Background. Neurogenic claudication is a well recognised symptom of spinal stenosis. Pain in the lower limbs and back limit walking speed and distance. Outcome of treatment should be easily measurable, but in practice is not. Walking tests are difficult to perform reliably. It is possible to measure speed and endurance with a treadmill, but this is expensive, of doubtful reliability, and many elderly patients are reasonably worried about falling off. Commonly used back pain outcome questionnaires are probably invalid for this population, and few questionnaires have been designed specifically for this complaint. The purpose of this study was to evaluate 3 questionnaires (Swiss Spinal Stenosis Score (SSS), Oxford Claudication Score (OCS) and Oswestry Disability Index (ODI)) and a Shuttle Walking Test (SWT). The Shuttle Walking Test, developed originally in respiratory medicine, shows promise as both a clinical measure and outcome measure for patients with neurogenic claudication. In an internal study, we have found that none of our patients selected for surgery can manage more than 200 metres. A fit adult can usually manage about 600 metres on this test. Study Design: Shuttle Walking Test (SWT), Swiss Spinal Stenosis Score (SSS), Oxford Claudication Score (OCS) and Oswestry Disability Index (ODI) were administered to patients with lumbar spinal stenosis (LSS) and neurogenic claudication. Objective: To determine reliability of SWT, SSS (Q1–12), OCS and ODI in LSS assessment. Methods: Thirty two clinic patients with LSS were assessed twice with one week between assessments to determine reliability. Retrospective data from 17 patients assessed before and 18 months after surgery for LSS were used to investigate use of reliability in a clinical setting. Results: Test-retest reliability was 0.92 for SWT, 0.92 for SSS, 0.83 for OCS and 0.89 for ODI (Intraclass correlation coefficient). Mean scores (percent) were SSS 51, OCS 45 and ODI 40. For 95% certainty of change between assessments for a single patient, SSS would need to change by 15, OCS by 20 and ODI by 16. Mean SWT was 150m, with change of 76m required for 95% confidence. Cronbach’s alpha was 0.91 for SSS, 0.90 for OCS and 0.89 for ODI. Change in ODI correlated most strongly with patient satisfaction after surgery (_=0.80, p< 0.001). Conclusions: Fluctuations in patient’s symptoms result in wide individual confidence intervals. Performance of SSS, OCS and ODI questionnaires are broadly similar. The condition specific SSS is most precise but not much better than the non-specific ODI. SWT gives a snapshot of physical function which is acceptable for group analysis. Use of SWT for individual assessment after surgery is feasible but multiple testing would improve sensitivity for change

Surgical decompression is the recommended treatment for patients with moderate to severe degenerative lumbar spinal stenosis (DLSS). Although complication risk has been shown to be higher with concomitant fusion, the success rate is not necessarily superior. This study analyzed the success rates of 58 DLSS patients treated with decompressive surgery. Twenty patients received concomitant instrumented fusion. Outcomes were measured with the Swiss Spinal Stenosis Questionnaire (SSSQ) completed pre-operatively and at least 12 months post-operatively (range 12 to 54 months). Overall, 63.8% of the patients had significant clinical improvement in Symptom Severity, 55.2% had significant clinical improvement in Physical Function, and 58.6% of the patients were at least somewhat satisfied; 43.1% (25/58) of the patients met all three criteria and were considered to be clinically successful. There were no statistically significant differences between the clinical success rates of the non-fusion and fusion groups, but the change in mean change of the Symptom Severity score for the fusion group was significantly greater than that of the non-fusion group. Also, patients with more severe pre-operative symptoms and more physical function restrictions had better success results than those patients with more mild symptoms and less restrictive physical function. The results of this study demonstrate that decompressive surgery with concomitant fusion does not impose a greater risk than decompressive surgery alone and the clinical results of the added fusion are somewhat superior to decompressive surgery alone

