Disease burden of prosthetic joint infections after hip and knee joint replacement in Finland during 1999-2004: capture-recapture estimation.

We evaluated the Finnish Hospital Infection Program (SIRO) conducting incidence surveillance for prosthetic joint infection (PJI) from 1999 to 2004. We estimated its sensitivity using capture-recapture methods and assessed the disease burden of PJIs after hip (THA) and knee (TKA) arthroplasties (N = 13 482). The following three data sources were used: SIRO, the Finnish Arthroplasty Register (FAR), and the Finnish Patient Insurance Center (FPIC), which were cross-matched, and 129 individual PJIs were identified. After adjusting for the positive predictive value of SIRO (91%) a log-linear model including an interaction term between FAR and FPIC provided an estimated PJI rate of 1.6% [95% confidence interval (CI): 1.2-2.4] for THA and 1.3% (1.1-1.6) for TKA. Sensitivity for SIRO varied from 36% to 57%. The annual disease burden was 2.1 PJIs per 100 000 population after THA and 1.5 after TKA. The true disease burden of PJIs may be heavier than the rates from national sentinel surveillance systems usually suggest.

The effect of waiting time on health and quality of life outcomes and costs of medication in hip replacement patients: a randomized clinical trial.

OBJECTIVE: To evaluate the effect of waiting time on health and quality of life outcomes and costs of medication in total hip replacement (THR) patients in a randomized clinical trial. METHODS: 395 THR patients were recruited into the study. When placed on the waiting list, patients were randomized into a short (< or =3 months) or a non-fixed waiting time (NFWT) (>3 months) group. In the final analyses 309 patients (179 women) with a mean age of 65 years were included. Health-related quality of life (HRQoL) (generic 15D), and pain and function (modified Harris Hip Score (HHS)) were calculated when placed on the waiting list, at hospital admission, and at 3 and 12 months postoperatively. The costs of disease-specific medication were calculated at the same measurement points. All analyses were performed using the intention-to-treat (ITT) principal. RESULTS: Of the recruited patients, 309 (78%) completed the follow-up (short group 140 and non-fixed group 169 patients). The mean waiting time was 74 days in the short and 194 days in the NFWT groups. In the ITT analyses there were no statistically significant differences between the groups in the weekly use and costs of medication, HRQoL or HHS at baseline, at admission, or 3 or 12 months after surgery. The only difference was in total medication costs during the waiting time period, at EUR 83 and 171, respectively. CONCLUSIONS: The length of the waiting time did not generate different effects on the studied health and quality of life outcomes of the randomized groups. However, those in short waiting time group reached earlier better HRQoL.

Patient outcomes after simultaneous bilateral total hip and knee joint replacements.

Simultaneous arthroplasties are increasingly being performed during one single anaesthetic event. No national nosocomial surveillance systems have yet reported data on this issue. We compared patient populations undergoing bi- and unilateral total hip (THA) and total knee (TKA) arthroplasties in terms of two outcome variables, deep surgical site infections (SSI) and mortality, by analysing surveillance data from the Finnish Hospital Infection Programme (SIRO). A total of 8201 patients underwent 9831 total arthroplasties during 2001-2004. Of the prosthetic joints, 7.2% were inserted in a bilateral operation (range by hospital, 0.6-19.2%; range by procedure type, 5.2-9.9%). Patients who underwent bilateral operations were younger; more often males, and their ASA score was lower than those who underwent unilateral procedures. The rate of deep SSI in bi- and unilateral THAs and in bi- and unilateral TKAs was 0, 0.5, 1.0 and 0.9%, respectively. Following bilateral operations, four deep SSIs were detected, all from bilateral TKAs, three of which were on the second operative side. In these three cases, single doses of antimicrobial prophylaxis were administered 115, 155 and 218 min before incision (median time in unilateral operations: 47 min). According to multi-variate analysis, bilateral operations were not an independent risk factor for deep SSIs. Mortality did not differ between bi- and unilateral THAs or TKAs. Our surveillance data indicate that simultaneous bilateral surgery did not increase the risk of deep SSIs or death after THA and TKA. Bilateral operations may, however, require specific guidelines regarding antimicrobial prophylaxis.

