Purpose: Claudication is a common complaint of elderly patients. Lumbar spinal stenosis (LSS) and peripheral arterial disease (PAD) are the two main etiologies, producing neurogenic and vascular claudication respectively. Physicians initially diagnose claudication based on a “typical” symptom profile. The reliability of this symptom profile to accurately diagnose LSS or PAD as a cause of claudication is unknown, leading to the potentially unnecessary utilization of expensive and overly sensitive imaging modalities. Furthermore, clinicians rely on this symptom profile when directing treatment for patients with concurrent imaging positive for LSS and PAD. This study evaluates the reliability of various symptom attributes, which classically have characterized and differentiated the two.

Method: Patients presenting at a tertiary care center’s vascular or spine clinics with a primary complaint of claudication were enrolled in the study. Diagnosis of either LSS or PAD was confirmed with imaging for each patient. They answered 14 questions characterizing their symptoms. Sensitivity, specificity, positive and negative likelihood ratio (PLR and NLR) was determined for each symptom attribute.

Results: The most sensitive symptom attribute to rule out LSS is “triggering of pain with standing alone” (0.96). Four symptom attributes demonstrated a high PLR and three had low NLR for diagnosing neurogenic claudication (PLR= 3.08, 2.51, 2.14, 2.9; NLR=0.06, 0.29, 0.15). In vascular patients, calf symptoms and alleviation of pain with simply standing had a high PLR and NLR (PLR= 3.08 and 4.85; NLR= 0.31 and 0.36).

Conclusion: Only four of 14 “classic” symptom attributes are highly sensitive for ruling out LSS, and should be considered by primary care physicians before pursing expensive diagnostic imaging. Six symptom attributes should be relied upon to differentiate LSS and NLR. Numbness, pain triggered with standing alone, located in the buttock and thigh, and relieved following sitting, are symptom attributes which reliably characterize neurogenic claudication.

Introduction: Hypothesis:- Posterior lumbar interbody fusion (PLIF) produces improvement in the MOS Short Form 36 (SF36) scores comparable to that seen in total hip replacement.

Current consensus holds the surgical treatment of lower back pain as less effective or predictable than interventions performed in most other orthopaedic subspecialties. Detailed clinical and economic outcome studies are vital to justify its use in routine practice. This prospective study presents medium to long-term clinical outcome scores for PLIF which are compared with those of an operation that might be considered a modern orthopaedic gold-standard: total hip arthroplasty.

Methods: The authors present 100 consecutive PLIF operations performed by the senior author between 1997 and 2004. SF36, Oswestry Disability Index (ODI), Visual Analogue Scores (VAS) and walking distances were prospectively collected and analysed in the post-operative period. Results were compared to the SF36 healthy population norms and with the outcome scores of standard total hip replacement available in the literature.

Results: The mean pre-operative ODI was 49. 12 months following surgery this improved to 22. All outcomes as measured by SF36 improved following surgery. The VAS for back pain improved from 8.5 pre-operatively to 3.21 post-operatively. Leg pain improved from 6.98 to 2.85. Improvements in the SF36 scores were similar to those seen in hip arthroplasty.

Discussion: The hypothesis has been proven. The gains in function following spinal fusion are comparable with those seen in hip arthroplasty. In the authors’ opinion PLIF is an effective procedure in an appropriately selected patient population.

Objective: Axially loaded MRI simulates imaging of the lumbar spine in the standing position and is useful in the assessment of spinal stenosis[1]. This study determines the ability of axially loaded spinal MRI to assess Cobb angle in patients with idiopathic scoliosis.

Design: Prospective study. Newly diagnosed patients with idiopathic scoliosis were referred for MRI of the whole spine. Cobb angle measurements were made from erect AP spinal radiographs prior to MRI. Coronal MR images of the thoracic and/or lumbar spine were obtained prior to and following loading of the spine in an MR compatible compression device (Dynawell). Cobb angle measurements were made on unloaded and loaded MRI studies using the same reference points as on radiographs. Radiographic and MRI Cobb angle measurements were compared. Informed consent was obtained from all patients and the study was approved by the local Ethics Committee.

