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.

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.

The sublabral foramen: does it affect stress distribution on the anterior glenoid?

Even though it is believed that a sublabral foramen (SF) requires no treatment, no objective data are available to establish whether this condition bears a relationship to anterior-inferior glenohumeral instability. Therefore, the influence on glenoid subchondral bone mineralization of an isolated SF was investigated, because the individual distribution of subchondral bone mineralization may be used as an indirect parameter for long-term stress distribution of joints. Two age- and side-matched groups of healthy glenohumeral specimens with SF (n = 10, aged 37-85 years) and without SF (n = 10, aged 36-86 years) were examined by computed tomography osteoabsorptiometry. As variables for comparison, the anterior and posterior density maxima on the glenoid were measured in a standardized manner. No shift of the anterior density maximum [p(x1) = 0.353/p(y1) = 0.739] was found between both groups, which is in contrast to anterior glenohumeral instability. This indicates a long-term stress distribution in SF shoulders comparable to that in non-SF shoulders. The data suggest that an isolated SF is probably not disproportionately related to glenohumeral instability and support the general assumption that surgical treatment of SF is not required.

Substance P and prostaglandin E2 release after shock wave application to the rabbit femur.

The biologic action of extracorporeal shock wave application on the musculoskeletal system is poorly understood. To prove the hypothesis that alterations of tissue concentrations of substance P and prostaglandin E(2) are involved in the biologic action of shock waves, extracorporeal shock waves with energy flux density of 0.9 mJ/mm2 (1500 pulses at 1/second) were applied in vivo to the distal femur of rabbits. The concentrations of substance P and prostaglandin E(2) eluted from the periosteum of the femur were measured. Compared with the untreated contralateral hindlimbs, substance P release from the periosteum from the femur was increased 6 hours and 24 hours after extracorporeal shock wave application, but was decreased 6 weeks after extracorporeal shock wave application. By contrast, extracorporeal shock wave application did not result in altered prostaglandin E(2) release from the periosteum from the femur. Remarkably, there was a close relationship between the time course of substance P release found here, and the well-known clinical time course of initial pain occurrence and subsequent pain relief after extracorporeal shock wave application to tendon diseases. Accordingly, substance P might be involved in the biologic action of extracorporeal shock wave application on tissue of the musculoskeletal system. This is the first study providing insights into the molecular mechanisms of extracorporeal shock wave application to the musculoskeletal system.

Influence of minimally invasive surgery on implant positioning and the functional outcome for medial unicompartmental knee arthroplasty.

We describe postoperative functional outcome and accuracy of implant position in 38 cases after unicompartmental knee arthroplasty with the Oxford knee prosthesis with a standard open approach compared with 30 cases with a minimally invasive approach. Patients with the minimally invasive approach had significantly better functional results, with an average Hospital for Special Surgery scores of 92 (range, 81-98) compared with 78 (range, 24-99). Range of motion 1 year postoperatively was better in the minimally invasive group (113 degrees vs 107 degrees ), but the results were not statistically significant. The number of patients with extension lag was significantly higher after the open approach. The minimal invasive approach had no negative effect on positioning of the prosthesis. In our opinion, minimally invasive implantation is the method of choice for the treatment of anteromedial osteoarthritis by unicompartmental knee arthroplasty.

Low accuracy of stem implantation in THR using the CASPAR-system: anteversion measurements in 10 hips.

We studied 10 patients by means of pre- and postoperative CT who underwent computer-assisted total hip replacement using the CASPAR-system (OrthoMaquet GmbH, Rastatt, Germany). The anteversion angles of the stem and translational deviations measured after surgery were compared to the preoperatively planned ones as a quality control. We found an average difference of 7.8 degrees (SD 6.3 degrees; 95% CI 3.3 degrees-12.3 degrees) in the angles and an average difference of 1.8 (SD 1.7; 95% CI 0.6-3.0) mm and 1.2 (SD 1.4: 95% CI 0.25-2.2), respectively, in the medial and lateral deviation. In conclusion, we could not confirm the same accuracy of implant position as that claimed by the manufacturer.

