Comparison of instrumented anterior interbody fusion with instrumented circumferential lumbar fusion.

Posterior lumbar interbody fusion (PLIF) restores disc height, the load bearing ability of anterior ligaments and muscles, root canal dimensions, and spinal balance. It immobilizes the painful degenerate spinal segment and decompresses the nerve roots. Anterior lumbar interbody fusion (ALIF) does the same, but could have complications of graft extrusion, compression and instability contributing to pseudarthrosis in the absence of instrumentation. The purpose of this study was to assess and compare the outcome of instrumented circumferential fusion through a posterior approach [PLIF and posterolateral fusion (PLF)] with instrumented ALIF using the Hartshill horseshoe cage, for comparable degrees of internal disc disruption and clinical disability. It was designed as a prospective study, comparing the outcome of two methods of instrumented interbody fusion for internal disc disruption. Between April 1994 and June 1998, the senior author (N.R.B.) performed 39 instrumented ALIF procedures and 35 instrumented circumferential fusion with PLIF procedures. The second author, an independent assessor (S.M.), performed the entire review. Preoperative radiographic assessment included plain radiographs, magnetic resonance imaging (MRI) and provocative discography in all the patients. The outcome in the two groups was compared in terms of radiological improvement and clinical improvement, measured on the basis of improvement of back pain and work capacity. Preoperatively, patients were asked to fill out a questionnaire giving their demographic details, maximum walking distance and current employment status in order to establish the comparability of the two groups. Patient assessment was with the Oswestry Disability Index, quality of life questionnaire (subjective), pain drawing, visual analogue scale, disability benefit, compensation status, and psychological profile. The results of the study showed a satisfactory outcome (score< or =30) on the subjective (quality of life questionnaire) score of 71.8% (28 patients) in the ALIF group and 74.3% (26 patients) in the PLIF group (P>0.05). On categorising Oswestry Index scores into "excellent", "better", "same", and "worse", we found no difference in outcome between the two groups: 79.5% (n=31) had satisfactory outcome with ALIF and 80% (n=28) had satisfactory outcome with PLIF. The rate of return to work was no different in the two groups. On radiological assessment, we found two nonunions in the circumferential fusion (PLIF) group (94.3% fusion rate) and indirect evidence of no nonunions in the ALIF group. There was no significant difference between the compensation rate and disability benefit rate between the two groups. There were three complications in ALIF group and four in the PLIF (circumferential) group. On the basis of these results, we conclude that it is possible to treat discogenic back pain by anterior interbody fusion with Hartshill horseshoe cage or with circumferential fusion using instrumented PLIF.

Anterior lumbar interbody fusion: does stable anterior fixation matter?

The purpose of this study was to compare the outcome of anterior lumbar interbody fusion without instrumentation (uninstrumented ALIF) against that with stable anterior cage fixation using Hartshill horseshoe instrumentation (ALIF-HH) for similar severity of disc disease. Between April 1994 and June 1998 the senior author N.R.B. performed 29 instrumented ALIF procedures with a Hartshill horseshoe cage (ALIF-HH). Between 1990 and 1998, the other senior author (J.M.H.), together with another senior consultant orthopaedic surgeon, performed 27 noninstrumented ALIF procedures using corticocancellous iliac crest autograft. All the patients in both groups had single-level fusion. An independent assessor (S.M.) performed the entire review. The mean follow-up was 4.7 years (2.3-7.9 years) in the uninstrumented ALIF group and 3.0 years (2.1-4.4 years) in the ALIF-HH group. There was subsidence of graft in four patients in the uninstrumented ALIF group. It is reasonable to assume that there was no pseudarthrosis in the ALIF-HH group. This difference was statistically significant (two-sided P-value =0.0425). On subjective score assessment, there was a satisfactory outcome (score0.05). On classification by the Oswestry Index into four categories, we found no difference in outcome between the two groups: 83.3% ( n=20) had a satisfactory outcome (defined as Excellent or Better) with ALIF and 77.8% ( n=21) had a satisfactory outcome with ALIF-HH using the Oswestry Disability Index for post-operative assessment ( P>0.05). The results of this study indicate that the Hartshill horseshoe cage does improve the fusion rate, but does not affect clinical outcome.

Circumferential and posterolateral fusion for lumbar disc disease.

