Distraction arthrodesis of the sacroiliac joint: 2-year results of a descriptive prospective multi-center cohort study in 171 patients
Fuchs, V. & Ruhl, B. Eur Spine J (2018) 27: 194.
https://doi.org/10.1007/s00586-017-5313-2
Abstract
Purpose
The aim of the given study was to evaluate the long-term outcomes of patients undergoing sacroiliac joint (SIJ) distraction arthrodesis to treat SIJ-related pain.
Methods
Descriptive prospective multi-center cohort study involving 20 hospitals in Germany. Between January 2011 and June 2012, 171 patients with chronic SIJ pain underwent indirect arthrodesis of the SIJ using a distraction implant. The patients were questioned prior to surgery, 6-weeks, and 3-, 6-, 12- and 24-months postoperatively. Overall patient satisfaction was surveyed along with pain medication intake, the Million Visual Analogue Scale (MVAS), Oswestry Disability Index (ODI), Short-form McGill Pain Questionnaire (SF-MPQ), 12-Item Short-Form Health Survey (SF-12), Visual Analogue Scale (VAS) and a pain drawing. Bony fusion of the SIJ was evaluated using X-ray and computed tomography (CT).
Results
A majority of patients (73%) reported to feel better or much better 24 months post-surgery, 49% of the patients reduced their pain medication intake. The MVAS dropped from 63 to 36%, the ODI improved from 51 to 33%, the SF-MPQ decreased from 50 to 31%, the SF-12 physical component summary rose from 22 to 41%, the mental component summary increased from 40 to 55%, and pain as measured by the VAS decreased from 74 to 37 points (all comparisons p < 0.001). In the follow-up CT scans 31% of the patients showed SIJ fusion.
Conclusions
SIJ distraction arthrodesis has shown satisfactory outcomes in patients with SIJ-related pain for all scores reported in the surveys, accompanied by increased functionality.
Keywords
Sacroiliac joint fusion Sacroiliac joint arthrodesis DIANA implant Distraction interference arthrodesis with neurovascular anticipation Pain drawing
Introduction
Lower lumbar and lumbosacral pain originating from the sacroiliac joint (SIJ) rather than from the lumbar spine has been described in the context of outpatient care with incidences of 13–30% [1, 2, 3, 4, 5, 6]. It has been reported that the incidence of SIJ-triggered pain increases up to 32–43% as a consequence of lumbar spinal fusion, in particular including the L5–S1 segment [7, 8, 9, 10]. Despite a range of adequate conservative treatment options, a certain percentage of patients continue to have a considerably reduced quality of life due to persistent SIJ pain [6]. These patients’ pain symptoms are comparable to those with other musculoskeletal disorders, such as spinal canal stenosis and osteoarthritis of the hip joint [11, 12].
As a consequence of the lack of limited-open and low-complication surgical techniques to the SIJ, patients with SIJ-related pain are often referred to pain therapy as a final treatment option.
In late 2009, a new surgical procedure for the fusion of the painful SIJ was introduced in Germany, the so-called distraction interference arthrodesis with neurovascular anticipation (DIANA®, SIGNUS Medizintechnik GmbH, Germany). The initial outcomes of this were promising, leading to the decision to set up a multi-center observational study. The given study aimed to quantify if patients in a large multi-center cohort with chronic SIJ pain benefitted from SIJ arthrodesis under distraction over a 24-month observation period. The second aim was to analyze if participants with a typical preoperative pain pattern of the SIJ had a different outcome than those patients with an atypical pain distribution.
Materials and methods
Study design
Patients with chronic SIJ pain were included from 20 German hospitals in this descriptive prospective multi-center cohort study, with pain persisting for 6 months or more. Only patients with exhausted options of conservative treatment (≥ 6 months) were included, such as physiotherapy, manual therapy, therapeutic ultrasound, SIJ orthoses, peri- and intra-articular infiltration and SIJ denervation. The inclusion period was from January 2011 to June 2012. The study design was questionnaire based, surveying on preoperative and postoperative data at 6 weeks and 3, 6, 12 and 24 months. The patients themselves completed all postoperative questionnaires free from external influence at home. Besides magnetic resonance imaging (MRI) and X-rays of the lumbar spine preoperative imaging diagnostics included X-ray and computed tomography (CT) scans of the pelvis. A corresponding imaging of the pelvis was scheduled to be obtained immediately following the surgery and in a 6-month follow-up. The exclusion criteria included the presence of a tumor or bacterial infection, multiple prior surgical procedures to the SIJ, sacral insufficiency fractures and bony defects in the area of the recess of the ilium and sacrum following bone graft harvesting. Patients with ongoing pension claims or on disability leave were also excluded. Preoperative RF neurotomy was no precondition for the patients to be included in our study. No age-related exclusion criteria were defined. All relevant ethics committees approved the study. All patients gave their informed and written consent.
