cases fusion was uninstrumented and in the other 65% of patients rigid transpedicular rod/screw instrumentation was used (Diapason®, Stryker, France). Mean follow-up was of 7 years (range 6.5–7.5 years). Data collection and methods The long-term (7 years) clinical evaluation was performed by two orthopaedic surgeons (V P and O G), not involved in the surgery. An independent observer (SC) collected and analyzed in a blinded fashion general, clinical, socioprofessional, psychosocial and radiological data for all patients. General and clinical data involved: antecedents, comorbidity, addictive behaviour, physical activity, analgesics, pain (type, duration, percentage of postoperative improvement) and per and post-operative complications. Socioprofessional data involved: type of work, return to work and family support. Psychosocial factors and quality of life were investigated in collaboration with the health psychology team of University Bordeaux 2 Victor Segalen (France), at 7 years follow-up, using four validated and reliable questionnaires, presented in the following. The State Trait Anxiety Inventory (STAI) of Spielberger [3, 16, 46] is composed of 2 subscales of 20 questions each, allowing to evaluate anxiety in two time dimensions: at the


moment of investigation, as temporary process: “state-anxiety”, and in general, as general trends toward anxiety: “trait anxiety.” Answers range from 1 to 4 points on a Likert scale and global results may vary from 20 to 80 proportionally with an increasing level of anxiety. Same “state”– “trait” dimensions were investigated with two versions of the Centre for Epidemiologic Studies Depression Scale (CES-D) [15, 17, 31, 41] in order to detect and quantify depression. Answers are ranging from 0 to 3 for each of the 20 items and total sum may vary between 0 and 60. Values of the state-depression score being considered signiWcant of depressive symptoms are superior to 17 for men and superior to 23 for women. The French version of the Nothingham Health ProWle [23] (ISPN [4, 42]) was also used, as it allows quantifying functional impairment from questions investigating pain and physical mobility and psychological distress from questions on social isolement, emotional reactions, sleep and energy. Furthermore, the MOS SF-20 questionnaire (a short form of SF-36) [36, 55] allowed to evaluate functional impairment, patient’s well-being and perceptual health. Reference values: In addition to some references published in literature for psychosocial factors, all the abovementioned parameters were also calculated from a control group, which was composed of 26 asymptomatic subjects, mean age 48 years (range 22–65), with a composition matching to that of our population. Clinical outcome was investigated using the StauVer– Coventry index [47], based on clinical data recorded in patient’s Wle and those collected at 7 years follow-up, for the entire population. This index evaluates pain relief, work status, restriction of physical activities and analgesic medication use. For each category, outcome was evaluated on the following criteria [33]: (1) good: 76–100% relief in leg and back pain, return to previous work status, minimal or no restrictions of work activities, occasional mild or no analgesics; (2) fair: 26–75% relief of leg and back pain, return to lighter work, moderate restrictions of physical activities, regular use of non-narcotic analgesics and (3) poor: 0–25% relief of leg and back pain, no return to work, severe restrictions of physical activities, occasional or regular use of narcotic analgesics. Lowest rated outcome of the four items designated the global outcome. These results were compared to the 7 years subjective outcome evaluated by the orthopaedic surgeons (V P and O G). Patient’s satisfaction [9] was also investigated at 7 years follow-up, using two questions answered by yes/no, evaluating patient’s satisfaction concerning the surgery and if he/ she would undergo same surgery for same result. Radiological data were retrospectively collected as follows: Lumbar dynamic (Xexion-extension) X-ray Wlms were available in preoperative exam and at 1 year follow-up for