Aims. The aims of this study were first, to determine if adding fusion to a decompression of the lumbar spine for spinal stenosis decreases the rate of radiological restenosis and/or proximal adjacent level stenosis two years after surgery, and second, to evaluate the change in vertebral slip two years after surgery with and without fusion. Methods. The Swedish Spinal Stenosis Study (SSSS) was conducted between 2006 and 2012 at five public and two private hospitals. Six centres participated in this two-year MRI follow-up. We randomized 222 patients with central lumbar spinal stenosis at one or two adjacent levels into two groups, decompression alone and decompression with fusion. The presence or absence of a preoperative spondylolisthesis was noted. A new stenosis on two-year MRI was used as the primary outcome, defined as a dural sac cross-sectional area ≤ 75 mm. 2. at the operated level (restenosis) and/or at the level above (proximal adjacent level stenosis). Results. A total of 211 patients underwent surgery at a mean age of 66 years (69% female): 103 were treated by decompression with fusion and 108 by decompression alone. A two-year MRI was available for 176 (90%) of the eligible patients. A new stenosis at the operated and/or adjacent level occurred more frequently after decompression and fusion than after decompression alone (47% vs 29%; p = 0.020). The difference remained in the subgroup with a preoperative spondylolisthesis, (48% vs 24%; p = 0.020), but did not reach significance for those without (45% vs 35%; p = 0.488). Proximal adjacent level stenosis was more common after fusion than after decompression alone (44% vs 17%; p < 0.001). Restenosis at the operated level was less frequent after fusion than decompression alone (4% vs 14%; p = 0.036). Vertebral slip increased by 1.1 mm after decompression alone, regardless of whether a preoperative spondylolisthesis was present or not. Conclusion. Adding fusion to a decompression increased the rate of new stenosis on two-year MRI, even when a spondylolisthesis was present preoperatively. This supports decompression alone as the preferred method of surgery for spinal stenosis, whether or not a degenerative spondylolisthesis is present preoperatively. Cite this article: Bone Joint J 2022;104-B(12):1343–1351

Aims. We compared decompression alone to decompression with fusion surgery for lumbar spinal stenosis, with or without degenerative spondylolisthesis (DS). The aim was to evaluate if five-year outcomes differed between the groups. The two-year results from the same trial revealed no differences. Methods. The Swedish Spinal Stenosis Study was a multicentre randomized controlled trial with recruitment from September 2006 to February 2012. A total of 247 patients with one- or two-level central lumbar spinal stenosis, stratified by the presence of DS, were randomized to decompression alone or decompression with fusion. The five-year Oswestry Disability Index (ODI) was the primary outcome. Secondary outcomes were the EuroQol five-dimension questionnaire (EQ-5D), visual analogue scales for back and leg pain, and patient-reported satisfaction, decreased pain, and increased walking distance. The reoperation rate was recorded. Results. Five-year follow-up was completed by 213 (95%) of the eligible patients (mean age 67 years; 155 female (67%)). After five years, ODI was similar irrespective of treatment, with a mean of 25 (SD 18) for decompression alone and 28 (SD 22) for decompression with fusion (p = 0.226). Mean EQ-5D was higher for decompression alone than for fusion (0.69 (SD 0.28) vs 0.59 (SD 0.34); p = 0.027). In the no-DS subset, fewer patients reported decreased leg pain after fusion (58%) than with decompression alone (80%) (relative risk (RR) 0.71 (95% confidence interval (CI) 0.53 to 0.97). The frequency of subsequent spinal surgery was 24% for decompression with fusion and 22% for decompression alone (RR 1.1 (95% CI 0.69 to 1.8)). Conclusion. Adding fusion to decompression in spinal stenosis surgery, with or without spondylolisthesis, does not improve the five-year ODI, which is consistent with our two-year report. Three secondary outcomes that did not differ at two years favoured decompression alone at five years. Our results support decompression alone as the preferred method for operating on spinal stenosis. Cite this article: Bone Joint J 2024;106-B(7):705–712

Endoscopic spine surgery is a promising and minimally invasive technique for the treatment of disc herniation and spinal stenosis. However, the literature on the outcome of interlaminar endoscopic decompression (IED) versus conventional microsurgical technique (CMT) in patients with lumbar spinal stenosis is scarce. We analyzed 88 patients (IED: 36/88, 40.9%; CMT: 52/88, 59.1%) presenting with lumbar central spinal stenosis between 2018–2020. Surgery-related (operation time, complications, time to hospital release (THR), ASA score, C-reactive protein (CRP), white blood cell count (WBC), side (unilateral/bilateral), patient-reported (ODI, NRS (leg-, back pain), eQ5D, COMI), and radiological (preoperative dural sack cross-sectional area (DSCA), Shizas score (SC), left (LRH) and right (RRH) lateral recess heights, left (LFA) and right (RFA) facet angle) parameters were extracted.