Surgical versus conservative interventions for anterior cruciate ligament ruptures in adults.

BACKGROUND: Anterior cruciate ligament rupture is a common knee injury. Surgical treatment, usually involving reconstruction of the ligament, is widely used especially in active individuals. OBJECTIVES: Evaluation of the effect of surgical treatment compared with conservative treatment of anterior cruciate ligament (ACL) rupture. SEARCH STRATEGY: We searched the Cochrane Musculoskeletal Injuries Group Specialised Register (January 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2005), MEDLINE (1966 to January Week 3 2005), EMBASE (1988 to 2005 Week 05), MEDIC (1978 to January 1999), Current Contents (9.2.1998 to 1.2.1999), BIOSIS (1970 to December 1998), reference lists of articles and consulted trialists and experts. SELECTION CRITERIA: All randomised and quasi-randomised trials that compared surgical with conservative treatment of ACL rupture in adults. DATA COLLECTION AND ANALYSIS: Two authors independently performed study selection, data extraction and quality assessment. MAIN RESULTS: Two poor quality randomised trials conducted in the early 1980s were included in the review. The two trials differed considerably and no data pooling was done for the few shared outcome measures. One quasi-randomised trial of 167 people with a complete ACL rupture treated with repair or augmented repair versus conservative treatment found no difference in the return to sports activities between people treated surgically and those treated conservatively. Measures of knee stability and functional (Lysholm) knee scores were higher in surgically-treated participants. By the end of the follow-up period (average 55 months), three people treated with repair only and 16 treated conservatively had had ACL reconstruction. The other trial included 157 people with ACL injury. This found that conservatively-treated participants recovered from their injury more rapidly but, at the last follow up (minimum 13 months), the functional outcome was similar in both treatment groups. A large proportion of participants experienced some temporary discomfort after surgery and there were some more serious postoperative complications. There was less knee instability in surgically-treated participants and a tendency to fewer subsequent operations in the longer term. AUTHORS' CONCLUSIONS: There is insufficient evidence from randomised trials to determine whether surgery or conservative management was best for ACL injury in the 1980s, and no evidence to inform current practice. Good quality randomised trials are required to remedy this situation.

Radiofrequency denervation for neck and back pain. A systematic review of randomized controlled trials.

BACKGROUND: The diagnosis of cervical or lumbar zygapophyseal joint pain can only be made by using local anesthesia to block the nerves supplying the painful joint. There is a lack of effective treatment for chronic zygapophyseal joint pain or discogenic pain. Radiofrequency denervation appears to be an emerging technology, with substantial variation in its use between countries. OBJECTIVES: To assess the effectiveness of radiofrequency denervation for the treatment of musculoskeletal pain disorders. SEARCH STRATEGY: We searched MEDLINE, PsycLIT, and EMBASE from start to February 2002, plus the Cochrane Library 2002, Issue 2. The references of identified articles were checked and three experts in the field of radiofrequency treatment were consulted to identify studies we might have missed. SELECTION CRITERIA: Randomized controlled trials (RCTs) of radiofrequency denervation for musculoskeletal pain disorders, with no language or date restrictions. DATA COLLECTION AND ANALYSIS: Two reviewers selected RCTs that met predefined inclusion criteria, extracted the data, and assessed the main results and methodological quality of the selected trials, using standardized forms. Qualitative analysis was conducted to evaluate the level of scientific evidence. MAIN RESULTS: We found only nine articles, reporting on seven relevant RCTs. Six of the seven were considered to be high-quality. The selected trials included 275 randomized patients, 141 of whom received active treatment. One study examined cervical zygapophyseal joint pain, two cervicobrachial pain, three lumbar zygapophyseal joint pain, and one discogenic low-back pain. The study sample sizes were small, follow-up times short, and there were some deficiencies in patient selection, outcome assessments, and statistical analyses. The level of scientific evidence for the short-term effectiveness of radiofrequency denervation was limited for cervical zygapophyseal joint and cervicobrachial pain, and conflicting for lumbar zygapophyseal joint pain. There was limited evidence suggesting that intradiscal radiofrequency thermocoagulation was not effective for discogenic low-back pain. REVIEWER'S CONCLUSIONS: The selected trials provide limited evidence that radiofrequency denervation offers short-term relief for chronic neck pain of zygapophyseal joint origin and for chronic cervicobrachial pain; conflicting evidence on the short-term effect of radiofrequency lesioning on pain and disability in chronic low-back pain of zygapophyseal joint origin; and limited evidence that intradiscal radiofrequency thermocoagulation is not effective for chronic discogenic low-back pain. There is a need for further high-quality RCTs with larger patient samples and data on long-term effects, for which current evidence is inconclusive. Furthermore, RCTs are needed in non-spinal indications where radiofrequency denervation is currently used without any scientific evidence.