all patients. Sagittal standing full spine radiographs were available for all 26 patients in preoperative, short-term (0– 1 year), mid-term (1–2 years) and long-term (7 years) exams. For the early postoperative follow-up, the 1 year X-ray Wlms were selected, in order to reXect as close as possible the sagittal geometry at the moment where dynamic X-ray Wlms were taken (to correspond to the moment of fusion evaluation). Globally, 104 sagittal standing full-spine and 62 lumbar Xexion-extension X-ray Wlms were scanned and then analyzed using speciWc software (SpineView 2.0®, Surgiview, France). The analysis is based on anatomic landmarks identiWcation on the scanned image, generating a large range of parameters, whose validity and accuracy were previously established [5]. Main parameters calculated from radiographs will be detailed in the following, covering two main topics. Lumbar dynamic (Xexion–extension) analysis The range of motion (ROM) represents the angular Xexion– extension mobility for a given intervertebral segment, calculated with an accuracy of 2° [5]. With regard to the fused segment, ranges of motion quantify the residual mobility [38] and allow to class fusion as solid for ROM < 3°, doubtful for ROM ranging between 3° and 5° and as pseudarthrosis when ROM > 5° [6]. The mean centre of rotation describes the Xexion–extension movement between two adjacent vertebras, expressed as the position (X, Y coordinates) of its axis in a Cartesian system applied to the lower vertebra (see Fig. 1) [40, 45]. This position cannot be accurately calculated for ROM < 3° [48]. Reference values for these parameters were available from a previous study [6] and allowed to evaluate kinematic patterns of each intervertebral level. Sagittal geometry and balance Sagittal spine geometry was described by the following parameters [35, 52]: T4T12 kyphosis (angle between the superior endplate of T4 and the inferior one of T12), L1S1 lordosis (angle between the superior endplate of L1 and the sacral plate), Total Lumbo-Pelvic Lordosis PR-T12 (TLPL, angle between the lower endplate of T12 and the segment uniting the middle of the bicoxo-femoral axis to the postero-superior corner of S1) [24], as well as pelvic parameters sacral slope (sacrum inclination to the horizontal) and incidence (angle between the segment uniting the centre of the bicoxo-femoral axis to the middle of sacral plate and the perpendicular to the sacral plate in its middle) [35,37]. In order to evaluate balance, global inclination was calculated, as the angle between the straight line interpolating

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Fig. 1 Mean centre of rotation (MCR) [40, 45] in lumbar Xexion– extension analysis

the centres of all vertebras (C1–S2) and the vertical (Fig. 2). Reference values and mean errors of measurement for a 95% conWdence interval [5] are presented in Table 1 for the above parameters. Statistics Fig. 2 Global inclination [5]

Descriptive statistics were used to characterize all parameters. Paired Student’s t test was used to evaluate any statistically signiWcant diVerence between parameter values calculated at diVerent moments of the follow-up, thus highlighting their evolution. Unpaired t test was used to compare treated and control populations in the analysis of psychosocial variables. Pearson’s and Spearman’s tests were used to evaluate the eventual correlations (only for P < 0.001 because of the low sample) between calculated parameters and their relationship with global outcome. SigniWcance was set at P = 0.05 and all tests were performed by means of Statview® (SAS Institute, USA) software.

Results Clinical outcome At 7 years follow-up, patients reported a low back pain absent or very light in 39% of cases, mild in 38% and severe in 23% of cases.

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Complications rate was of 27% in this population (7 cases), represented by: screw breakage in three cases, infection needing material removal in one case, and adjacent level degeneration in four cases (in one of this latter cases screw breakage occurred also). Revision surgery was performed without further complications in 5 (19%) of these cases. Socio-professional data from the employed patients, 83% could return to work after the Wrst year and a third of them resumed their previous activities at the same level, the others having to reconvert to a less diYcult job. The retired ones resumed their daily activities within the Wrst year after surgery but limitations were self-imposing in most cases. All patients but one declared to have had the support of their family after the surgery (one patient divorced). Psychosocial variables and quality of life Globally, a statistically signiWcant diVerence was found between the treated population and the control asymptomatic group for the psychosocial variables: anxiety, functional impairment,

Eur J Orthop Surg Traumatol Table 1 Reference and mean values for spinal and pelvic parameters during time, presented as mean § standard deviation Measurement errora

Normal values [5]

T4T12 kyphosis

5.2°

Lordosis

4.4°

TLPL

Variable (°)

