Introduction We report the two-year clinical outcome of a prospective randomised trial comparing Femoral Ring Allograft (FRA) to a Titanium Cage (TC) in circumferential lumbar spinal fusion.

Methods 83 patients recruited to the study fulfilled strict entry requirements (> 6 months chronic discogenic low back pain, failure of conservative treatment, one or two-level discographically proven discogenic pain source). 38 patients were randomised to receive FRA, 45 patients were randomised to receive TC. Posterior stabilisation was achieved with translaminar or pedicle screws. Patients completed questionnaires including Oswestry Disability Index (ODI), Visual Analogue Scale (VAS) and the Short-Form 36 (SF-36) pre-operatively and 6, 12 and 24 months post-operatively.

Results Results were available for all 83 patients with a mean follow-up of 26.5 months (range 24–75 months). Baseline demographic data (age, sex, smoking history, number of operated levels, pre-operative outcome measures) showed no statistical difference between groups (p< 0.05). For patients receiving the FRA, mean VAS (back pain) improved 2.0 points (p=0.01), mean ODI improved 14 points (p=< 0.01), and mean SF-36 scores improved by > 11 points in all domains (p< 0.03) except general health and emotional role. For patients receiving the TC, mean VAS improved 1.2 points (p=0.002), mean ODI improved 5 points (p=0.02); SF-36 improved significantly in only one of eight domains (bodily pain).

Discussion Clinical outcome following circumferential lumbar fusion with FRA readily achieves the accepted mean clinically important differences (MCID). Fusion with TC does not achieve the MCID. The use of TC for circumferential lumbar fusion appears not to be justified.

We analysed the functional outcome (Oswestry Disability Index) after technically and radiologically successful lumbar fusion in 39 non-compensation seeking patients with chronic low back pain, who had a High Intensity Zone (HIZ) – positive MRI and subsequently underwent discography. The average follow-up was 33 months. The HIZ-positive, discogrampositive group was the only one with statistically significant improvement. The HIZ-positive, discogram-negative group had the worst outcome. Relying only on the HIZ fails to identify the group of patients who would have had negative discography at the same levels. Therefore the presence of HIZ alone should not dictate treatment plan without discography confirmation.

In a prospective non-randomised study, 28 patients underwent laparoscopic assisted transperitoneal anterior interbody fusion at the lumbosacral junction with the BAK cage over a 3-year period. In laparoscopic group, there were significantly lower blood losses (P< 0. 005), operating times [P< 0. 05], analgesic requirements [P< 0. 05] and postoperative rehabilitation [P< 0. 05). 8 patients developed post-operative nerve root pain, 5 of which settled with nerve root blocks, and there was 1 case of donor site infection. Intraoperative complications included 1 CIA tear, 2 CIV tears and 3 open conversions [11%]. 6 cases [24%] required further surgery at a mean of 14 months [range 4–29 months]. 20 laparoscopic cases completed a subjective self-assessment score with 4 [20%] excellent results, 5 [25%] good, 2 [10%] fair, 8 [40%] same and 1 [5%] worse.

The preoperative Visual Analogue Pain Score [VAPS] and Oswestry Disability Index [ODI] were set at 100 for the purposes of analysing the results [n=number in brackets]:

Results show an improvement in the overall pain and disability. However, at two years patients still continued with some 65% of symptoms.

Laparoscopic assisted anterior spinal fusion with the BAK device is safe and reliable with advantages that include reduced operating time, blood loss, post-operative analgesia requirements and hospitalisation. However, the clinical outcome does not appear to give superior results to other implants and we question whether it use as a stand-alone device is sufficient and would recommend posterior stabilisation to confer improved mechanical stability.

Back pain may be related to abnormal segmental movement and suggested treatment is segmental fusion. Recent techniques using cages can achieve fusion rates of over 90% but the clinical results are no better. We hypothesise that the cages integrate fully to adjacent vertebrae taking all the load, producing abnormal stress patterns in the vertebrae producing pain.