Comparison of the prevalence of inflammatory cells in subtypes of disc herniations and associations with straight leg raising.

STUDY DESIGN: The prevalence of inflammatory cells in 205 disc herniations (DHs) and nine macroscopically normal discs for comparison was studied immunohistochemically. Inflammatory cells were separately analyzed in subtypes of DH. Immunohistochemical data were related to clinical parameters, the straight leg raising test (SLR) in particular. OBJECTIVES: The objectives of the study were to compare the occurrence of inflammatory cells in various subtypes of DH and to determine the association between clinical data and inflammatory cell occurrence in a more extensive sample of DH, with separate analysis of DH subtypes. SUMMARY OF BACKGROUND DATA: Previous studies have suggested a common occurrence of inflammation and inflammatory cells, particularly macrophages, in DHs. No studies on any larger material comprising different subtypes of DH have been done. METHODS: For immunohistochemistry the alkaline phosphatase antialkaline phosphatase method was used. Monoclonal antibodies to T cells in general (CD2), activated T cells (CD25), B cells (CD22), and macrophages (CD68) were used. Obtained immunostaining results were then compared with clinical data, e.g., duration of pain, SLR, and type of DH (sequesters 86, extrusions 103, protrusions 16). Associations were studied by the chi2 test or Fisher's exact test, as applicable (level of significance P < 0.05). RESULTS: Abundant T cells were seen in 17% of the 205 DHs, activated T cells in 17%, B cells in 16%, and macrophages in 37%. All cell types were 2-3 times more prevalent in sequestrated discs than in extrusions. In protrusions macrophages were abundantly seen in 25% (4 of 16) and no other inflammatory cells. In patients with positive SLR and a sequestrated disc abundant lymphocytes were seen three times more often than in extrusions. When patients with bilaterally negative SLR were compared with those with tight SLR (< or =30 degrees ) with respect to inflammatory cell occurrence, some significant differences were noted (CD68, P < 0.025; CD25, P = 0.04). A comparison between SLR bilaterally positive and bilaterally negative also showed associations for all four inflammatory cell types (P = 0.016 to P = 0.029). There was no correlation between inflammatory cells and duration of pain. Abundant inflammatory cells were never seen in control discs. CONCLUSIONS: When SLR was positive and the DH type was sequestered, inflammatory cells were most commonly seen. Our results showed some statistically significant associations between inflammatory cells and SLR, most clearly when comparing bilaterally positive and negative SLR. Interestingly, a bilaterally positive SLR showed an association with all four inflammatory cell types analyzed. Tight SLR also showed an association, particularly with macrophages. In addition to tissue resorption, they may participate in sciatic pain. Even though lymphocytes were less prevalent, they may have some role in sequestered discs and bilaterally positive SLR.

