Complications following kyphoplasty in unstable osteoporotic vertebral body fractures. A guide to correct fracture analysis.

The possibilities offered by kyphoplasty in the treatment of osteoporotic vertebral fractures have been widely described. Kyphoplasty is technically not very demanding, it can be easily learned and it is minimally invasive when compared to open surgical fracture treatment. Like many other simple surgical methods, it has spread rapidly and as a consequence of the above factors combined with its good reimbursement in many countries, it has experienced a widening in the indications for which it is being employed. The intial purpose of kyphoplasty was pain relief based on vertebral body stabilisation combined with restoration of vertebral body height. An increasingly uncritical use of the method can be observed and as a consequence, an increase in serious complications. During recent years, spinal surgery departments have received an increasing number of patients with serious complications following kyphoplasty, requiring major reconstructive spinal surgery. On the basis of 12 cases treated over the past 36 months, we aim to provide guidelines for the indications of the kyphoplasty procedure.

Thermoelastic stress analysis to validate tibial fixation technique in total ankle prostheses - a pilot study.

BACKGROUND: Recent literature has shown a persistently high rate of aseptic loosening of the tibial component in total ankle prostheses. METHODS: We analyzed the interface between the tibial bone and tibial component with a thermoelastic stress analysis to demonstrate load transmission onto the distal tibia. In this regard, we used two established ankle prostheses, which were implanted in two human cadaveric and in two third-generation composite tibia bones (Sawbones®, Sweden). Subsequently, the bones were attached to a hydropulser and a sinusoidal load of 700 N was applied. RESULTS: Both prostheses had an inhomogeneous load transmission onto the distal tibia. Instead of distributing load equally to the subarticular bone, forces were focused around the bolting stem, accumulating as stress maxima with forces up to 90 MPa. Furthermore, we were able to demonstrate load transmission into the metaphysis of the bone. CONCLUSION: As demonstrated in this study, anchoring systems with stems used in all established total ankle prostheses lead to an inhomogeneous load transmission onto the distal tibia, and furthermore, to a distribution of load into the weaker metaphyseal bone. For these reasons, we favor a prosthetic design with minimal bone resection and without any stem or stem-like anchoring system, which facilitates a homogeneous load transmission onto the distal tibia. Thermoelastic stress analysis proved to be a fast and easy-to-perform method to visualize load transmission.

Medial branch blocks versus pericapsular blocks in selecting patients for percutaneous cryodenervation of lumbar facet joints.

BACKGROUND AND OBJECTIVES: At many institutions, it is not practically feasible to perform a series of controlled or placebo-controlled medial branch blocks on several facet joints in order to select patients for facet joint rhizotomy. As for uncontrolled blocks, there is no proof that medial branch blocks are superior to other types of blocks. This study was performed to compare medial branch blocks to simple pericapsular blocks for the selection of patients for lumbar facet joint cryodenervation. METHODS: Patient selection was based on history, imaging, and physical examination. Diagnostic blocks were either medial branch blocks or pericapsular blocks. Percutaneous medial branch cryodenervation was performed by use of a Lloyd Neurostat 2000. Outcome parameters were low back pain (visual analog scale [VAS]), limitation of activity (Macnab), and overall satisfaction. A total of 26 patients were recruited, 13 for each group. Follow-up was 6 months. RESULTS: Patients who had been selected by medial branch blocks had better pain relief than did patients who had been diagnosed by use of pericapsular blocks. At 6 weeks and at 3 months after treatment, these results reached statistical significance (VAS 2.2 v 4.2, P < .05). CONCLUSIONS: Our results suggest that uncontrolled medial branch blocks are superior to pericapsular blocks in selecting patients for facet joint cryodenervation, but both blocks work. If serial controlled blocks cannot be used, lumbar facet joint pain remains a diagnostic dilemma.

Posterior lumbar interbody fusion (PLIF) with cages and local bone graft in the treatment of spinal stenosis.

Posterior lumbar interbody fusion (PLIF) implants are increasingly being used for 360 degrees fusion after decompression of lumbar spinal stenosis combined with degenerative instability. Both titanium and PEEK (PolyEtherEtherKetone) implants are commonly used. Assessing the clinical and radiological results as well as typical complications, such as migration of the cages, is important. In addition, questions such as which radiological parameters can be used to assess successful fusion, and whether the exclusive use of local bone graft is sufficient, are frequently debated. We prospectively evaluated 30 patients after PLIF instrumentation for degenerative lumbar spinal canal stenosis, over a course of 42 months. In all cases, titanium cages and local bone graft were used for spondylodesis. The follow-up protocol of these 30 cases included standardised clinical and radiological evaluation at 3, 6, 12 and 42 months after surgery. Overall satisfactory results were achieved. With one exception, a stable result was achieved with restoration of the intervertebral space in the anterior column. After 42 months of follow-up in most cases, a radiologically visible loss of disc space height can be demonstrated. Clinically relevant migration of the cage in the dorsal direction was detected in one case. Based on our experience, posterior lumbar interbody fusion (PLIF) can be recommended for the treatment of monosegmental and bisegmental spinal stenosis, with or without segmental instability. Postoperative evaluation is mainly based on clinical parameters since the titanium implant affects the diagnostic value of imaging studies and is responsible for artefacts. The results observed in our group of patients suggest that local autologous bone graft procured from the posterior elements after decompression is an adequate material for bone grafting in this procedure.