In this study a simple FE model of a disc and its adjacent vertebral bodies was developed using ANSYS software. The dimensions of the model were based on those of a human lumbar disc. The normal disc was modelled as having nucleus with fluid properties (bulk modulus 1720 MPa). To model the degenerate disc, the material properties of the nucleus were changed to be the same as the annulus (Young’s modulus, E=5 Mpa; Poisson’s ratio, n=0.49). To model fusion of the disc, the nucleus was replaced with a simple representation of a one of three of the commonly used cages. In all the models the material properties of the cancellous bone (E = 100 MPa; n = 0.3) and the cortical bone (E=12000MPa;n=0.3) remained the same. The model was loaded axially with 1.5 kN.

The vertical and horizontal stress patterns around a loaded degenerate disc showed areas of increased loading in the endplate and cancellous bone. The inclusion of cages in the model showed high concentration of tensile and compressive stresses at the point of contact with the cages and in the cancellous bone of the vertebral bodies. The stress pattern showed more similarity to that of degenerate disc, than a normal one.

Fusion cages alter the pattern of stress distribution in the adjacent vertebral bodies from that of the normal disc. The excellent fusion rates of the cages are not mirrored by improvement in clinical results. It supports the concept that abnormal load transfer may be a more significant cause of back pain than abnormal movement.

Objective: To present early results of a new technique of dynamic stabilisation of the lumbo-sacral spine.

Design: Prospective study

Subjects: Between September 2000 and December 2001, 43 patients underwent posterior spinal stabilisation using the Dynamic Neutralisation System (DYNESYS) (Sulzer Medica).

Outcome Measures: Oswestry Disability indices, complications, visual analogue pain scores, patient satisfaction.

Results: The perceived indications were isolated degenerative disc disease (26), spondylolisthesis (8), degenerate adult scoliosis (4), failed Graf stabilisation (1), lumbar canal stenosis (3) and traumatic compression fracture (1).

Fixation was at one level in 14, two levels in 23, and three or four levels in 6 patients. Thirty-seven had Dyne-sys fixation alone and six had additional procedures at the same operation.

Complications included facet fracture (1), broken pedicle screw (1), apparent screw loosening (1) and discitis (1). At average follow-up of eight months (range 2–14 months), the average Oswestry disability score had fallen from 52 to 32 and the visual analogue pain score from 7.5 to 1.7. 65% of patients were pleased or better with their result.

Conclusions: The Dynesys system seems to be a safe alternative to conventional operative treatment for degenerative disorders of the lumbar spine without the need for rigid fusion. The anatomic re-stabilisation may allow the spinal segment to recover. The early results are encouraging. It is hoped that longer term follow-up will clarify the groups of patients who will benefit most from this procedure.

Posterior fixation of intervertebral discs is used to treat, and occasionally diagnose, discogenic pain since it is thought that it will reduce the internal loading of the discs in vitro. We measured the internal loading of ten intervertebral discs using stress profilometry under simulated physiological loads and then after posterior fixation. Partial discectomies were performed to simulate advanced disc degeneration and the sequence repeated.

Posterior fixation had very little effect on the magnitude of the loads acting on the disc and none when disc degeneration was simulated. It did, however, reduce bulging of the anterior annulus under combined bending and compression (p < 0.03). Recent experiments in vivo have shown that discogenic pain is associated with abnormal bulging of the annulus which suggests that the clinical benefit of fixation may be due to this.

1. A case of compression of the deep branch of the ulnar nerve is described.

2. Anatomical evidence is presented that the reason for the special liability of the deep branch to be compressed by ganglia in this region is its relationship to a ligamentous band which passes from the pisiform bone to the hamate superficial to the deep branch of the ulnar nerve.

3. This band, though constant, has not been well recognised.

1. A case of spontaneous posterior interosseous paresis is reported. It is suggested that the cause was replacement fibrosis secondary to local ischaemic damage from unremembered minor trauma.

2. In a patient with a posterior interosseous nerve paresis examination may reveal a space-occupying lesion near the elbow along the course of the nerve thus compressing it. Recovery may be expected after its removal. Consequently the nerve should be explored before resort to tendon transfers.