Transforming growth factor beta receptor induction in herniated intervertebral disc tissue: an immunohistochemical study.

Transforming growth factor beta (TGF-beta) is a potent inducer of angiogenesis and fibrogenesis. There is presently little information about the pathophysiological function of TGF-beta in herniated disc tissue. In order to analyze the cellular role and activation of TGF-beta after disc herniation we immunostained frozen material from 38 disc herniation operations and from eight macroscopically normal discs from organ donors. Polyclonal TGF-beta-I, TGF-beta-II and TGF-beta receptor type II antibodies were used with the avidin biotin complex (ABC-) immunoperoxidase method. All the herniated discs were TGF-beta immunopositive. Such immunoreactivity was mainly associated with disc cells. In a few samples, capillaries were also TGF-beta immunopositive. Immunopositivity was similarly observed in the control discs. To analyze possible differences between the two groups, we calculated the ratio of immunopositive disc cells. For all three antibodies, a statistically significantly (Mann-Whitney test, P = 0.0001) higher number of disc cells showed immunopositivity in the herniated discs. The increase in TGF-beta receptor immunopositivity suggested induction of TGF-beta receptors in herniated discs. Our results support an active regulatory role for TGF-beta in disc cell metabolism.

Surgery vs orthosis vs watchful waiting for hallux valgus: a randomized controlled trial.

CONTEXT: Hallux valgus is a common foot deformation in adults, but evidence for effectiveness of surgical and conservative treatments for this condition is limited. OBJECTIVE: To compare the effectiveness of surgical and orthotic treatment with no treatment in patients with hallux valgus. DESIGN AND SETTING: Randomized controlled trial conducted in 4 general community hospitals in Finland in 1997-1998, with a follow-up period of 12 months. PARTICIPANTS: Two hundred nine consecutive patients (mean age, 48 years; 93% women) with a painful bunion and a hallux valgus angle 35 degrees or less. INTERVENTIONS: Patients were randomly assigned to surgery (distal chevron osteotomy; n = 71), orthosis (n = 69), or a 1-year waiting list (control group, n = 69). MAIN OUTCOME MEASURES: Pain intensity during walking on a visual analog scale (0-100), patient assessment of global improvement, number of painful days, cosmetic disturbance, footwear problems, functional status, and treatment satisfaction, compared among treatment groups. RESULTS: Follow-up rates at 6 and 12 months were 99% and 98%, respectively. At 6 months, pain intensity decreased more in the surgical group than in the control group (adjusted mean differences, -20 [95% confidence interval (CI), -28 to -12]) and more in orthosis than in the control groups (adjusted mean difference, -14 [95% CI, -22 to -6. At 1 year, pain intensity decreased more in the surgical than in the control groups (adjusted mean difference, -19 [95% CI, -28 to -10]) and more than in the surgical and orthosis groups (adjusted mean difference, -14 [95% CI, -22 to -5]). At 1 year, 83%, 46%, and 24% in the surgery, orthosis, and control groups, respectively, thought they had improved compared with baseline (number needed to treat), 1.7 between surgical and control groups). Number of painful days, cosmetic disturbance, and footwear problems were least and functional status and satisfaction with treatment were best in the surgical group. CONCLUSIONS: Surgical osteotomy is an effective treatment for painful hallux valgus. Orthoses provide short-term symptomatic relief.

Inflammatory cells, motor weakness, and straight leg raising in transligamentous disc herniations.