Complication (most often re-stenosis due to hematoma and/or residual sensorimotor deficits) rates were higher in the endoscopic (38.9%) than microsurgical (13.5%) treatment group (p<0.01). Age, THR, SC, CRP, and DSCA revealed significant correlations with 3 weeks and 1 year postoperatively evaluated ODI, COMI, eQ5D, NRS leg, or NRS back values in our cohort. We did not observe significant differences in the endoscopic versus microsurgical group for the patient-reported outcomes.

Age, THR, SC, CRP, and DSCA revealed significant correlations with patient-centered outcomes and should be considered in future studies. Endoscopic treatment of lumbar spinal stenosis was similarly successful as the conventional microsurgical approach, although it was associated with higher complication rates in our single-center study experience. This was probably because of the surgeons' lack of experience with this method and the resulting different learning curve compared with the conventional technique.

With the increase in the elderly population, there is a dramatic increase in the number of spinal fusions. Spinal fusion is usually performed in cases of primary instability. However it is also performed to prevent iatrogenic instability created during surgical treatment of spinal stenosis in most cases. In literature, up to 75% of adjacent segment disease (ASD) can be seen according to the follow-up time.¹ Although ASD manifests itself with pathologies such as instability, foraminal stenosis, disc herniation or central stenosis.^1,2 There are several reports in the literature regarding lumbar percutaneous transforaminal endoscopic interventions for lumbar foraminal stenosis or disc herniations. However, to the best our knowledge, there is no report about the treatment of central stenosis in ASD. In this study, we aimed to investigate the short-term results of unilateral biportal endoscopic decompressive laminotomy (UBEDL) technique in ASD cases with symptomatic central or lateral recess stenosis.

The number of patients participating in the prospective study was 8. The mean follow-up was 6.9 (ranged 6 to 11) months. The mean age of the patients was 68 (5m, 3F). The development of ASD time after fusion was 30.6 months(ranged 19 to 42). Mean fused segments were 3 (ranged 2 to 8). Preoperative instability was present in 2 of the patients which was proven by dynamic lumbar x-rays. Preoperative mean VAS-back score was 7.8, VAS Leg score was 5.6. The preoperative mean JOA (Japanese Orthopaedic Association) score was 11.25. At 6th month follow-up, the mean VAS back score of the patients was 1, and the VAS leg score was 0.5. This improvement was statistically significant (p = 0.11 and 0.016, respectively). The mean JOA score at the 6th month was 22.6 and it was also statistically significant comparing preoperative JOA score(p = 0.011). The preoperative mean dural sac area measured in MR was 0.50 cm2, and it was measured as 2.1 cm² at po 6 months.(p = 0.012). There was no progress in any patient's instability during follow-up.

In orthopedic surgery, when implant related problems develop in any region of body (pseudoarthrosis, infection, adjacent fracture, etc.), it is generally treated by using more implants in its final operation. This approach is also widely used in spinal surgery.³ However, it carries more risk in terms of devoloping ASD, infection or another complications. In the literature, endoscopic procedures have almost always been used in the treatment of ventral pathologies which constitute only 10%. In ASD, disease devolops as characterized by wide facet joint arthrosis and hypertrophied ligamentum flavum in the cranial segment and it is mostly presented both lateral recess and santal stenosis symptoms (39%). In this study, we found that UBEDL provides successful results in the treatment of patients without no more muscle and ligament damage in ASD cases with spinal stenosis. One of the most important advantages of UBE is its ability to access both ventral and dorsal pathologies by minimally invasive endoscopic aproach. I think endoscopic decompression also plays an important role in the absence of additional instability at postoperatively in patients. UBE which has already been described in the literature given successful results in most of the spinal degenerative diseases besides it can also be used in the treatment of ASD. Studies with longer follow-up and higher patient numbers will provide more accurate results.

