Purpose: We examined our preliminary results in a series of nine patients treated for thoracolumbar callus deformitis using a technique associating simultaneous anterior and posterior approaches and in situ contourning.

Material and methods: The series included seven women and two men, mean age 42 years operated on after January 2001. The patients had deformed callus after fractures (n=8) or spondylodiscitis (n=1). Surgical treatment was used initially for five of the fracture patients. The deformed callus involved the thoracolumbar junction in 56% of the patients. Mean follow-up was 14 months (6–22). The same surgical technique was used in all nine patients by two surgery teams. The patient was positioned in lateral decubitus. After posterior arthrectomy and anterior osteotomy, the correction was obtained by combined anterior distraction and lordosis contourning of the posterior material. An intercorporeal graft was encastrated anteriorly.

Results: Preoperative regional kyphosis was 30°. It was 4° postoperatively and 5° at last follow-up. Kyphosis improved in 87% of patients. There was no neurological aggravation. The main complication was posterior infection with aggravation of the regional kyphosis to 10° in one patient.

Discussion: Posterior or anterior spinal approach, alone or in combination have been proposed for callus deformitis of the spine. Results in the literature have shown moderate and incomplete correction of the kyphosis.

Conclusion: The proposed technique allows good reduction of the deformed callus with results that appear to persist with time.

Purpose: The biomechanical behaviour of the cervical spine was studied in vitro with an optoelectronic system in order to better understand its physiology.

Material: Twenty fresh cervical spines (occiput-D1) from fourteen men and six women, mean age 66.5 years, were sterilised with ß radiation (2.5 Mrad) and stored at −24°C then studied after slow thawing and excision of the paraspinal muscles.

Methods: Three-point reflecting markers were rapidly attached to each vertebral segment (4 or 5 vertebrae). The inferior vertebra was blocked. Six pure moment couples (2 N.m maximum, 10 increments) were applied in the three anatomic planes using a loading device lodged on the superior vertebra. Displacements were measured with the VICON 140 using a kinematic software.

Results: The three-dimensional behaviour curves of each functional unit (FU) were recorded for each solicitation to analyse the principal movement and coupled movements (maximum mobility, neutral zones, rigid zones, rigidity). Mean maximal flexion-extension movements were C0/C1= 28.7°; C1/C2 = 22.3°; C2/C3 = 7.3°; C3/C4 = 10.6°; C4/C5 = 13.8°; C5/C6 = 13.4°; C6/C7 = 10.8°; C7/T1 = 6.4°. Maximum overall lateral inclinations were: C0/C1= 8.7°; C1/C2 = 9.3°; C2/C3 = 8.7°; C3/C4 = 6.7°; C4/C5 = 10.5°; C5/C6 = 12.2°; C6/C7 = 8.6°; C7/T1 = 5.7°. Maximal overall axial rotations were: C0/C1= 11°; C1/C2 = 71°; C2/C3 = 9.5°; C3/C4 = 10.8°; C4/C5 = 12.3°; C5/C6 = 9°; C6/C7 = 5.6°; C7/T1 = 5.7°. All the FU exhibited flexion-extension movement. Lateral inclination coupled important controlateral rotation for C1/C2 and minimal ipsilateral rotation (< 10°) in the lower FU of the cervical spine. Axial rotation of the C1/T1 functional unit was coupled with homolateral rotation (< 10°).

Discussion: Our experimental protocol provided precision of < 1° and good reproducibility allowing simultaneous three-dimensional analysis of the spinal functional units. Making measurements without direct contact is particularly useful for the cervical spine. Our results are within the experimental corridor defined by Goel, Panjabi and Wen.

Conclusion: This work on a large number of functional units adds further support to data in the literature concerning the biomechanical behaviour of the cervical spine. Our protocol could be applied to analyse the impact of surgical procedures used for the cervical spine, particularly for the evaluation of new fixation systems or prostheses.

Purpose: There is growing concern about the effect of anterior fusion of the cervical spine on the adjacent levels. Long-term assessment is indispensable to understand the mechanisms involved in the degradation observed and to support the development of materials preserving discal mobility.

Material: Three hundred patients who underwent cervical arthrodesis were reviewed in 1996 forty months after the procedure for physical examination and an x-ray work-up including stress views. Cervical spine and radicular pain were assessed on a visual analogue scale.

Methods: A complete data set was available for 136 patients and a partial set for 34. Twenty-two patients only accepted a phone interview. The clinical outcomes in these three groups were not significantly different and the mean scores for these three groups were in the general average in 1996. Eight patients had died.

Results: Patients were divided into three groups by type of disease diagnosed preoperatively (trauma, degenerative spine, myelopathy). Mean follow-up was 102.5 months (range 84 – 180 months).

Trauma: Among the 42 patient reviewed again in 2001, mean deterioration in the subjacent segment increased from 21% in 1996 to 69% in 2001. Deterioration of the supraja-cent segment increased from 26% to 47.6%. Cervical pain remained moderate (20/100 in 1996 and 27/100 in 2001). Degenerative spine (root compression requiring simple discectomy or with arthrodesis or single-level corporectomy): Among the 42 patients reviewed again in 2001, deterioration of the subjacent segment increased from 57% in 1996 to 89% in 2001. Deterioration of the suprajacent segment increased from 22% to 41%. Cervical pain increased from 14/100 in 1996 to 41/100 in 2001.