STUDY DESIGN: Possible statistically significant relationships between inflammatory cells and either motor weakness or straight leg raising were determined. OBJECTIVES: To look for any clinically relevant links between inflammatory cells in disc herniations and signs of radiculopathy. SUMMARY OF BACKGROUND DATA: Many studies have during recent years shown a presence of various types of inflammatory cells in disc herniations, but their clinical relevance has been questioned. To be clinically relevant, a presence of inflammatory cells should show a clear relationship to clinical evidence of nerve root involvement. Macrophages repeatedly demonstrated in a high proportion of disc herniations studied are of particular interest. Their major role may be in disc herniations tissue resorption and not in sciatica. METHODS: A total of 96 disc herniations, all transligamentous, were analyzed by immunohistochemistry for presence of macrophages, T or B lymphocytes, and activated T lymphocytes separately. From recorded patient data, motor weakness and straight leg raising data were compared with a presence or absence of abundant (+ = at least 20 cells in a group) inflammatory cells. When not abundant, inflammatory cells were classified as "only few cells" (+) and grouped together with "no cells" (-). Patients with or without motor weakness were compared. Straight leg raising was compared for a positive (at <70 degrees ) or a negative test, and separately using the median as cut-off value. Groups were compared by chi-square analysis with the level of statistical significance set at P<0.05. RESULTS: None of the four inflammatory cell types showed any significant association with motor weakness. Nor was any association observed when comparing positive and negative straight leg raising. With the median (straight leg raising = 47.5 degrees ) as cut-off, only activated T cells showed a weak (chi2 = 4.40, P<0.05) relationship with tighter straight leg raising, but none of the other cell types did. Even when straight leg raising was < 47.5 degrees, three times more disc herniations lacked (n = 34) inflammatory cells than showed (n = 13) inflammation. In a subgroup of only sequestrated discs, the findings were similar. However, in the patients with a bilaterally positive straight leg raising (n = 25), the prevalence of at least one inflammatory cell type was much higher in sequestrated discs (80%) than in extrusions (33%). This may suggest more subtle interrelationships between type of disc herniation, straight leg raising, and inflammatory cells. CONCLUSIONS: The results of this study do not support a clinically relevant role for disc herniation inflammatory cells in sciatica. For the cells to be clinically relevant, a strong relationship between a presence of inflammatory cells and either or both of motor weakness and a tight straight leg raising should have been observed. The authors conclude that macrophages, which have been demonstrated in a high proportion of disc herniations in previous studies, are probably more important for disc tissue resorption processes than for producing sciatica. Other types of inflammatory cells are more rarely observed and may have no clinical meaning at all. However, more subtle interrelationships, considering the various types of disc herniations, should be further explored.

Reoperations after lumbar disc surgery: a population-based study of regional and interspecialty variations.

STUDY DESIGN: A follow-up study using nationwide administrative databases. OBJECTIVES: To explore rates of reoperation after lumbar disc surgery and their regional and interspecialty variations. SUMMARY OF BACKGROUND DATA: In many Western countries, rates of lumbar disc surgery display significant geographic variations suggesting varying treatment criteria among operating surgeons. Few population-based studies have explored the risk of reoperation after disc surgery, and regional or interspecialty variations in the reoperations are unknown. METHODS: Patients who underwent lumbar spine surgery from January 1, 1987 through December 31, 1995, were identified in the Finnish Hospital Discharge Register. Data on the patients' initial disc operations, subsequent operations, and cause-of-death records were linked using personal identification codes. The Kaplan-Meier method and proportional hazard model were used to analyze risks of reoperation after initial surgery, according to hospital catchment area rates of disc surgery and for neurosurgical and orthopedic patients of university hospitals. RESULTS: 12.3% of 25,359 surgical patients with herniated lumbar discs underwent subsequent lumbar operations corresponding to the cumulative risk of 18.9% in the 9-year follow-up. Reoperation rates increased during the study period with the recent patient cohorts exhibiting risks. The reoperation risk showed a systematic geographic variation: the higher the regional disc surgery rate, the higher the reoperation risk. Overall, neurosurgical patients had a higher reoperation risk than orthopedic patients (relative risk [RR]: 1.57, 95% confidence interval [CI]: 1.17-2.10), but this was not a uniform finding. CONCLUSIONS: The reoperation risk after disc surgery increased during the study period and was higher in hospital catchment areas with higher overall discectomy rates. The reoperation risks varied among the university hospitals but tended to be higher for neurosurgical rather than for orthopedic patients.