Clinical outcome of low back fusion is unpredictable. There are various reports discussing the merits and clinical outcome of these two procedures. The patients were selected from a population of patients who had chronic low back pain unresponsive to conservative treatment. Thirty-six instrumented posterolateral fusions and 35 instrumented circumferential fusions with posterior lumbar interbody fusions were done simultaneously. Preoperative radiographic assessment included plain radiographs, magnetic resonance imaging scans, and provocative discography in all the patients. Posterolateral fusion or anterior lumbar interbody fusion was done for internal disc disruption. The Oswestry disability index, subjective scoring, and assessment of fusion were done at a minimum followup of 2 years. On subjective scoring assessment there was a satisfactory outcome of 63.9% (23 patients) in the posterolateral fusion group and 82.8% (29 patients) in the posterior lumbar interbody fusion group. On assessment by the Oswestry index no difference was found in outcome between the two groups. The posterolateral fusion group had a 63.9% satisfactory outcome and the posterior lumbar interbody fusion group had an 80% satisfactory outcome using the Oswestry disability index for postoperative assessment. There was 61.1% improvement in working ability in the posterolateral fusion group and 77.1% improvement in the posterior lumbar interbody fusion group which was not statistically significant. The authors consider instrumented circumferential fusion with posterior lumbar interbody fusion better than instrumented posterolateral fusion for managing chronic disabling low back pain.

Outcome of posterior lumbar interbody fusion versus posterolateral fusion for spondylolytic spondylolisthesis.

STUDY DESIGN: This retrospective study analyzed the outcome of 44 patients who had decompression, pedicle screw-rod fixation, and fusion for Grades 1 and 2 spondylolytic spondylolisthesis. OBJECTIVE: To evaluate the outcome of two methods for stabilization and fusion: posterolateral fusion and circumferential fusion involving posterior lumbar interbody fusion and posterolateral fusion for low grades of isthmic spondylolisthesis. SUMMARY OF BACKGROUND DATA: It has been suggested that stabilization with instrumented fusion is somewhat unpredictable due to lack of anterior support. Does circumferential fusion using posterior lumbar interbody fusion circumvent all the problems, and is it better than posterolateral fusion clinically? METHODS: A single surgeon treated 21 patients with instrumented posterolateral fusion and 23 patients with instrumented circumferential fusion, (i.e., posterior lumbar interbody fusion, and posterolateral fusion. These two groups were compared for clinical outcome, fusion rate, and correction of slippage. RESULTS: The minimum follow-up period for the patients was 2.1 years. The clinical satisfactory outcome on the Oswestry index was 81% for posterolateral fusion and 69% for posterior lumbar interbody fusion. The subjective outcome was 86% and 65%, respectively, for the two groups (P > 0.05). However, a consideration of subjective scores showed that three patients (14.3%) in posterolateral fusion group and eight patients (34.8%) in posterior lumbar interbody fusion group had an unsatisfactory outcome (P = 0.0135), which was very significant. There were two nonunions in the posterolateral fusion group and none in the posterior lumbar interbody fusion group (P > 0.05). The correction of slippage and the loss of correction at the last follow-up assessment was better in the posterior lumbar interbody fusion group, although this was not statistically significant (P > 0.05). Radicular symptoms and neurologic improvement were statistically similar between the two groups. CONCLUSIONS: Posterolateral fusion has a better clinical outcome in low grades of isthmic spondylolisthesis, although posterior lumbar interbody fusion is more predictable in maintaining correction and achieving union. Careful patient selection is needed for each operation, and adjacent level disc degeneration may influence the procedure offered to the patient.

Does provocative discography screening of discogenic back pain improve surgical outcome?

The value of preoperative provocative discography in the setting of discogenic low back pain was investigated by evaluating surgical outcomes. Seventy-three consecutive patients who underwent posterolateral interbody and posterior spinal arthrodesis for discogenic low back pain refractory to nonoperative management were reviewed. Chronologically, the first 41 patients (group A) were indicated without discography, whereas the remaining 32 (group B) had been indicated only if their pain had been reproduced during disc injection. The two groups were similar in demographic, psychometric, and radiologic parameters. Average follow-up time in group A was 2.8 years and in group B it was 2.4 years, both with a 2-year minimum. Using modified Oswestry scoring, group A and group B patients had satisfactory outcomes of 75.6% and 81.2%, respectively. This difference was neither statistically significant nor suggestive. In this study, provocative discography screening did not improve surgical outcomes after circumferential fusion for lumbar discogenic back pain.

Containment and stabilization of bone graft in anterior lumbar interbody fusion: the role of the Hartshill Horseshoe cage.

The Hartshill Horseshoe cage is a titanium implant that is inserted after removal of the disc in anterior lumbar interbody fusion. The authors use corticocancellous iliac crest graft, which is contained within the confines of the implant. The cage and the motion segment are stabilized by inserting screws into the adjacent vertebral bodies through holes in the implant. Between 1995 and 1997, 27 patients had this implant inserted. Minimum follow-up was 2.1 years (mean: 2.9 years). Patients were assessed using the Oswestry disability index, a core set of six questions, a pain drawing, and psychometrically using the Zung Depression Scale and the Modified Somatic Perception Questionnaire. The patients' subjective assessment was also obtained. Twenty-one patients (77.8%) improved significantly on the Oswestry disability index and 22 patients (81.5%) improved by subjective assessment using the "core set" of six questions. There was no evidence of pseudarthrosis, loosening, or osteolysis around the implant or the screws. The cage prevents graft extrusion, collapse, or sinkage through the endplates. The normal lumbar lordosis is restored and, by restoring normal intervertebral disc space height, the Horseshoe opens up the neural foraminae. This cage stabilizes the motion segments and secures the graft, preventing micromotion at the graft vertebral body interface and providing a conducive environment for fusion.