Subjects: Five patients, all females with mean age 14 years (range 12–16 years) were included in the study. Outcome Measures: Six curves were compared on pre-referral erect radiographs, unloaded and loaded MRI studies, 2 in the thoracic region and 4 in the thoracolumbar region.

Results: Curve characteristics and Cobb angle measurement on radiographs vs. axial unloaded and loaded MRI were as follows: Curve 1; T4-T12, 45°, 36° and 41°. Curve 2; T10-L4, 52°, 22° and 30°. Curve 3; T10-L4, 45°, 36° and 38°. Curve 4; T6-T10, 42°, 22° and 22°. Curve 5; T11-L3, 43°, 32° and 43°. Curve 6; T11-L3, 34°, 11° and 31°

Conclusions: Axial loading increases MRI Cobb angle measurements compared to unloaded studies. Initial results suggest that axial loaded MRI using the Dynawell Compression device may allow comparative measurement of Cobb angle to erect radiographs in the thoracolumbar region, but not in the thoracic region. This is likely related to the loading characteristics of the compression device, which is designed to concentrate loading in the lumbar region. Modification to include loading of the thoracic spine may improve results. The technique has the potential to replace radiography and thus reduce radiation burden to young adolescents with some types of idiopathic scoliosis.

Aim: To test the null hypothesis that interbody cage fusion does not improve clinical outcome.

Methods and materials: This is a prospective study of 87 patients. Seventy-one of the 87 patients followed to the conclusion of the study at two years. Inclusion criteria: Patients undergoing interbody cage fusion with the Ray threaded cage, made of Titanium, and posterior stabilisation with Diapason pedicle screw instrumentation, all operated by the same surgeon. Exclusions: Surgery for infection, or tumour. Tools used for assessment: Oswestry low back pain questionnaire; Visual analogue pain score (VAS); SF36 general health questionnaire. Assessment time points were 1) Pre-op, and post-operatively at 2) 3 months, 3) 6 months, 4) 1 year and 5) 2 years. SF 36 was introduced later recruiting 71 of the 87 patients.

Results: There were 31 males and 56 females. Average age was 46 years (range 14–76) Fifty-one of the patients had no previous surgery, while 36 had previous surgery.

There was a significant, gradual improvement in symptoms of an average of 20 points (p< .001) over the first year on the Oswestry score. However, this plateaued between the first and second years. Over two years there was a greater than 20 point increase in all but three concepts of SF36, general health, reported health and mental health improving around 15 points (p< .001). Sixty-five per cent of the patients reported an overall improvement and 12% were worse, with most changes occurring in the first year.

In assessing the symptoms with Oswestry questionnaire there was a significant difference between first time and revision surgical groups. The revision group showed an improvement of 11 points (p< .001) at two years, most occurring in the latter part of the first year followed by some deterioration between the first and second years. In the primary surgery group there is a 28 point (p< .0001) improvement by two years. Most of the improvement in the primary group is achieved by the first six months.

Conclusions: Interbody fusion can significantly improve health and function assessed by Oswestry and SF36 outcome tools. Additional observations – unsatisfactory outcome in 12% of patients; expected progress at fixed times after surgery can assist planned rehabilitation. This paper introduces the concept of time staged assessment of symptoms in spinal fusion.

Introduction: There have been reports of anterior fusion surgery advocating the routine use of interbody spacers in the lumbar and low thoracic spine. In contrast to these, many surgeons feel that the routine use of inter-body spacers is not warranted, provided appropriate surgical technique is used for discectomy, screw placement, and solid rod contouring. Rather, the insertion of spacers may, in fact, hinder correction of the overall deformity. Our hypothesis was that it is possible to create a satisfactory sagittal profile without the use of interbody spacers.

Methods and results: Study design: Retrospective examination of X-rays and appropriate notes. Patients of the senior author who had undergone an instrumented anterior fusion for scoliosis were reviewed. Some of these patients underwent a second stage posterior fusion to the same level distally. Analysis of the X-rays and notes was performed on a group of 27 patients who had undergone their surgery from July 1996 to December 2000. Follow-up varied from six months to three years.