The role of mast cells in disc herniation inflammation.

STUDY DESIGN: A study of herniated lumbar disc tissue samples and control disc material to determine the presence of mast cells in disc herniations. OBJECTIVES: To analyze whether mast cells have any involvement in disc herniation pathophysiology and lumbar pain, because mast cells may have an important role in acute and chronic inflammatory responses. SUMMARY OF BACKGROUND DATA: Studies of inflammatory cells, biochemical mediators of inflammation, and tissue degrading enzymes have suggested that these factors may be involved--and perhaps play an important role--in the pathophysiology of lumbar pain and radiculopathy. Mast cells are known to play an important role in acute and chronic inflammatory responses. It was therefore of interest to clarify their possible role in intervertebral disc herniation inflammation. METHODS: Fifty herniated lumbar discs from 50 patients who had undergone disc surgery and three normal control discs were obtained. Sections from every disc then were examined histologically and immunocytochemically for mast cells by using monoclonal antibodies to either of two types of specific proteases of mast cells, tryptase and chymase. RESULTS: By none of the methods could any mast cells be observed in any of the control disc samples. With toluidine blue staining, mast cells were observed in 9 of 50 (18%) of discs. Mast cells immunoreactive to either tryptase or chymase were observed in 10 of 50 disc samples (20%) and immunoreactive for tryptase and chymase simultaneously in 4 of 50 disc samples (8%). However, the majority of the samples studied (80%) demonstrated immunoreactivity to neither tryptase nor chymase. Among the samples studied were five disc protrusions that totally lacked mast cells. CONCLUSIONS: A minority of disc herniations exhibited mast cells, as verified by toluidine blue staining and immunocytochemistry. The results may suggest a role of mast cells in intervertebral disc herniation inflammation, but only in a subset of these cases. Massive infiltration by mast cells never was observed.

A comparative immunohistochemical study of inflammatory cells in acute-stage and chronic-stage disc herniations.

STUDY DESIGN: Herniated lumbar disc specimens were obtained from patients undergoing surgical discectomy for persistent radicular pain (radiculopathy) and stained for inflammatory cells to determine their occurrence in relation to the duration of radicular pain and to analyze the role of the time factor in the inflammatory response. OBJECTIVES: To analyze the presence of inflammatory cells and their involvement in the pathophysiology of radicular pain and to determine whether there is a clear difference in the occurrence of inflammatory cells between the earlier phase of radicular pain (after herniation) and the later chronic stage. SUMMARY OF BACKGROUND DATA: Previously, inflammatory cells were reported in herniated disc tissues, and macrophages were most prevalent. Biologically active inflammatory mediators have also been repeatedly observed. However, there have been no observations regarding possible differences in the occurrence of inflammatory cells in radicular pain of different durations. METHODS: Forty-four herniated lumbar discs were obtained from 44 patients undergoing disc surgery. Two groups of 22 age- and gender-matched patients with comparable affected disc levels were studied. In the first group (acute group) pain duration ranged from 3 days to 21 days. In the second group (chronic group) pain duration was 6 months or longer. All disc herniation specimens were subjected to indirect immunocytochemistry to study and compare the presence of inflammatory cells. RESULTS: Inflammatory cells, predominantly macrophages, were observed in both groups. Macrophages were abundantly present in eight (36%) disc samples in the acute group; in three (14%) samples only few scattered macrophages were observed. In the chronic group, in nine (41%) disc samples, abundant macrophages were observed; in six (27%) there were a few scattered macrophages. In the acute group, in three (14%) disc samples abundant activated T lymphocytes were observed; in two (9%) there were only a few activated T lymphocytes, whereas in the chronic group abundant activated T lymphocytes were not seen; only a few scattered activated T lymphocytes were observed in five (23%) disc tissue samples. In two (9%) samples in the acute group, B cells were abundantly present, and in two (9%) only a few B cells were observed. In the chronic group, abundant B cells were seen in no samples, and only a few B cells were noted in one (5%) sample. Only in the acute group and only in lateral disc herniations were abundant lymphocytes observed. In disc samples from intraspinal herniations, acute and chronic, there were only abundant macrophages, not lymphocytes. CONCLUSIONS: Because of the small size of the study groups and the low prevalence particularly of lymphocytes in both groups, no major group differences were noted. The prevalence of macrophages was highest, similar in both groups, and was similar to the results in prior studies. The results indicate no major differences in the occurrence of inflammatory cells in acute and chronic disc herniations. They also indicate that only macrophages may have a clinical relevance in disc tissue inflammation.