Indication for surgery
Severe arthritis of both accessory joints between S2 transverse process of the sacrum and ilium
However, it was not mandatory for all of the above-mentioned criteria to be fulfilled completely to enroll eligible patients in this study. The decision was made by the surgeon on basis of a conclusive combination of medical history, clinical tests, SIJ injections, X-ray and CT scan.
Rationale and surgical technique
a Severe arthritis of both SIJs with subluxation. b CT scan of the same patient 20 months postoperatively showing complete reposition and fusion
DIANA implant located in the recess of the SIJ between sacrum and ilium; the cartilaginous part of the SIJ is almost not addressed with the implant
(modified picture of Schuenke et al. Thieme Atlas of Anatomy, General Anatomy Musculoskeletal System, pp. 116–117; © Thieme 2007)
Fluoroscopic views of correct intraoperative implant position. a a.p. view, b oblique view, c lateral view
a Preoperative X-ray of severe left SIJ arthritis. b Postoperative X-ray with DIANA implant and distraction of left SIJ
Follow-up treatment
Post-surgery the patients were mobilized for 6–8 weeks with a partial weight bearing (20 kg) on the operated side not to lose the achieved intraoperative distraction and ligamentotaxis. Vitamin D supplement therapy was carried out for 3 months postoperatively to promote bone metabolism [22, 23]. Patients undergoing surgery of both SIJs underwent two separate procedures. However, the second side was not operated on until full bearing was achieved on the side operated first.
Outcome measures
Preoperative data collection took place at the respective hospital of surgery. The postoperative surveys were mailed to the participants and completed by the patients independently. The questionnaires included: Million Visual Analogue Scale (MVAS), Oswestry Disability Index (ODI), Short-form McGill Pain Questionnaire (SF-MPQ), 12-Item Short-Form Health Survey (SF-12), and a pain drawing (PD). The postoperative questionnaires also contained questions about patient satisfaction.
a Typical pain drawing. b Untypical pain drawing
a Preoperative vacuum phenomenon left and right SIJ. b Postoperative distraction and subsidence of vacuum phenomenon right SIJ (S1-pedicle screw removed)
Statistical analysis
Group comparisons were performed using the Mann–Whitney U test, Wilcoxon signed-ranks test, Chi-square test and McNemar test. For multiple testing, confidence levels were adjusted using the Holm–Bonferroni-method. All calculations and visualizations were implemented in the Python programming language using community managed open source libraries of scientific tools (NumPy, SciPy, StatsModels, pandas, Matplotlib). For the scoring of the 12-Item Short-Form Survey (SF12), physical and mental component summaries (PCS/MCS) were calculated by reversing items 1, 8, 9, and 10. Scores were then calculated as a percentage ranging from the minimal (0%) to the maximal (100%) possible sum of all items (PCS: items 1–5 and 8; MCS: remaining items). Patients treated on both sides were considered as independent data sets regarding each operation.
Results
Patient numbers and operations
Preoperative questionnaires were received from a total of 171 patients. An operation of the contralateral SIJ was performed in 7 patients (4.1%) in the 24-month surveillance period. At the study endpoint (24 months post-surgery), 143 12-month datasets from 137 patients and 137 24-month datasets from 132 patients were available for evaluation (22.8% loss to follow-up at 24 months). Revisions due to misplacements of the implant or persistent pain were reported in six patients (4.3%) in the postoperative course. All of these patients were followed-up after revision surgery for a period of 12–24 months and were included in the evaluation.