Ultrasound imaging and secondary screening for congenital dislocation of the hip.

We report the preliminary results of a continuing prospective evaluation of a screening programme for congenital dislocation of the hip (CDH) which uses ultrasound imaging to provide delayed selective screening to complement neonatal clinical screening. Of 26,952 births in the Southampton district, 1894 infants were referred for secondary screening because of a clinical abnormality or the presence of a predetermined risk category for CDH. Pavlik harness treatment was required for only 118 infants, giving a treatment rate of 4.4 per 1000 births. Of those referred with clinical instability, 35% did not require treatment. Dislocation or subluxation was detected in 17 of 643 infants referred only because they fell within one of three risk categories: breech presentation, foot deformity and family history. All 17 had normal clinical examinations and cases were discovered in each category. Six children presented with CDH after 12 weeks of age, giving a late presentation rate of 0.22 per 1000 births. All had normal clinical examinations within 24 hours of birth and none was in a risk category. Surgery has been required in ten children, giving a surgical treatment rate of 0.37 per 1000 births. We conclude that, in Southampton, delayed selective secondary screening with ultrasound is more effective than clinical screening alone. It targets treatment to those infants who need it, and reveals a number of dislocated and subluxed hips that would otherwise be missed.

Development of a degradable composite for orthopaedic use: mechanical evaluation of an hydroxyapatite-polyhydroxybutyrate composite material.

This study evaluates the mechanical properties of a composite material comprising polyhydroxybutyrate with hydroxyapatite added in proportions varying from 0 to 50%. Among the three methods of production, injection moulding was found to result in the most satisfactory mechanical properties. The tensile and compressive strength and the modulus of elasticity of composite produced in this way fell within the range for fresh human bone from different anatomical sites. With the additional advantages of biocompatibility, biodegradability and the potential for piezoelectric stimulation of new local bone formation, it was concluded that the injection-moulded composite material has considerable potential for use in orthopaedic surgery, both as a material to construct certain orthopaedic implants and as an alternative to corticocancellous bone graft.

The selection of wires for sublaminar fixation.

The authors report a comparative biomechanical study of the suitability of four types of stainless steel wire for sublaminar fixation. Tensile and fatigue tests were performed on wires in the configuration used at surgery. They conclude that annealed 18-gauge (1.2 mm) wire should be used at each end of a scoliosis fusion, at the upper end of a lumbar fusion, and throughout for thoracolumbar fractures. Cold-worked 20-gauge (0.87 mm) wire may be used in all other situations, but the use of annealed 20-gauge wire should be restricted to the cervical spine. The authors emphasize the importance of achieving the correct balance between wire stiffness and flexibility, of care in the handling of wires, and of proper technique in achieving secure fixation.

Cemented total hip arthroplasty in patients younger than 50 years of age. Ten- to 18-year results.

In ten- to 18-year clinical and roentgenographic results of 46 cemented total hip arthroplasties (THAs) in 34 patients younger than 50 years of age, surviving primary implants achieved a mean Harris hip score of 93 points. Survivorship analysis revealed failure rates of 2% at seven years, 10% at ten years, and 12.7% at 12 years. Roentgenographic analysis demonstrated either no signs of failure or benign mechanical failure modes in 73% of cases. No correlation was found between the Charnley category or the diagnosis and the clinical or the roentgenographic assessments. Cemented THA in the young would appear to provide durable restoration of hip function, with a revision rate similar to that reported in the elderly. For reliable early detection of progressive mechanical failure before loss of bone stock occurs, annual roentgenographic examinations are advisable.

Assessment of the menisci and cruciate ligaments: an audit of clinical practice.

The reliability of clinical assessment of the knee was evaluated in 203 patients using magnetic resonance imaging (MRI). Neither the mechanism of injury nor clinical symptoms were useful indicators of the type of pathology. Physical signs proved insufficiently sensitive in detecting abnormalities. Overall, the accuracy of clinical diagnosis was 80.8 per cent for the anterior cruciate ligament, 62.9 per cent for the medial meniscus and 74.9 per cent for the lateral meniscus. Accurate investigations allow arthroscopy to be targeted to those likely to obtain therapeutic benefit. Reliance upon clinical judgement alone would have resulted in an 89 per cent increase in arthroscopic procedures. Investigations such as MRI or arthrography are concluded to be cost-effective methods of avoiding unnecessary hospitalization, morbidity and waste of limited resources.

Magnetic resonance imaging of meniscal and cruciate injuries of the knee.

We investigated 133 knees with suspected meniscal or cruciate injuries by magnetic resonance imaging, and compared the findings with those at arthroscopy. MRI was found to be highly sensitive, specific and accurate in the evaluation of the menisci and the anterior cruciate ligament.