Abstract

Retrospective analysis of radiology reports of conventional MRI in 100 patients with definite spinal stenosis to determine the incidence of reported “foraminal stenosis”.

Prospective study of MRI including T2 coronal and T2 STIR coronal sequences in 57 patients with suspected stenosis. Three surgeons and one radiologist independently compared the diagnoses on conventional and coronal scans.

Patients with suspected spinal stenosis undergoing MRI.

Incidence of “foraminal stenosis” on radiologists' reports.

Diagnoses obtained by different scanning methods.

Retrospective analysis: “foraminal stenosis” called by radiologists in 46% using conventional axial and sagittal sequences.

Prospective study - 57 patients: conventional sequences diagnosed lateral recess stenosis well but also suggested foraminal stenosis in 33%. However, coronal sequences clearly showed no foraminal nerve compression.

In degenerative spondylolisthesis conventional scans suggested foraminal stenosis in 8 of 11 cases. Coronals showed no foraminal stenosis.

Excellent correlation was found in normal spines and in disc herniation. In far lateral disc herniation and isthmic spondylolisthesis, true foraminal stenosis was confirmed by conventional and coronal imaging.

Additional coronal MRI sequences prove that foraminal stenosis is over-diagnosed and is rare in spinal stenosis, but true foraminal nerve compression occurs in isthmic spondylolisthesis and far lateral disc herniation.

Aim: Spinal stenosis is a known entity in achondroplasia and a need for screening for the symptomatic children was identified in a tertiary limb reconstruction service. The aim of this study was to evaluate whether clinical and radiological imaging would identify the at risk group.

Materials and methods: 205 achondroplastic children were treated at our service in the last 20 years. A prospective clinical screening programme for spinal stenosis which also included the MRI imaging of entire spine was however introduced only in 1996. 26 patients were available for this study. Case notes were reviewed for clinical symptoms and neurological signs. MR images were assessed for stenosis especially at Cervico medullary junction and lumbar level. Canal diameters were measured at all spinal levels from CMJ to lumbo-sacral junction. Neurosurgical interventions were recorded. An attempt was made to identify high risk factors that required surgical intervention.

Results: Delayed milestones were observed in 7 patients. Positive history of back pain or radicular pain was obtained in 10 whereas 10 patients had symptoms of neurogenic claudication. Brisk reflexes and clonus were consistent findings. Severe foramen magnum narrowing was observed in 23 patients and 13 showed ‘kinking’ or ‘pinching’, suggesting severe compression. Of the 17 patients seen by neurosurgeons 6 required single or multiple surgical decompressions. Ventriculo-peritoneal shunt was inserted in 4. 5 children required CMJ decompression and one required lumbar canal decompression. There was a 7 mm difference in AP diameter measured on MRI at CMJ between the two non operated and operated groups. Female patients with delayed milestones and CMJ narrowing to less than 25 mm were identified as high risk.

Conclusion: The cause of increased morbidity and mortality in young achondroplasts is attributable to severe CM compression. Sudden death can occur by acute or gradual progressive encroachment of respiratory centre at medulla oblongata. We were able to identify symptomatic patients early before developing myelomalacia and cord changes by screening all symptomatic children with achondroplasia. We propose that female gender, especially with delayed milestones as another high risk factor. We stress upon the importance of developing a nationalised selective screening programme with guidelines in specialist orthopaedic and joint multi-disciplinary Skeletal Dysplasia clinics.

Objective: To assess the safety and outcome of laminectomy in patients with spinal stenosis operated at the age of 65 years or older. The relation between the duration of the symptoms and results was investigated.

Study Design: A retrospective chart analysis with up to 10 years follow-up.

Setting: The Spinal Care Unit, Meir Medical Center, Kfar Saba, Israel.

Material and Methods: The medical records of all patients who had laminectomy for spinal stenosis at the age of 65 or more in a 10 years period were reviewed. Assessment of pain, ability to perform the basic activities of daily living, transferring dressing and basing before and after the operation was done by a telephone interview. Patient’s self-estimation of the final result of the surgery was also recorded.

Results: Two hundred eight-three patients were eligible to participate in the study.