Anterior shoulder instability modifies glenoid subchondral bone density.

Subchondral bone mineralization is used as a morphologic marker for individual stress distribution of joints and therefore may help to distinguish variations of glenohumeral contact. Therefore, an in vivo analysis was done to evaluate glenoid stress distribution in anterior glenohumeral instability by computed tomography osteoabsorptiometry. Patients with recurrent anterior glenohumeral dislocation, seven of posttraumatic and six of atraumatic origin, and an intact rotator cuff were grouped retrospectively and compared with healthy, age-matched shoulder specimens from cadavers (n = 13). Glenoid subchondral bone mineralization, including those in all patients with anterior glenohumeral instability, indicated a more anterior and inferior stress distribution compared with stable shoulders. The position of the anterior glenoid density maximum had shifted anteriorly and inferiorly whereas the position of the posterior maximum had shifted anteriorly. Analyzing results on the basis of cause, in posttraumatic instabilities, the shift of the anterior maximum mainly was anterior and in atraumatic instabilities, it mainly was inferior. Individual glenoid stress distribution in anterior glenohumeral instability can be assessed objectively by computed tomography osteoabsorptiometry. The shift of the density maxima corresponded with anterior and inferior directions of humeral head displacement, whereas the degree of changes varied according to the cause of glenohumeral instability.

Dose-related effects of extracorporeal shock waves on rabbit quadriceps tendon integrity.

BACKGROUND: Recently, morphological signs of damage were reported in rabbit Achilles tendon following extracorporeal shock wave application (ESWA) with an energy flux density (EFD) of 0.6 mJ/mm(2). However, it is unknown whether or not the same can be found after ESWA to other tendons such as the quadriceps tendon. METHODS: We investigated the effects of ESWA in vivo on rabbit quadriceps tendon. Animals received 1,500 SW pulses each of different EFD ranging between 0.0 and 1.2 mJ/mm(2) on either the left or right quadriceps tendon. ESWA effects were investigated by histopathological examination. RESULTS: ESWA with EFD of 0.5 mJ/mm(2) upwards resulted in edema within the paratenon. ESWA with EFD of 1.2 mJ/mm(2) resulted in various morphological signs of damage within the tendon and paratenon. CONCLUSIONS: We conclude that ESWA to the quadriceps tendon in clinical experimental use should be restricted to EFD less than 0.5 mJ/mm(2).

Malignant lymphoma of bone.

Malignant lymphoma of bone is rare. In many cases, its diagnosis is delayed because of unspecific clinical signs and equivocal radiographs. Therapy in general is multimodal, including surgery and radio- and chemotherapy. Our objective was to demonstrate the clinical and radiological aspects of the lesion to optimize diagnostic approaches and to evaluate treatment and prognostic factors. Thirty-six patients with malignant lymphoma of bone who were surgically treated over a 15-year-period were retrospectively reviewed. Seventeen of them showed a singular bone non-Hodgkin's lymphoma (NHL) which was classified as primary lymphoma of the bone (PLB). In 13 cases, dissemination of the disease with multiple bone or visceral involvement was apparent (dNHL). Six patients suffered from bone involvement due to Hodgkin's disease (HD). Surgical treatment was indicated for diagnostic reasons or complications due to the disease. Radiation and chemotherapy were part of the oncological treatment. The patients' mean age was 57 years. The main symptom in malignant bone lymphoma in 33 patients was pain, with an average duration of 8 months. In the secondary cases, bone involvement appeared on average 57 months after the initial diagnosis. An osteolytic pattern was seen in 58% of the lesions. Soft-tissue involvement was seen in 71% of cases (PLB 80%, dNHL 73%, HD 40%) and was the primary diagnostic sign associated with this disease. The 5-year survival rate was 61% (PLB 88%, dNHL 38%, HD 50%). Multiple vs solitary bone involvement was the most significant factor in the prognosis. Extraskeletal involvement significantly decreased survival. No correlation was found between gender, age, location, or histological subtypes and survival. Bone involvement in NHL appears late in the extraskeletal disease. The clinical appearance is nonspecific, and the delay between the onset of symptoms and diagnosis is often long. One of the major radiologic signs is the existence of a soft-tissue tumor surrounding the bone with little or no bone involvement on plain films. Treatment generally is conservative, based on the stage of the disease. Local radiation with or without systemic chemotherapy should be used. The long-term survival is favorable, but dependent on the stage of the disease and the amount of bone involvement.