Platelet-derived growth factor and vascular endothelial growth factor expression in disc herniation tissue: and immunohistochemical study.

Angiogenesis is essential in tissue growth and regeneration. There are several factors that are able to stimulate vascular endothelial cell growth, including platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF). Disc herniation tissue (DHT) contains vascular ingrowth, which promotes granulation tissue formation. In this study we observed 50 disc herniations for PDGF and VEGF immunoreactivity. PDGF immunopositivity was detected in 38 samples (78%). In 28 samples (56%) there were PDGF immunopositive capillaries, PDGF immunopositive disc cells were detected in 19 samples (38%) and PDGF immunopositive fibroblasts in 6 DHT samples (12%). VEGF immunopositive capillaries were identified in 44 DHT samples (88%). For neither growth factor was immunopositivity dependent on preoperative radicular pain duration. In extrusions (n = 25) VEGF immunopositive capillaries were detected in 23 samples (92%) and PDGF immunopositivity in 21 samples (84%). PDGF immunopositivity was more commonly associated with capillaries than with nuclei of disc cells. In sequesters (n = 20) VEGF immunopositive capillaries were identified in all samples and PDGF immunopositivity in 16 (80%). As in extrusions, PDGF immunoreaction was more prevalent in capillaries than in disc cells. Patient age did not relate to VEGF expression. In all age groups it was higher than 80%. Thus capillaries in disc herniation tissue are evidently newly formed and our results demonstrate that PDGF and VEGF participate in the neovascularization process. The presence of PDGF in fibroblasts and in disc cells suggests that this growth factor regulates the function of these cells, possibly the proliferation of the cells and the production of extracellular matrix components.

Disc degeneration in young patients with isthmic spondylolisthesis treated operatively or conservatively: a long-term follow-up.

The purpose of this long-term follow-up was (1) to investigate disc changes in the olisthetic segment in patients treated conservatively, (2) to compare disc changes above the slipped vertebra in conservatively treated patients with those in operatively treated patients, and (3) to establish possible relations of disc changes to the degree of the slip and to subjective back pain symptoms of the patients. The subjects were 227 patients with isthmic L5 olisthesis diagnosed under 20 years of age (mean 13.8 years) with a mean follow-up of 15.4 (range 5-30) years. Of these, 145 patients had been treated with segmental fusion and 82 had been treated conservatively. At follow-up, standing anteroposterior and lateral radiographs as well as flexion/extension views of the lumbar spine were taken. Disc degeneration was graded semiquantitatively: 0 = normal disc height, 1 = decrease of disc height < 50%, 2 = decrease > or = 50%, and 3 = obliteration of the disc. In the conservatively treated patients degeneration of the olisthetic disc was distributed by grade as follows: O: n = 38, 1: n = 24, 2: n = 14, 3: n = 6. No motion at all was observed in the olisthetic segment in 40 patients (48%) with a mean slip of 30%, segmental motion of 4 degrees-18 degrees was found in 42 patients with a mean slip of 14%. There was a statistically significant association of the degree of slip to the severity of disc degeneration and non-mobility of the segment. Grade 1 degeneration of the L4/5 disc occurred in 25.6% of the conservatively treated patients and in 32% of 48 patients treated with L5-S1 fusion. This correlated with the severity of the slip, but not with pain symptoms or pathologic segmental mobility at the time of follow-up. Out of 84 patients with L4-S1 fusion, in 17% grade 1 degeneration of the L3/4 disc was observed, and 3 out of 13 patients (23%) with L3-S1 fusion had grade 1 degeneration of the disc above the fusion. The disc changes had no correlation with subjective pain symptoms. It is concluded that the natural course of isthmic spondylolisthesis is associated with disc degeneration and spontaneous stabilization of the olisthetic segment. Fusion operations do not significantly increase the rate of disc degeneration in the adjacent disc above the fusion after a mean postoperative follow-up of 13.8 years. No correlation between the number of degenerated discs or the degree of degeneration and subjective low back pain symptoms was found.