They were allocated into 3 groups according to the duration of symptoms before surgery. Group A with symptoms lasting up to 24 months, B with 25–48 months and C with symptoms lasting for more than 48 months. The average age at the time of the operation was 68.9, 72.6 and 71.3 years, respectively. Forty-eight patients died and 18 refused or were not able to participate in the study. The average time of follow-up was 43.3 months, 42.2 in group A, 47.4 in B and 42.8 in C.

No significant differences were noticed in the demographic, anesthetic and surgical parameters among the 3 groups.

There were no mortality cases in the immediate postoperative period. The overall complication rate was 43.5%, nearly identical in all 3 groups. Two patients had cerebrovascular accident and 5 had myocardial ischemia but no one turned into infarction. Mild complications included 11 urinary retention, 24 urinary tract infections and 11 patients with superficial wound infection. Twenty-two patients were re-operated along the follow-up period.

There was remarkable improvement in the perception of pain, walking distances and in the ability to perform basic activities of daily living in all 3 groups. Self-assessment of the final results disclosed 70% satisfied patients in group A, 67% in B and 67% in C.

Conclusion: Surgery for spinal stenosis in elderly patients is safe and often lead to significant relief of pain and improvement in the quality of life. Delaying surgery had no deleterious effect on the operative results.

Study Design

A prospective cohort study was carried out looking at the functional outcome and post-procedure translational segmental instability after multi-level lumbar decompression using a Hinge osteotomy technique.

We carried out a prospective study looking at the functional outcome and post-procedure segmental instability after lumbar decompression using a flip osteotomy technique that involved unilateral subperiosteal muscle dissection with hinging of the spinous processes thereby preserving the integrity of the posterior elements for unilateral or bilateral lumbar spine decompression.

Between February 2007 and February 2008, 51 patients (29 male and 22 female) diagnosed with degenerative and congenital lumbar stenosis with an average age of 60, underwent central and lateral canal decompression using the flip osteotomy technique. An average of two segments (range 1-3 segments) was decompressed. Patients with a history of previous spinal surgery, spinal fusion, existing degenerative spondylolisthesis or cauda equina syndrome were excluded.

All patients were followed up for a mean of 1.5 years. Five outcome measures were used – visual analogue scale for pain, Likert scale for functional status, symptom specific well-being score, general well-being score, number of days incapacitated in last 4 weeks. The outcomes measures were recorded pre-operatively, 6 weeks and one year post-operatively. Successful surgical outcome was defined as an improvement in at least four out of five outcome measures.

90% (46 patients) of patients had a successful surgical outcome. There was a statistically significant improvement in all outcome criteria (p<0.005) at the 6-week post-operative mark as compared to pre-operatively, with marginal improvement at one year post-surgery. There was no evidence of progressive lumbar segmental instability at one year post-operatively using our flip osteotomy technique

Decompression of the lumbar spine for lumbar stenosis using the flip osteotomy technique is a safe approach for one or multi-level stenosis with good outcomes and no evidence of significant iatrogenic segmental spinal instability.

We declare no conflict of interest and ethical approval was obtained

Introduction

Decompression is the gold standard surgical technique in patients with symptomatic spinal stenosis not responding to conservative management. We present an audit of outcomes in a population of patients undergoing this procedure over a four year period.

Symptomatic lumbar spinal stenosis is a common entity and increasing in prevalence. Limited evidence is available regarding patient reported outcomes comparing primary vs revision surgery for those undergoing lumbar decompression, with or without fusion. Evidence available suggest a lower rate of improvement in the revision group. The aim of this study was to assess patient reported outcomes in patients undergoing revision decompression, with or without fusion, when compared to primary surgery.

Patient data was collected from the Canadian Spine Outcomes Research Network (CSORN) database. Patients undergoing lumbar decompression without or without fusion were included. Patients under 18, undergoing discectomy, greater than two level decompressions, concomitant cervical or thoracic spine surgery were excluded. Demographic data, smoking status, narcotic use, number of comorbidities as well as individual comorbidities were included in our propensity scores. Patients undergoing primary vs revision decompression were matched in a four:one ratio according to their scores, whilst a separate matched cohort was created for those undergoing primary vs revision decompression and fusion. Continuous data was compared using a two-tailed t-test, whilst categorical variables were assessed using chi-square test.