Demographic and surgery-related data
Characteristics of enrolled subjects (missing percentages = no response)
Characteristics |
Value |
---|---|
Subjects (female) |
67% |
Age females, mean (range) |
54 (21–82) |
Age males, mean (range) |
53 (28–78) |
Years of pain, mean |
4.5 |
Prior lumbar operation |
45% |
Pedicle screw L5/S1 |
27% |
Work status at the time of operation |
|
Unable to work |
31% |
Pension |
35% |
Working |
32% |
Prior conservative treatment |
|
Physiotherapy |
87% |
Manual therapy |
66% |
Denervation |
37% |
Orthosis |
12% |
Clinical outcomes
MVAS preoperatively, 12 and 24 months postoperatively (all p values < 0.001)
ODI preoperatively, 12 and 24 months postoperatively (all p values < 0.001)
Outcomes at baseline and after surgery (12 and 24 months); difference = 24 months − baseline value
Baseline |
12 months |
24 months |
Difference |
p value |
|
---|---|---|---|---|---|
Mean (SD) |
Mean (SD) |
Mean (SD) |
|||
MVAS |
63 (26) |
38 (29) |
36 (30) |
− 27 |
p < 0.001 |
ODI |
51 (26) |
35 (27) |
33 (28) |
− 18 |
p < 0.001 |
SF-MPQ |
50 (16) |
33 (23) |
31 (25) |
− 19 |
p < 0.001 |
VAS total |
74 (20) |
39 (29) |
37 (30) |
− 37 |
p < 0.001 |
VAS leg |
60 (27) |
33 (29) |
32 (30) |
− 28 |
p < 0.001 |
SF-12 (PCS) |
22 (15) |
40 (26) |
41 (27) |
19 |
p < 0.001 |
SF-12 (MCS) |
40 (20) |
54 (24) |
55 (25) |
15 |
p < 0.001 |
VAS preoperatively, 12 and 24 months postoperatively (all p values < 0.001)
Patient satisfaction
When asked about their current level of satisfaction, 73.3% of all patients reported that they felt better or much better 24 months postoperatively than prior to surgery. In contrast, 13.7 and 13.0% of the patients reported that they felt the same or worse. After 12 months, 79.0% of the participants responded ‘yes’ to the question as to whether they would recommend the surgical method to a good friend and 78.5% responded with ‘yes’ after 24 months.
Pain drawing
Outcomes in patients with typical pain drawing vs. patients with atypical pain drawing at baseline and 24 months after surgery; difference = 24 months − baseline value
Baseline |
24 months |
Difference |
p value |
|
---|---|---|---|---|
Mean (SD) |
Mean (SD) |
|||
Typical PD |
||||
MVAS |
63 (14) |
28 (24) |
−35 |
p < 0.001 |
ODI |
51 (14) |
27 (20) |
−24 |
p < 0.001 |
SF-MPQ |
49 (16) |
23 (22) |
−26 |
p < 0.001 |
VAS |
73 (19) |
29 (28) |
−44 |
p < 0.001 |
Atypical PD |
||||
MVAS |
63 (16) |
46 (25) |
−17 |
p < 0.001 |
ODI |
51 (16) |
40 (19) |
−11 |
p < 0.001 |
SF-MPQ |
48 (17) |
38 (24) |
−10 |
p = 0.011 |
VAS |
75 (18) |
48 (29) |
−27 |
p < 0.001 |
Analgesic use
Individual level change (24 months − preoperative) within the groups of analgesics (strong opioid, weak opioid, non-opioid, on-demand medication, no analgesic)
Imaging
A complete series of CT scans (pre-/postoperatively/6 months or more) was available for 115 operations. The radiologists’ assessments on fusion and vacuum phenomena diverged in four of the cases (3.5%). 36 operations (31.3%) were assessed as unequivocally fused, with a considerably higher fusion rate of 67% when BMP-2 was used compared to a fusion rate of 19% when no BMP-2 was used (p < 0.001). In terms of operations with no observed vacuum phenomenon (preoperative vacuum phenomenon in SIJ space, no longer present in the last follow-up CT), the fusion rate amounted to 83% in contrast to a fusion rate of 13% for operations showing a vacuum phenomenon (p < 0.001). In 33% of the cases a poor implant position (implant inserted too far into the ilium or the sacrum) was observed. Overdistraction of the SIJ as an indirect sign of a rupture of the surrounding sacroiliac ligaments was not found in any of the cases. Statistics showed no significant correlation regarding fusion against all scores (ODI, MVAS, SF-MPQ, VAS) or the reported improvements of back or leg pain by the patient.
Complications
Intraoperative and implant-associated postoperative complications occurred in one case, where a sensory L5-radiculitis was caused by too liberally applied bone substitute. After surgical revision and removal of the bone substitute, symptom relief was achieved in 5 days.
Discussion
This study is the first prospective multi-center study to report on 2-year findings after posterior SIJ arthrodesis using the DIANA technique in patients with SIJ-related pain.