Myelopathy: Among the 52 patients reviewed again in 2001, deterioration of the subjacent segment increased from 54% in 1996 to 81% in 2001 when there had been one or two corporectomies and from 40% to 70% beyond two. Deterioration of the suprajacent segment increased from 26% to 50%. Cervical pain remained moderate (18/100 in 1996 and 23/100 in 2001).

Conclusion: Although a statistical analysis was not possible because of the small number of patients and the large percentage lost to follow-up, these results confirm that fusion of the cervical spine accelerates the degradation of adjacent levels. Longer follow-up demonstrates that the trauma group “catches up” with the degenerative group.

Use of mobile materials should enable differentiating between effects related to the degenerative process and those induced by the arthrodesis.

Purpose: Access to the cervicothoracic junction is difficult both via a posterior and via an anterior approach. Tumour localisations or more rarely trauma however require access. Using the posterior approach, anterior decompression is limited by the narrow access and the vulnerability of the cord. Anterior reconstruction is impossible. Using the pure anterior approach, fixation and decompression of the caudal component is limited. Preoperative MRI shows the respective position of the manubrium sternal and the diseased vertebra, allowing a clear surgical strategy. To avoid sternotomy or even partial cleidectomy, both causes of postoperative pain and complications, we developed a medial sternal resection maintaining the stability of the sternoclavicular joints and allowing spinal decompression by corporectomy to T3 and fixation to T4.

Material and methods: A left anterolateral cervical approach was used to avoid injury to the recurrent nerve. This is a classical cervical approach generally used for access to C7-T1. It is prolonged caudally a few centimetres on the mid line to reach the anterior aspect of the sternum. After section of the sternohyoid, sternothyroid and scapulohyoid muscles, the three upper centimetres of the sternum are resected with a microdrill over a width of two centimetres. This give direct access to the anterior walls of T3 and T4. The lower limit of the exposure is described by the aortic arch (except in patients with severe kyphosis). The left brachiocephalic venous trunk is the crucial element situated just horizontally behind the sternum and protected by fat and fibrous tissue. It is important to release this trunk precautiously because injury at this level is difficult to suture and would require ligature (this is still possible if necessary but would lead to oedema of the left arm by defective drainage). After releasing the vein, the resection of the posterior wall of the sternum is completed with a Kerrison gouge. This gives a U-shaped groove that does not destabilise the sternoclavicular articulations and allows retraction of the vessels to expose the vertebral bodies. Screw fixation of T4 is possible, generally with slightly descending screws. The classical closure method is used.

Results: We have operated 13 patients with tumours or fractures using this approach (five T4, seven T3, one T2). Corporectomy was performed above T4. This approach did not lead to any direct complications. Postoperative pain was considered to be less than with sternotomy or cleidectomy, approaches we have now abandoned. Use of the endoscope improves visibility but the incision cannot be smaller because of the axe required for screwing. The important features of this method are the correct analysis of the preoperative relation between the target vertebra and the manubrium sternal and the dissection of the left brachiocephalic venous trunk.

Purpose: After cementing, various changes are observed in femoral bone resulting from various factors (ageing process, stress forces, granuloma…). The purpose of this work was to examine the radiological expression of these changes a mean 12 years after prosthesis implantation.

Material and methods: Charnley-Kerboull total hip arthroplasty was performed in 304 patients (338 hips) between January 1st, 1984 and December 31st, 1986. Mean age of the population was 65.5 years. Most of the patients had degenerative hip disease (81.4%). Among these 304 patients, 108 had died and 56 were lost to follow-up, giving 174 patients retained for analysis at a maximum follow-up of 16 years (mean 12 years). Noble and Nordin scores were recorded before surgery and during follow-up as were the cortical and cement thicknesses in the seven zones described by Gruen.

Results: The actuarial curve, calculated for the 338 hips showed 95.1% survival at 12 years (taking into account all revisions irrespective of the cause). Femoral stem survival was 97.1±2% taking certain or probable loosening as the endpoint. Several categories or radiological changes were observed: – femoral defects (18%) correlated with cup wear; – progressive widening of the medullary canal without loosening and a mean femoral score moving from 55.7 to 52.16 (p< 0.01) especially in thin women and for wide-mouthed femurs; – cortical thickening near the tip (57%) more frequently for greater distal filling; – stress shielding especially in women (p< 0.001) with a low initial score for the femur (p< 0.0006) and with greater distal filling.

Conclusion: Like Kerboull, we tried to achieve primary stem stability before cementing. Cementing results were good (97% at 12 years), but detailed radiographic analysis demonstrated that cortical thinning remained in zone 7, especially when the primary stability was achieved in the distal portion of the femur (high preoperative Noble index). Variations in the metaphyseal-diaphyseal ratio require adaptating the form of the stem to be cemented in order to achieve better filling and avoid primary stability mainly in the distal portion.