A total of 555 patients were included, with 444 primary patients matched to 111 revision surgery patients, of which 373 (67%) did not have fusion. Patients undergoing primary decompression with fusion compared to revision patients were more likely to answer yes to “feel better after surgery” (87.8% vs 73.8%, p=0.023), “undergo surgery again” (90.1% vs 76.2%, P=0.021) and “improvement in mental health” (47.7% vs 28.6%, p=0.03) at six months. There was no difference in either of these outcomes at 12 or 24 months. There was no difference between the groups ODI, EQ-5D, SF 12 scores at any time point. Patients undergoing primary vs revision decompression alone showed no difference in PROMs at any time point.

In a matched cohort, there appears to be no difference in improvement in PROMS between patients undergoing primary vs revision decompression, with or without fusion, at two year follow-up. This would suggest similar outcomes can be obtained in revision cases.

Introduction

Limited physical activity (PA) is one indication for orthopaedic intervention and restoration of PA a treatment goal. However, the objective assessment of PA is not routinely performed and in particular the effect of spinal pathology on PA is hardly known. It is the purpose of this study using wearable accelerometers to measure if, by how much and in what manner spinal stenosis affects PA compared to age-matched healthy controls.

Hypothesis

Lumbar spinal stenosis (LSS) is diagnosed by a history of claudication, clinical investigation, cross-sectional area (CSA) of the dural sac on MRI or CT, and walking distance on the treadmill test. As radiological findings do not always correlate with clinical symptoms, additional diagnostic signs are needed. In patients without LSS, we observe the sedimentation of lumbar nerve roots to the dorsal part of the dural sac on supine MRI scans. In patients with LSS, this sedimentation is rarely seen. We named this phenomenon ‘sedimentation sign’ and defined the absence of sedimenting nerve roots as positive sedimentation sign for the diagnosis of LSS. We hypothesised that the new sedimentation sign discriminates between non-specific low back pain (LBP) and LSS.

Purpose of study: Self reported walking distance is a clinically relevant measure of function. Our aim was to report patient accuracy and understand factors that might influence perceived walking distance.

Method: A prospective cohort study. 103 patients were asked to perform one test of distance estimation and 2 tests of functional distance perception using pre-measured landmarks. Standard spine specific outcomes included the patient reported claudication distance, Oswestry disability index (ODI), Low Back Outcome Score (LBOS), visual analogue score (VAS) for leg and back, and Modified Zung Depression index (MZD).

Results: There are over-estimators and under-estimators. Overall the accuracy to within 10 yards was only 5% for distance estimation and 40% for the two tests of functional distance perception. Distance: Actual distance 121.4 yds; mean response 268yds (95% CI 192.8–344.15), Functional test 1 actual distance 32 yards; mean response 78.4 yds (95% CI 58.6–97.3), Functional test 2 actual distance 21.4yds; mean response 51.9yds (95% CI 38.3–65.5). Surprisingly patients over 60 years of age (n=43) are twice as accurate with each test performed compared to those under 60 (n=60) (average 70% overestimation compared to 140%; p=0.06). Patients in social class I (n=18) were more accurate than those in classes II–V (n= 85) (59% vs 131% p=0.13). There was a positive correlation between poor accuracy and increasing MZD (Pearson’s correlation coefficient 0.250; p=0.012). ODI, LBOS and other parameters measured showed no correlation.

Conclusions: Subjective distance perception and estimation is poor in this population. Patients over 60 and those with a professional background are more accurate.

Introduction: Operations inside the spinal canal are afflicted with a certain number of iatrogenic dural lesions. Incidence figures in the literature vary from 1 to 17% and are mainly based on retrospective studies. The Swedish Spine Register, SweSpine, provides a good possibility to study the incidence in a prospective patient material.

Patients and Methods: During 5 years more than 9 000 patients had surgical treatment for lumbar disc herniation or lumbar spinal stenosis and were registered according to the protocol of the Swedish Spine Register. One year follow-up data were present for 74 % of the patients. Pre- and postoperative data are entirely based on questionnaires answered by the patient whereas surgical data are completed by the surgeon. Complication and re-operation registration is included.