Multiple myeloma: surgery of the spine: retrospective analysis of 27 patients.

STUDY DESIGN: The authors report on the clinical course of 27 consecutive patients surgically treated for solitary or multiple myeloma of the spine. OBJECTIVES: To evaluate the complications, neurologic function, life quality, and survival after decompression of the spinal cord and stabilization of the spinal column in cases of conventionally untreatable pain, neurologic impairment, or spinal instability. SUMMARY OF BACKGROUND DATA: The clinical outcome in patients surgically treated for multiple myeloma of the spine has not been intensively studied. Because patients with myeloma often live longer than patients with bone metastases from other malignancies, it is important that these patients be examined and treated with methods specific to their needs and not only with those typically used for patients with metastatic disease. METHODS: The 27 patients had undergone the following surgical procedures: two dorsal decompressions, seven dorsal decompressions and stabilizations, 15 ventral decompressions and stabilizations, and three ventral and dorsal decompressions and stabilizations. Quality of life was measured by the Karnofsky Index, neurologic impairment according to Frankel, and survival by the Kaplan-Meier method. RESULTS: Life quality improved from 48% before surgery to 59% 1 month after surgery and 73% in 24 survivors after the first year. Comparison of their presurgical scores with the scores obtained 1 month after surgery revealed that 18 patients had improved, five patients stayed the same, and four patients declined. After 1 year the scores of all 24 surviving patients had improved from their presurgical levels. In the 21 patients with unimpaired preoperative neurologic function, one patient developed a paraparesis as a complication of surgery, while 20 remained unimpaired until death or 1 year after treatment. All six patients with neurologic deficits improved, two of them to normal function. Pain relief was evident in 26 cases. The mean length of postoperative survival was 49.7 months. Local tumor recurrence occurred in three of 27 patients (11.1%). CONCLUSION: The surgical treatment of myeloma of the spine seems to be an effective method of treatment with respect to neurologic function and life quality in selected cases.

Surgical treatment of bone metastases in patients with breast cancer.

In this retrospective study, the effect of surgical therapy on a series of 70 patients with breast cancer who were surgically treated for metastasis of the bone was evaluated. At presentation, 19 patients had one osseous lesion, 19 patients had multiple bone lesions, and 32 patients had additional visceral involvement. The surgical procedures included 60 palliative procedures, six radical resections, and four biopsies. In 14 surviving patients, the mean observation period was 35.6 +/- 40.1 months. Of the six patients with radically resected solitary bone lesions, five patients had systemic progression of the disease develop. Of the 19 patients with presumably solitary bone lesions, five currently are free of tumor. Of the 19 patients with multiple bone lesions and initially no visceral tumor spread, only two are alive. Of the 32 patients with additional visceral metastases at surgery, four are alive with the disease. For the entire group, the survival rate was 59% after 1 year, 36% after 2 years, 13% after 5 years, and 7% after 10 years. The only two independent factors that were associated with survival were the extent of the disease and the duration of symptoms from bone metastasis. These findings suggest that in orthopaedic surgery in patients with bone metastases secondary to breast cancer, wide resection is not likely to be necessary. Patients with solitary bone lesions have a 39% chance of living 5 years.