Follow-up exam Before surgery

1 year

7 years

39 § 8

¡34 § 10

¡35 § 9

¡37 § 11

57 § 11

49 § 16

47 § 18

50 § 13

2.4°

92 § 9

80 § 9

77 § 10

75 § 15

Global inclination

0.1°

0§3

2§4

3§4

6§5

Sacral slope

4.0°

39 § 8

36 § 10

34 § 11

37 § 10

Incidence

3.4°

51 § 11

57 § 11

57 § 11

59 § 8

a

For a 95% conWdence interval

psychological distress and perceptual health. Depression levels were not signiWcantly diVerent in the two groups; they were higher than reference in six patients and associated, in four of them, with anxiety levels signiWcantly higher than those of asymptomatic subjects. All investigated psychosocial factors were intercorrelated, most signiWcant relations being observed between: state-anxiety–trait-depression, psychological distress–wellbeing and also functional impairment–perceptual health (r = 0.7–0.8), the relation being inversed for the last two couples. Global clinical outcomes issued from StauVer–Coventry score were good in 46% of patients, fair in 39% and poor in other 15% of patients. There was no statistically signiWcant diVerence between outcomes quantiWed with StauVer–Coventry score and the subjective ones (surgeon-reported), still the amount of good and poor results were slightly diVerent, as can be seen on Table 2. Patients’ satisfaction was reported as follows: very satisWed in 16 cases (62%) moderately satisWed in six cases (23%) and unsatisWed in four cases (15%), which would not undergo same surgery for same result. Radiological analysis Lumbar Xexion–extension analysis The analysis of ranges of motion and mean centres of rotation allowed to quantify residual mobility of the fused segment and kinematic patterns of the other levels at about 1 year follow-up. With regard to the fused segment, the ranges of motion were inferior to 3° in 17cases (66%), assigned as solid fusion, between 3 and 5° in 4 cases (15%), classed as doubtful fusion and superior to 5° in 5 cases (19%), signiWcant of a pseudarthrosis (screw breakage occurred in 2 of these 5 cases). Kinematic patterns were normal in 19 cases (73%) for the adjacent levels and in 16 cases (62%) for the levels above upper adjacent; abnormal patterns were characterized by mobility lower than 5° and abnormal MCRs.

Sagittal standing X-ray Wlms analysis Student’s t and Fisher z tests showed a statistically signiWcant diVerence between values calculated at 1 year and at very long term for global inclination. No evolution was statistically highlighted for other parameters or moments of the follow-up. Globally, spinal and pelvic parameters values (presented in Table 1) were between normal ranges in 17 cases (73%) before surgery and in 18 patients (69%) for all postoperative exams. Main situations where abnormal values occurred are discussed in the following: • Lordosis and pelvic parameters (especially sacral slope) were lower than reference values and associated to a Xat back syndrome in Wve patients (19%) during time, with no signiWcant evolution. • High values of pelvic parameters, characteristically to spondylolisthesis patients [37] were found before surgery in four patients and postoperatively in two of them (at all exams). • Low values of TLPL were found in Wve patients during all follow-up: in three cases they were associated to Xat back syndrome and low satisfaction levels and in the other two with spondylolisthesis. • High values of kyphosis were found at long term in two patients, associated with aggravating imbalance. Normal balance was found before surgery in 22 cases, at 1 year in 23 and at long-term exam in 15 cases; in the latter exam the 11 patients (42%) presenting high values of global inclination were bending forward. Lordosis and pelvic parameters were intercorrelated in all exams (r = 0.8–0.9), in agreement with literature [35, 37, 52]. T4T12 kyphosis was correlated with TLPL (r = ¡0.6) before surgery and with global inclination (0.7) at 7 years follow-up. Age was correlated with global inclination in preoperative and long-term exams (r = 0.6), with lordosis in preoperative and short-term exams (r = ¡0.5) and with T4T12

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Relationship between clinical, biomechanical and psychosocial variables Subjective and objective graded clinical outcomes were concordant with patients’ satisfaction and perceptual health only in 62% of cases. Main situations encountered in the other 38% of cases were (Table 2): • Good clinical outcomes and normal biomechanical parameters associated with low satisfaction and perceptual health (6 cases) or • Low clinical outcomes, complications and abnormal biomechanical parameters associated with good satisfaction levels (4 cases). A typical example for each situation is presented in Fig. 3. The relationship between psychosocial variables, biomechanical parameters and clinical outcome is represented in Fig. 4, as resulting from the correlation matrix (Pearson’s test, P < 0.001). Satisfaction was correlated with outcomes (r = 0.6), functional impairment and perceptual health (r = 0.5). No correlations were found between outcomes and antecedents, physical activity or addictive behaviour and only a weak one with comorbidity (r = 0.4, P < 0.001). Back pain was correlated with outcomes, complications and acquired adjacent level degradation (r = 0.6) and also with anxiety and perceptual health (r = 0.5).

Discussion

Fig. 3 Examples of disagreement between clinical outcomes, biomechanical analysis and patient’s satisfaction. a B.M., men, 73 years, L4S1 fusion, fair outcome, inferior screws broken, pseudarthrosis, imbalance, feels satisWed and very much improved, considers himself as a good result and having a good health 7 years after surgery. b D.M., woman, 50 years, L5S1 fusion, good outcome, no complications, solid fusion, feels less satisWed and only a little improved, considers herself as a mean result though having a good health 7 years after surgery

kyphosis (r = ¡0.6) at 7 years follow-up. Moreover, at long-term exam, adjacent level degeneration was correlated with lordosis, TLPL (both r = ¡0.5) and global inclination (r = 0.5).