A prospective morphological study of facet joint integrity following intervertebral disc replacement with the CHARITE Artificial Disc.

In degenerative disc disease (DDD), increased loading in the posterior column increases facet joint subchondral bone density and may lead to facet joint degeneration. While spinal fusion is commonly used to treat patients with symptomatic DDD, increased stress at the levels adjacent to fusion may accelerate facet joint and adjacent segment degeneration. Artificial disc replacements have been developed as an alternative to fusion. In this prospective study, the effects of disc replacement with the CHARITE Artificial Disc on facet joint loading and integrity were evaluated. Thirteen patients aged <50 years with symptomatic DDD were recruited. Computed tomography (CT) osteoabsorptiometry was performed prior to the implantation of the CHARITE Artificial Disc and six months after. With this technique, increases or decreases in facet joint loading and integrity are indicated by corresponding changes in subchondral bone density. Changes in the distribution of load alter the distribution of the areas of maximum bone density. Clinical outcome was also assessed at pre-operative and 6 and 12 month post-operative visits using the Visual Analogue Scale back and leg pain scores, the Oswestry Disability Index and the Short Form-36 (SF-36) questionnaire. The height of the intervertebral space at the operated level was monitored by lateral X-ray. Subchondral bone density was evaluated in the facet joints of all 13 patients at the operated level, 12 patients at the level above the operated segment, and five patients at the level below the operated segment. Quantitative measurements revealed no significant increases (> or =3%) in subchondral bone density of the facet joints at any level in any patient. Significant decreases (> or =3%) in subchondral bone density were measured at the operated level in 10/13 patients, at the level above the operated segment in 6/12 patients, and at the level below the operated segment in 3/5 patients. There were no changes in the distribution of the areas of maximum bone density in any of the studied facet joints at 6 months compared with pre-operative measurements. Clinical outcome scores were improved at 6 and 12 months compared with baseline. The mean intervertebral space height at the operated level was increased following implantation of the CHARITE Artificial Disc and was 1.8 times greater than the pre-operative height at both 6 and 12 months. In this study, replacement of degenerated intervertebral discs with the CHARITE Artificial Disc was not associated with increased loading of the facet joints at the operated or adjacent levels. Decreases in subchondral bone density may indicate reduced loading in the posterior column following disc replacement compared with loading in the pre-operative degenerated spine. Further study is required to establish the baseline for healthy subchondral bone density and to compare this baseline with long-term measurements in patients undergoing disc replacement.

Operative treatment for degenerative lumbar spinal canal stenosis.

The authors have made a retrospective study of a cohort of patients who underwent surgery for spinal stenosis. A total of 85 patients were surgically treated for spinal stenosis between 1993 and 1997, and 79 patients were available for re-evaluation. The average time of follow-up was 79 months. Twenty patients with monosegmental stenosis underwent fenestration and undercutting, 16 patients had a hemilaminectomy or laminectomy and 43 patients had an instrumented fusion after decompression. The severity of the clinical complaints, the degree of stenosis and the extent of the instability determined the method of operation used. Results were more variable when extensive decompression (hemilaminectomy or more) was needed and segmental stability was reduced by resection of large portions of the facet joints. Instability clearly worsened the results. The overall results clearly show that limited decompression is an ideal operative method, provided the indication is correct. Fusion cannot be avoided if segmental instability is present. This retrospective study shows that satisfactory long-term results can be achieved in lumbar spinal stenosis with surgery adapted to the degree of instability and the degree of stenosis.

Medial ankle instability: an exploratory, prospective study of fifty-two cases.

BACKGROUND: Very little objective data are available regarding medial ankle instability. HYPOTHESIS: Several structures contribute to the stabilization of the medial ankle, and, in the case of injury, they are not involved in a uniform way. STUDY DESIGN: Explorative, prospective case series. METHODS: Fifty-one patients (52 ankles; males 27, females 25; age 36.4 [16 to 60] years) were surgically treated because of medial ankle instability. All clinical findings and structural changes, as found by arthroscopy and surgical exploration, were compared with the clinical diagnosis and then addressed for surgical reconstruction. RESULTS: Pain in the medial gutter was noted in all ankles (100%). Arthroscopy verified a clinically expected additional lateral instability in 40 ankles (77%). At 4.43 years (2 to 6.5 years) after surgical reconstruction, the clinical result was considered to be good/excellent in 46 cases (90%), fair in 4 cases (8%), and poor in 1 case (2%). CONCLUSION: The clinical characteristics of medial ankle instability are a feeling of giving way, pain on the medial gutter of the ankle, and a valgus and pronation deformity of the foot that can typically be actively corrected by the posterior tibial muscle. Arthroscopy was shown to be a very helpful diagnostic tool in verifying medial instability.