Compared to the most common lateral transarticular approach [21], the DIANA SIJ fusion technique has several advantages. First, decortication of the ilium and sacrum, bone grafting and fixation follows orthopedic principals concerning bone to bone fusion. Laterally based techniques rely mostly on transfixation of the ilium against the sacrum. Second, distracting the ilium against the sacrum can achieve a reposition of a subluxated SIJ into anatomic position again. Lateral techniques might transfixate the SIJ in an unphysiological position. Third, using the recess for SIJ fusion is a safe approach because no major nerves or vessels are at risk. Lateral approaches might harm the superior gluteal neurovascular bundle or the S1 or S2 nerve root in case of a too deep implant positioning or narrow bony corridors in between the neuroforamen of the sacrum [28]. Fourth, the dorsal approach offers the opportunity to remove accessory joints in the recess of the SIJ. Lateral approaches are not able to address this pathology directly. Finally, in case of a pseudarthrosis the distraction implant is easy to revise through the same approach going again for decortication, grafting and fixation with a larger implant. Lateral-based implants coming loose in the soft bone of the sacrum but being well integrated in the ilium or vice versa might be hard to remove without collateral damage.
The preoperative quality of life of the patients included in the given study was as strongly compromised, comparable to patients with lumbar spine pathology [12]. Although patients suffered from pain for 4.5 years on average, had exhausted the options for conservative treatment and in many cases already undergone spinal surgery, the study outcomes showed a clear and sustainable decrease in SIJ-related pain in a 2-year interval. The vast pain decrease is also reflected by the overall decrease in the use of pain medication. In those patients who reported an increase in the need for analgesics 24 months after the operation, only 13.6% reported that they felt worse than before surgery. Because of those findings, we can only speculate that the higher demand of analgesics in most of those patients might be due to a different reason than ongoing SIJ pain.
Comparison of study results Fuchs et al. and Sturesson et al.
Follow-up (months) |
VAS |
ODI |
Procedure again (%) |
|
---|---|---|---|---|
Fuchs et al. (DIANA) |
24 |
37 |
33 |
78 |
Sturesson et al. (iFuse) |
6 |
34 |
32 |
80 |
a Insufficient preparation and bone apposition in the recess around the implant. b Inadequate position of the implant (in the example shown here, too far inside the ilium). c Solid fusion of the SIJ
The positive aspects of the given study include that it is a prospective multi-center study independent of the initial describer of the procedure [21]. Furthermore, all of the patients were able to complete their postoperative questionnaires at any time without any influence by third parties.
This study, however, has a few limitations. Most importantly, a corresponding conservative control group is missing. This concept was discarded for two reasons: First, it was difficult to standardize a corresponding control group at the given level of quality. Second, the participants were for the most part, patients who had exhausted all options for conservative treatment and at the time of the study were hoping to solve their problem as a result of the surgery. Furthermore, the data presented were certainly negatively influenced by the large number of patients who already undergone previous surgery and chronic pain patients who had pain for many years in various parts of their body. Moreover, among the participating physicians, due to the nature of the surgical technique, there was a certain level of uncertainty with regard to their indications of the procedure. Also, the learning curve for the novices needs to be acknowledged, which for most of the surgeons was included in the results presented here in nearly its entirety.
Conclusion
This prospective multi-center study demonstrated that patients with long-lasting and severe SIJ pain, that were treated with distraction arthrodesis of the SIJ, had reduced pain and disability and increased quality of life after 24 months. The absence of permanent nerve and vascular injuries is evidence that distraction arthrodesis is a safe and gentle surgical procedure.
Notes
Acknowledgements
The authors acknowledge the 20 investigators of the surveillance study (alphabetical order): M Alquiza (Berlin), M Breitenfelder (Ludwigshafen), U Bürgel (Kleve), H Dast (Stuttgart), U Dott (Köln), S Endres (Olsberg), J Gulow (Leipzig), F Hassel (Freiburg), B Hölper (Gelnhausen), R Kayser (Greifswald), D Klase (Hamburg), J Lang (Erwitte), U Laupichler (Schwandorf), P Madjurow (Berlin), J Mechler (Tönning/Husum), P Militzer (Heidelberg), J Nothwang (Schorndorf), M Schaefer (Würzburg), J-U Völzer (Kyritz). The authors also would like to thank T Kibsgård, N Hammer and J Haenicke for their professional support.