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Limits of the study, such as the heterogeneity of pathologies and treated levels, focused the analysis on the general condition of common degenerative spine treated by PLF, which is a justiWed option for a preliminary study. Moreover, as many authors found no signiWcant diVerence between the results of instrumented and uninstrumented fusion regarding clinical outcomes [10, 27], pain [2] or fusion [7, 39, 49], global outcomes could be evaluated without separate consideration in studied patients. Therefore, in spite of the low sample size and of these limitations, Table 2 Clinical outcomes: comparison between subjective and objective grading, expressed as percentage of patients in each category Clinical outcome

Subjective (surgeon reported)

Objective (StauVer–Coventry index)

Good

54

46

Fair

38

39

Poor

8

15

Eur J Orthop Surg Traumatol Fig. 4 Correlations between clinical outcomes, psychosocial variables and biomechanical parameters

the authors decided to present this preliminary analysis, as it oVers for the Wrst time a general insight of long-term global outcomes after PLF, by simultaneous clinical, psychosocial and biomechanical evaluation. The eYcacy of PLF in our patients plays an important role in our multidimensional analysis, though it is not considered representative for general outcomes of PLF, so a comparison with published data on PLF was necessary. Various outcome assessment methods are presented in literature [13, 19, 32, 49, 51, 56], generating variable success rates: in a meta-analysis of 47 studies, Turner et al. [51] evaluated the range of outcomes to 16–95% (mean 68%) and the fusion rate at 85.6% (56–100%). The rates of 81% for fusion and 85% for satisfactory outcomes obtained in our study are comparable to these results. Moreover, they found a positive relation between solid arthrodesis and satisfactory clinical outcome, in agreement also with a study of Finkenberg et al. [13] who evaluated fusion with an intrasegmental Wxation system at 2 years postoperatively on 259 patients and obtained 88% fusion rate and 89% satisfactory outcomes. Conversely, Grubb [19] and Zdeblick [56] found diVerent outcomes related to fusion comparing to those issued from the evaluation of pain and of return to work, diVerences that seem to be in agreement with our Wndings, which outlined a strong relation between outcomes, back pain, complications and acquired degeneration of the adjacent level. However, though the assessed outcomes were in agreement with literature, they do not explain situations when patient’s level of satisfaction and clinical outcome were diVerent, that seem to be more related to diYculties of job conversion, quality of life and variable pain perception. Strong evidence has been obtained that psychosocial factors may have a signiWcant inXuence on return to work [22, 28, 43, 50, 53], pain perception in low back pain and devel-

opment of pain chronicity [21, 26]. In order to detect predictive factors of an unsatisfactory outcome, some authors proposed biopsychosocial models using presurgical variables like depression [8, 33], anxiety [18] and older age [8]. However, such models require extensive and complex questionnaires, which are diYcult to use systematically in routine clinical examination. In our study, four validated questionnaires were chosen by a team of psychologists, in order to investigate a panel of parameters including anxiety, depression, functional impairment, well-being, psychological distress and perceptual health. As presurgical screening of psychosocial variables was not available (retrospective study), depression and anxiety were investigated in two time dimensions, in order to detect the level that generally characterizes a given patient when reporting the one calculated in long-term evaluation. Furthermore, some intercorrelations were observed between all variables, especially between psychological distress—well-being and functional impairment—perceptual health (r = ¡0.7–0.8), suggesting a certain complementarity between ISPN and MOS-SF-20; therefore, the number of questionnaires needed for this evaluation may be reduced at three (STAI, CES-D and MOS SF-20). They allowed detecting the parameters speciWcally describing our population, which were anxiety, functional impairment, psychological distress and perceptual health, conversely to depression and well-being, which were surprisingly not statistically diVerent in the two populations. Another dimension of our analysis was represented by biomechanical analysis, who “drawed” an objective view of long-term patients’ conWgurations after posterolateral fusion, basically discussed in the following. Thus, quantitative Xexion–extension analysis allowed for an accurate estimation of fusion rate (established at 81% in this population) and of adjacent levels mobility, which was lower than 5° in