Mean patient age for LDH was 45 (12–88) years, for spinal stenosis 68 (27–93) years and 56% of the disc herniation patients and 43% of the spinal stenosis patients were males. Most common level for LDH operation was L5/S1 followed by L4/L5 and for spinal stenosis L4/L5 followed by L3/L4.

The one-year result was studied.

Results: The incidence of dural lesion in lumbar disc herniation surgery was 2.7% and in spinal stenosis decompression 7.3%. The risk for dural lesion was more than doubled in patients with previous surgery which, thus, was a significant but also the only risk factor. At one year after surgery the result was similar for patients with and without dural lesion when VAS pain, ODI, SF-36 and patient graded global assessment were studied. Correlation between previous surgery and inferior outcome was seen but was not affected by the dural lesion as such. Three and 5% respectively in the groups were subjected to repeat surgery before discharge from the hospital.

The lost-to follow-up group (26%) had similar pre-operative demographics and the same incidence of dural lesion as those followed-up.

Conclusion: In a large prospectively studied material, the incidence of dural lesion in lumbar disc herniation surgery was 2.7% and in decompressive spinal stenosis surgery 7.3%. Previous surgery was a significant risk factor for dural lesion. The dural lesion as such did not negatively influence the one-year outcome.

Purpose: Self reported walking distance is a clinically relevant measure of function, our aim was to report patient accuracy and understand factors that might influence perceived walking distance.

Method: A prospective cohort study. 103 patients were asked to perform one test of distance estimation and 2 tests of functional distance perception using pre-measured landmarks. Standard spine specific outcomes included the patient reported claudication distance, Oswestry disability index (ODI), Low Back Outcome Score (LBOS), visual analogue score (VAS) for leg and back, and other measures.

Results: There are over-estimators and under-estimators. Overall the accuracy to within 10 yards was only 5% for distance estimation and 40% for the two tests of functional distance perception. Distance: Actual distance 121.4 yds; mean response 268yds (95% CI 192.8–344.15), Functional test 1 actual distance 32 yards; mean response 78.4 yds (95% CI 58.6–97.3) Functional test 2 actual distance 21.4yds; mean response 51.9yds (95% CI 38.3–65.5). Surprisingly patients over 60 years of age (n=43) are twice as accurate with each test performed compared to those under 60 (n=60) (average 70% overestimation compared to 140%; p=0.06). Patients in social class I (n=18) were more accurate than those in classes II–V (n= 85): There was a positive correlation between poor accuracy and increasing MZD (Pearson’s correlation coefficient 0.250; p=0.012). ODI, LBOS and other parameters measured showed no correlation.

Conclusions: Subjective distance perception and estimation is poor in this population. Patients over 60 and those with a professional background are more accurate.

Ethics approval: not required

Interest Statement: none

Since neurological claudication is a major symptom in lumbar spinal stenosis (LSS), walking distance is commonly used as a measure of the severity and surgical outcome in LSS. The aim of this study was to compare self-reported and treadmill-measured walking distances in a trial, in which 94 patients with moderate LSS had been randomized into conservative and surgical treatment. Among the 44 patients in conservative treatment, the treadmill-measured walking distance was more reproducible after 6 months than the self-reported distance; the intraclass correlation coefficients were 0.75 and 0.41, respectively. Among all the patients at baseline, the agreement between self-reported and measured walking distance was satisfactory (intraclass correlation 0.57), although male patients overwhelmed their performance by 200 meters. Such a shift was not found in women. For walking distance categorized as < 400, 400–1249 and ≥ 1250 meters, there was a fair agreement between self-report and treadmill (weighed kappa 0.42). However, when the analysis was restricted to those whose walking distance was restricted to < 1250 meters, the corresponding agreement was poor (intraclass correlation 0.26). The self-reported walking distance was closely correlated with Oswestry index at baseline (r = 0.26), and changes in these outcomes from randomization to the follow-up of 6 months showed a strong correlation with each other (r = 0.37). We conclude that walking distance is a fundamental element of disability in LSS. Self-reported walking distance seems to be an appropriate clinical tool, but its limited precision in relation to treadmill-measured distance must be considered, when walking ability is severely restricted.