Compliance with ethical standards
Conflict of interest
Volker Fuchs is a primary investigator in SIGNUS clinical trials. He is a paid consultant of SIGNUS. The surveillance study was funded by SIGNUS Medizintechnik GmbH.
References
-
1.Bernard TN, Kirkaldy-Willis WH (1987) Recognizing specific characteristics of nonspecific low back pain. Clin Orthop Relat Res 217:266–280Google Scholar
-
2.Schwarzer AC, Aprill CN, Bogduk N (1995) The sacroiliac joint in chronic low back pain. Spine (Phila Pa 1976) 20:31–37CrossRefGoogle Scholar
-
3.Maigne JY, Aivaliklis A, Pfefer F (1996) Results of sacroiliac joint double block and value of sacroiliac pain provocation tests in 54 patients with low back pain. Spine (Phila Pa 1976) 21:1889–1892CrossRefGoogle Scholar
-
4.Irwin RW, Watson T, Minick RP, Ambrosius WT (2007) Age, body mass index, and gender differences in sacroiliac joint pathology. Am J Phys Med Rehabil 86:37–44CrossRefPubMedGoogle Scholar
-
5.Vleeming A, Albert HB, Ostgaard HC, Sturesson B, Stuge B (2008) European guidelines for the diagnosis and treatment of pelvic girdle pain. Eur Spine J 17:794–819CrossRefPubMedPubMedCentralGoogle Scholar
-
6.Sembrano JN, Polly DW (2009) How often is low back pain not coming from the back? Spine 34:E27–E32CrossRefPubMedGoogle Scholar
-
7.Katz V, Schofferman J, Reynolds J (2003) The sacroiliac joint: a potential cause of pain after lumbar fusion to the sacrum. J Spinal Disord Tech 16:96–99CrossRefPubMedGoogle Scholar
-
8.Maigne JY, Planchon CA (2005) Sacroiliac joint pain after lumbar fusion. A study with anesthetic blocks. Eur Spine J 14:654–658CrossRefPubMedPubMedCentralGoogle Scholar
-
9.Depalma MJ, Ketchum JM, Saullo TR (2011) Etiology of chronic low back pain in patients having undergone lumbar fusion. Pain Med 12:732–739CrossRefPubMedGoogle Scholar
-
10.Liliang PC, Lu K, Liang CL, Tsai YD, Wang KW, Chen HJ (2011) Sacroiliac joint pain after lumbar and lumbosacral fusion: findings using dual sacroiliac joint blocks. Pain Med 12:565–570CrossRefPubMedGoogle Scholar
-
11.Cher DJ, Polly D, Berven S (2014) Sacroiliac joint pain: burden of disease. Med Devices (Auckl) 7:73–81Google Scholar
-
12.Cher DJ, Reckling WC (2015) Quality of life in preoperative patients with sacroiliac joint dysfunction is at least as depressed as in other lumbar spinal conditions. Med Devices (Auckl) 8:395–403Google Scholar
-
13.Laslett M, Aprill CN, McDonald B, Young SB (2005) Diagnosis of sacroiliac joint pain: validity of individual provocation tests and composites of tests. Man Ther 10:207–218CrossRefPubMedGoogle Scholar
-
14.Van der Wurff P, Buijs EJ, Groen GJ (2006) A multitest regimen of pain provocation tests as an aid to reduce unnecessary minimally invasive sacroiliac joint procedures. Arch Phys Med Rehabil 87:10–14CrossRefPubMedGoogle Scholar
-
15.Fortin JD, Ballard KE (2009) The frequency of accessory sacroiliac joints. Clin Anat 22:876–877CrossRefPubMedGoogle Scholar
-
16.Prassopoulos PK, Faflia CP, Voloudaki AE, Gourtsoyiannis NC (1999) Sacroiliac joints: anatomical variants on CT. J Comput Assist Tomogr 23:323–327CrossRefPubMedGoogle Scholar
-
17.Snijders CJ, Vleeming A, Stoeckart R (1993) Transfer of lumbosacral load to iliac bones and legs. Part 1: biomechanics of self-bracing of the sacroiliac joints and its significance for treatment and exercise. Clin Biomech 8:285–294CrossRefGoogle Scholar
-
18.Vleeming A, Buyruk HM, Stoeckart R, Karamursel S, Snijders CJ (1992) An integrated therapy for peripartum pelvic instability: a study of the biomechanical effects of pelvic belts. Am J Obstet Gynecol 166:1243–1247CrossRefPubMedGoogle Scholar
-
19.Damen L, Spoor CW, Snijders CJ, Stam HJ (2002) Does a pelvic belt influence sacroiliac joint laxity? Clin Biomech (Bristol, Avon) 17:495–498CrossRefGoogle Scholar