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27% of cases, suggesting an increased lumbar stiVness. Sagittal analysis highlighted few relevant abnormalities in patient’s evolution: in addition to some cases of spondylolisthesis or Xat back syndrome, constant in time, there were 11 cases (42%) of long-term postoperative imbalance. They have to be associated not only to the eVect of surgery but also with the long-term age-related evolution of kyphosis and global inclination, in agreement with other published studies [8, 25]. Moreover, the fact that kyphosis was correlated with TLPL before surgery and with global inclination at long-term exam might reXect a change in balance mechanisms that would be interesting to investigate in a larger scale prospective study. Furthermore, in addition to the correlations between lordosis and pelvic parameters, already described in literature [35, 37, 52], TLPL and lordosis were correlated with clinical outcome (issued from StauVer–Coventry index) and also with adjacent level degeneration (r = ¡0.6). This may suggest a relation between low lordosis values (same for TLPL), adjacent level degeneration and lower outcomes and seem to be in agreement with studies of Schlegel et al. [44] and Akamaru et al. [1], who showed that incorrect sagittal alignment or hypolordotic Wxation of a lumbar fusion causes degeneration at the above adjacent level. When discussing the relationship between clinical outcome, psychosocial factors and biomechanical parameters, comparison with literature is very diYcult because most studies evaluated at most relations between clinical outcome and fusion, adjacent level degeneration or sagittal alignment [20, 34] or between some psychosocial factors and low back pain [26, 43]. A study of Lazennec et al. [34] investigated on clinical and few biomechanical parameters, Wnding a relation between pain, outcome and deWcient sagittal alignment. In our series, lordosis and TLPL were correlated with clinical outcomes, state-anxiety and functional impairment at long-term exam, which seem to be in agreement with the above Wndings. The relations between functional impairment and preoperative global inclination, short-term lordosis and longterm TLPL on one hand and between state-anxiety and postoperative lordosis, TLPL and sacral slope on the other hand may suggest that low values of these biomechanical parameters, reXecting abnormal spine geometry, are related to restrictions of activities and may result in increasing anxiety or depression for the patient. As depression has been consistently associated with unsatisfactory outcome [17, 21, 26, 43], especially when linked to lower levels of social support, increased stress [33] and inactivity [12], this may explain some cases of poorer satisfaction and perceptual health. Another interesting point came from patient’s interview, as it seem that some patients that entertained good daily physical activities (gardening,

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walking, shopping) reached to good long-term results, in spite of possible complications. This fact is consistent with Wndings of Kjellby et al. [29], who showed that rehabilitation aVects pain interference and of Junge et al. [26], who highlighted the role of physical activities in Wghting depression and the need to implement them in coping strategies [21, 30]. Nevertheless, patients with a strong feeling of well-being seemed to cope more easily with functional impairment and pain; they may perceive a better quality of life and outcome than those estimated clinically and/or biomechanically, as reXected by their longterm perceptual health and satisfaction. The inXuence of all these confounding factors may partially explain cases when the patient considered that lumbar surgery has not been successful even when the morphological problem has correctly been addressed by surgery, in agreement with a hypothesis of Schade et al. [43]; therefore, though a complete analysis may be a little complex, it may accurately evaluate and explain the cases when clinical or biomechanical results and patient’s satisfaction and perception of outcome were in disagreement. These Wndings open the perspective of a complementary evaluation, where, in support for clinical exam, the quantiWed radiological analysis would oVer a objective evaluation of patient’s biomechanical conWguration and would monitor its clinically signiWcant changes, while the analysis of psychosocial factors would help to design personalized coping strategies, from the early postoperative exams, which might improve the long-term outcomes and patient’s satisfaction and reduce medical costs.

Conclusion The Wndings of the present study suggest that quality of life variables, even from a transversal approach like in this analysis, may oVer an insight in patient’s perception of outcome, related to satisfaction levels. Moreover, biomechanical analysis draws an objective view of patient’s conWguration and evolution, not only from the fusion point of view, but also from that of global spine geometry and balance, which seem to be related to functional impairment, anxiety and global outcome. In conclusion, the use of several simple parameters (clinical, psychosocial and biomechanical) allows for a complementary analysis for a given patient which is not redundant and seems to oVer a more accurate appreciation of the global outcome, in support for clinical exam. Acknowledgments The authors wish to thank C. Rumeau, A. Deplanche, A. Templier and A. Mitulescu for their precious help in data collection and SpineNetwork for their support (grant for a PhD project ruled by the National Agency for Technological Research (ANRT in French): CIFRE no 677/2002).


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