Inclusion criteria: Diagnosis was adolescent idiopathic scoliosis. All surgery carried out by the one surgeon (BT). Anterior fusion, with a solid rod, extending into the lumbar spine. There were 15 who had anterior fusion only, and 12 who also underwent posterior fusion. The difference between the groups was that of the nature of the curves. One of the patients had the posterior fusion on a second admission for thoracic curve progression after anterior lumbar fusion. Lowest instrumented levels were 6 to L2, 15 to L3, and 6 to L4.

Variables measured: Assessment of AP and sagittal alignment was made, as was fusion across the levels. Methods and problems encountered with data collection will be discussed. Variables were AP Cobb; Sagittal angle variables were 1) L1-S1 2) TIV-LIV 3) LIV-S1 4) L4 5) S1. These were compared with previously published data; difficulties in comparison to ‘Normal’ will be discussed.

Results: There was no incidence of metalware failure, and no bone/screw interface problems. There was no loss of correction in those cases where follow-up was possible. Union was slow compared to some previously published series. Despite a tendency for a relative loss of lordosis across the fusion, overall lumbar lordosis was maintained within accepted values, and the fusion construct angle was within accepted limits. There was minimal change in Cobb angle of the fusion construct with time.

There have been four cases of < 25% retro-listhesis at the upper end of the constructs. These have not produced neurological symptoms, but as yet the significance clinically is unknown.

Conclusion: At this stage the authors feel that routine use of interbody spacers is not justified, as complications without their use have not been forthcoming.

Aim: To test the null hypothesis that plain X-rays can provide the same assessment of sacral screw placement as CT.

Introduction: Engaging the anterior cortex of the sacrum provides additional strength to fixation and is a goal of surgery. The sacrum with its unique anatomy makes it a difficult bone to assess screw placement radiologically. This study examines the positioning of sacral screws as seen on X-rays and compares the result with spiral CT “gold standard”.

Materials and methods: Inclusion criteria: Sacral fixation using Diapason (Stryker) Titanium pedicle screws by one surgeon. Spiral CT, plain AP and lateral X-rays of the sacrum. Exclusion criteria: X-rays with more than three level fixation.

There were 66 patients (132 S1 screws). Surgical technique engaged the anterior cortex to enhance fixation. Two independent observers (a musculoskeletal radiologist and spinal fellow) who were blinded to outcome, reported findings in forms with constrained fields. Assessment of plain X-ray and CT was at separate times not less than three weeks apart. Variables noted: Screw position in pedicle, screw tip position, and angle of screw (sagittal on axial CT scans).

AP X-ray was divided, for each screw, into nine zones based on the first sacral foramina. The position of the screw tip in the zones was noted. The lateral X-ray was divided into three zones to note the tip of the screw in relation to the cortex. The extent of screw protrusion was measured. X-ray technique: Supine AP centred on fusion and lateral X-ray standing, X-ray source 200 cm from the film. CT: Images acquired on Picker PQ 6000 spiral CT with collimated thickness of 3 mm, pitch 1.25 and reconstructive index of 1.Para-sagittal and coronal reconstructions. Spiral CT was used to note the position of the screw within the pedicle and the relation of the screw tip to the anterior cortex. For screws within the pelvis any structure in close proximity was noted.

Results: On CT 10% of the screws had breached the pedicle compared with 2% on the plain X-rays. Anterior cortical perforation had been achieved in 48 out of 132 screws on CT. The sensitivity of the plain X-rays to perforation was 40% with a specificity of 92%. There was an average under estimation of the extent of screw perforation by 4.4 mm (95% confidence ±1 mm). There was a correlation between the position of the screw tip on the AP X-ray and the sensitivity of the lateral X-ray to detect a perforation. The sensitivity ranged from 52% for zone 1 to 15% in zone 8. 15/31 perforations were missed in zone 1, compared with 11/13 in zone 8. For screws penetrating 5 mm or more, in zone 8, 9 out of 10 were missed on lateral X-rays.

Eighty-five screws were placed at an angle of less than or equal to 25° to the sagittal; this included 28 out of 34 screws placed in zone 8. The inter-observer variance of screw angle measurement was 1.1° and intra-observer difference 1.7°. Overall 95% confidence of a single measurement was ±3.3°.

Conclusion: Plain X-rays and CT do not provide the same assessment of sacral screw placement. This is particularly true for sagitally placed screws with screw tips in zones 7–8.