-
20.Mens JMA, Damen L, Snijders CJ, Stam HJ (2006) The mechanical effect of a pelvic belt in patients with pregnancy-related pelvic pain. Clin Biomech (Bristol, Avon) 21:122–127CrossRefGoogle Scholar
-
21.Stark JG, Fuentes JA, Fuentes TI, Idemmili C (2011) The history of sacroiliac joint arthrodesis: a critical review and introduction of a new technique. Curr Orthop Pract 22:545–557CrossRefGoogle Scholar
-
22.Kerezoudis P et al (2016) Association between vitamin D deficiency and outcomes following spinal fusion surgery: a systematic review. World Neurosurg 95:71–76CrossRefPubMedGoogle Scholar
-
23.Metzger MF, Kanim LE, Zhao L, Robinson ST, Delamarter RB (2015) The relationship between serum vitamin D levels and spinal fusion success: a quantitative analysis. Spine 40(8):E458–E468CrossRefPubMedPubMedCentralGoogle Scholar
-
24.Fortin JD, Aprill CN, Ponthieux B, Pier J (1994) Sacroiliac joint: pain referral maps upon applying a new injection/arthrography technique. Part II: clinical evaluation. Spine (Phila Pa 1976) 19:1483–1489CrossRefGoogle Scholar
-
25.Van Der Wurff P, Buijs EJ, Groen GJ (2006) Intensity mapping of pain referral areas in sacroiliac joint pain patients. J Manipulative Physiol Ther 29:190–195CrossRefPubMedGoogle Scholar
-
26.Fortin JD, Vilensky JA, Merkel GJ (2003) Can the sacroiliac joint cause sciatica? Pain Physician 6:269–271PubMedGoogle Scholar
-
27.Kurosawa D, Murakami E, Aizawa T (2015) Referred pain location depends on the affected section of the sacroiliac joint. Eur Spine J 24:521–527CrossRefPubMedGoogle Scholar
-
28.Collinge C, Coons D, Aschenbrenner J (2005) Risks to the superior gluteal neurovascular bundle during percutaneous iliosacral screw insertion: an anatomical cadaver study. J Orthop Trauma 19:96–101CrossRefPubMedGoogle Scholar
-
29.Copay AG, Glassman SD, Subach BR, Berven S, Schuler TC, Carreon LY (2008) Minimum clinically important difference in lumbar spine surgery patients: a choice of methods using the Oswestry Disability Index, Medical Outcomes Study questionnaire ShortForm 36 and pain scales. Spine J 8(6):968–974CrossRefPubMedGoogle Scholar
-
30.Childs JD, Piva SR, Fritz JM (2005) Responsiveness of the numeric pain rating scale in patients with low back pain. Spine 30(11):1331–1334CrossRefPubMedGoogle Scholar
-
31.Parker SL, McGirt MJ (2015) Determination of the minimum improvement in pain, disability, and health state associated with cost-effectiveness: introduction of the concept of minimum cost-effective difference. Neurosurgery 76(Suppl 1):64–70CrossRefGoogle Scholar
-
32.Parker SL, Mendenhall SK, Shau D et al (2012) Determination of minimum clinically important difference in pain, disability, and quality of life after extension of fusion for adjacent-segment disease. J Neurosurg Spine 16(1):61–67CrossRefPubMedGoogle Scholar
-
33.Parker SL, Mendenhall SK, Shau DN et al (2012) Minimum clinically important difference in pain, disability, and quality of life after neural decompression and fusion for same-level recurrent lumbar stenosis: understanding clinical versus statistical significance. J Neurosurg Spine 16(5):471–478CrossRefPubMedGoogle Scholar
-
34.Sturesson B, Kools D, Pflugmacher R, Gasbarrini A, Prestamburgo D, Dengler J (2017) Six-month outcomes from a randomized controlled trial of minimally invasive SI joint fusion with triangular titanium implants vs conservative management. Eur Spine J 26:708–719CrossRefPubMedGoogle Scholar
-
35.Grafton KV, Foster NE, Wright CC (2005) Test-retest reliability of the Short-Form McGill Pain Questionnaire: assessment of intraclass correlation coefficients and limits of agreement in patients with osteoarthritis. Clin J Pain 21:73–82