A controlled biochemical and immunohistochemical study of human synovial-type (group II) phospholipase A2 and inflammatory cells in macroscopically normal, degenerated, and herniated human lumbar disc tissues.

STUDY DESIGN: Group II phospholipase A2 enzyme activity was studied biochemically and immunohistochemically in tissue samples from disc prolapses, degenerated discs, and macroscopically normal discs. In parallel, phospholipase A2 and inflammatory cells were studied by indirect immunocytochemistry. OBJECTIVES: To compare phospholipase A2 activity in normal discs and abnormal discs by an identical assay for phospholipases A2, and to compare the occurrence of inflammatory cells with phospholipase A2 activity and immunoreactivity. SUMMARY OF BACKGROUND DATA: It has been suggested that a high phospholipase A2 enzyme activity in herniated disc tissue could be significant in abnormal states such as sciatica and discogenic pain. No comparison between healthy disc tissue and samples of abnormal discs (degenerated or herniated) has been carried out. In particular, an identical assay for phospholipase A2 for such tissue samples, supported by immunohistochemical staining data, has never been applied in parallel to normal and abnormal disc tissue, and neither have such results been compared with the demonstration of inflammatory cells. METHODS: Group II phospholipase A2 enzyme activity was determined, in parallel, using an identical assay for tissue samples from 11 macroscopically normal discs, 33 disc herniations, and six discs showing degeneration by discography. For determination of phospholipase A2 enzyme activity, a radioassay using 1-palmitoyl-2-(1-14C)linoleoyl-L-3-phosphatidylethanolamine as the phospholipid substrate was used. Total tissue DNA as an estimate of total tissue cell number was measured in parallel with phospholipase A2 activity. All tissue samples also were studied by indirect immunocytochemistry, locating phospholipase A2 and T and B lymphocytes. RESULTS: Neither degenerated nor herniated disc tissue samples demonstrated a higher phospholipase A2 activity than control disc tissue samples. Average phospholipase A2 activity was actually higher in the control samples than in herniated disc samples (Mann-Whitney test, P < 0.001), possibly a result of a higher total DNA (P < 0.005). The observed level of phospholipase A2 activity was lower than that of inflammatory human synovial fluid. Neither was there marked immunoreactivity for phospholipase A2, which was observed in chondrocytes in areas of cartilage and occasional disc cells, supporting the biochemical results. Lymphocytes were more numerous only in herniated disc samples (15%), and their presence showed little overlap with phospholipase A2 immunoreactivity. CONCLUSIONS: Synovial-type (Group II) phospholipase A2 enzyme activity is not particularly high in disc tissue and does not appear to be higher in herniated or degenerated discs than control disc tissue. Immunoreactivity to phospholipase A2 is seen only occasionally and is strong only when cartilage tissue is present. Neither are inflammatory lymphocytes commonly observed.