Lumbar spinal stenosis treatment with Aperius perclid interspinous system

PURPOSE

The purpose of this study is to report clinical outcome and imaging changes of percutaneous Aperius stand-alone implant in patients with degenerative lumbar spinal stenosis and neurogenic intermittent claudication, which did not respond to conservative treatment.

METHOD

Between January 2008 and July 2010, 37 patients (20 males and 17 females) with mean age of 64.3 years underwent surgery for the onset of claudicatio spinalis with Aperius PercLID interspinous device (Medtronic). In all patients, the diagnosis was: foraminal stenosis, in one case (2.7 %) it was associated to a degenerative anterior listhesis (I grade), in three cases (8.1 %) it was associated to an intraforaminal disc herniation. The mean follow-up was of 18 months (range 2-35 months). The patients were evaluated through the Oswestry disability index, Zurich Claudication Questionnaire (ZCQ), VAS scales. In all cases were obtained preoperative and in postoperative radiographs and magnetic resonance imaging.

RESULTS

The VAS score decreased significantly after surgery: the patients presented a mean VAS of seven preoperatively and two postoperatively (p < 0.001). The ZCQ score significantly decreased postoperatively, with an average reduction of 21.89 % (p < 0.001). The ODI score as well showed a significant reduction postoperatively of an average 26.09 % (p < 0.001).

CONCLUSION

Despite of the brief follow up, the preliminary results are encouraging, showing a significantly decrease of the disability parameters, a marked improvement of the function with the vanishing of the claudicatio spinalis and the following increase of the free interval during the walk. Aperius PercLID system seems to offer an alternative to the traditional decompression surgery.

Presence of NGF and its receptor TrkA in degenerative lumbar facet joint specimens

In a preliminary study, the recurrent presence of nervous terminations was demonstrated with optical microscopy in several slides of degenerative lumbar facet joints and surrounding soft tissues. The purpose of this study was to prove the presence of NGF (nerve growth factor) and its receptor TrkA (tyrosine kinase receptor) with immunofluorescence. The peri/articular tissues were harvested from the lumbar facet joints of ten patients surgically treated for degenerative diseases. There were seven females (one bilateral) and two males whose mean age at surgery was 72 years (range, 67-80 years). The affected levels were L3-L4 in two cases and L4-L5 in seven cases (one bilateral). All specimens were fixed in formalin, dehydrated and enclosed in paraffin. From each specimen, four slides were obtained. Two slides were employed for the search of NGF: one was treated with specific antibodies and marked with FITC (fluorescein isothiocyanate conjugated), and the second slide was for control purposes. It was exposed to FITC, but without prior exposure to the specific antibody. The same procedure was repeated to obtain on two more slides, to repeat the search for Trka with specific antibodies. All the slides were finally studied on a fluoromicroscope. The analysis of these specimens revealed the presence of the neurotrophin (NGF) and its own receptor (TrkA) in all cases: the immunohistochemical reaction between the specimens and the specific antibodies marked with FITC was seen under fluoromicroscopy, but in none of the control cases treated with FITC only. NGF is released by mastocytes, fibroblasts and other cell types involved in the inflammatory processes. The level of peripheral NGF is increased in inflammatory processes, while the administration of exogenous NGF has a hyperalgesic effect on rats and produces muscular pain in humans. Furthermore, NGF produces hypersensitization to heat stimulation in humans and mammals in general. There is considerable evidence showing that the system constituted by the NGF and its high-affinity receptor TrkA plays a fundamental role in the molecular processes underlying the main forms of "persistent" pain. This indicates a possible therapeutic area for the antibodies that could block the NGF/TrkA system, in order to modulate the frequency and the duration of the action potential of nociceptive neurons during chronic inflammation. This study demonstrated the presence of NGF and TrkA in specimens collected from degenerative facet joints, suggesting that specific molecules could be used in order to modulate chronic pain in patients with degenerative lumbar spine.

Factors Predisposing to Dislocation After Primary Total Hip Arthroplasty: A Multivariate Analysis of Risk Factors at 7 to 10 Years Follow-up

BACKGROUND

Dislocation of primary THA (total hip arthroplasty) is one of the most undesirable complications with an incidence ranging from 2% to 5%. Several risk factors are described, related to the patient, surgery, or prosthetic design. The aim of the study was to assess risk factors and their potential influence on dislocation.

MATERIALS AND METHODS

387 primary THA were performed between September 2005 to December 2008 at our institute (Varese, Italy) through a modified posterior-lateral approach. Clinical evaluation was based on range of motion (ROM) and Harris Hip Score; femoral offset, acetabular inclination, and anteversion were measured on plain radiograms. Data were analyzed by SPSS software (SPSS, Inc., Chicago, Illinois).

RESULTS

Excellent ROM and Harris Hip Scores were achieved in more than 95% of patients (p<0.05). The offset was restored in all patients. Most of the cases had their cup positioned in the "safe zone" (both inclination and anteversion). Six dislocations (1.87%) occurred: significant correlation was found between dislocation and preoperative diagnosis of femoral neck fracture.

CONCLUSIONS

THA dislocation rate appears not to be related to patient biometric parameters and prosthesis design. Femoral neck fracture is reported as the major risk factor for this complication, probably caused by higher preoperative activity and lesser compliance of the patient.