Biomedical subjects

K Blanke

Publications and source records attributed to K Blanke.

26 records · Page 2Linked to original sources

PubMed1995

Anterior fresh frozen structural allografts in the thoracic and lumbar spine. Do they work if combined with posterior fusion and instrumentation in adult patients with kyphosis or anterior column defects?

STUDY DESIGN: This was a prospective study of 24 adult patients with kyphosis or anterior column spinal defects treated with anterior fresh frozen allograft for anterior column defects and posterior instrumentation and autogenous grafting. OBJECTIVES: The objectives of the study were to assess the effectiveness of the anterior allograft in maintaining sagittal correction and to assess anterior incorporation. SUMMARY OF BACKGROUND DATA: Twenty-four patients were followed for a minimum of 2 years (range, 2 + 0-5 + 4 years). METHODS: Upright radiographs were analyzed before surgery, immediately after surgery, and at the final follow-up examination to assess success of anterior fusion and maintenance of correction. A strict four-point grading system was used. Two independent observers analyzed the radiographic results. RESULTS: Only two patients showed some collapse of their anterior allograft. The other 22 patients maintained correction, attaining a Grade I or Grade II fusion. Semiconstrained instrumentation ws used posteriorly in the two patients who had graft collapse. CONCLUSIONS: Anterior structural allograft worked effectively to maintain correction of kyphosis if combined with posterior instrumentation and autogenous grafting. Rigid forms of posterior instrumentation were preferred.

Adult↗

PubMed1994

Posterior spinal fusion supplemented with only allograft bone in paralytic scoliosis. Does it work?

STUDY DESIGN: The authors prospectively evaluated 40 patients with paralytic scoliosis treated from 1985 to 1990 with bilateral posterior segmental instrumentation, facet fusions, local bone graft, and allograft (mostly fresh frozen) bone supplementation only. OBJECTIVES: The authors report the fusion results for these patients, and any complications referable to the use of bank bone. SUMMARY OF BACKGROUND DATA: Acceptable correction was obtained and maintained in the coronal and sagittal planes for all but two patients (the third patient with a pseudarthrosis had not lost correction). The definite pseudarthrosis rate was 7.5%. One patient had a deep wound infection. METHODS: The radiographs were graded as definitely solid, definitely a pseudarthrosis, or no instrumentation failure but difficult to visualize the whole fusion mass. The patients selected for fusion without autogenous harvesting were especially frail and had reduced pulmonary and nutritional reserve. Follow-up ranged from 2 + 2 years to 7 + 6 years, with an average of 3 + 9 years. RESULTS: In the 40 surgical patients, there were three known pseudarthroses. In 28 patients, there was a definite fusion. In the remaining nine patients (five with flaccid disease, four with spastic disease), the quality of their bone precluded definitive determination, but there was no obvious instrumentation failure or loss of correction. CONCLUSION: This study suggests that allograft bone graft is a suitable substitute for autogenous bone graft harvesting in select patients with paralysis in whom autogenous harvesting is not feasible.

Adolescent↗

PubMed1994

Recognition and treatment of the proximal thoracic curve in adolescent idiopathic scoliosis treated with Cotrel-Dubousset instrumentation.

STUDY DESIGN: A retrospective radiographic and clinical review of a consecutive series of patients with adolescent idiopathic scoliosis (AIS) instrumented/fused with Cotrel-Dubousset instrumentation (CDI) was undertaken. OBJECTIVE: The authors determined criteria when the upper thoracic curve should be instrumented/fused in AIS treated with CDI and assessed the results of surgical treatment. SUMMARY OF BACKGROUND DATA: Failure to recognize and include the upper left thoracic curve in the instrumentation/fusion of a lower right thoracic idiopathic scoliosis may produce shoulder imbalance and coronal decompensation. Patients with an elevated left shoulder clinically or a positive T1 tilt radiographically usually require instrumentation/fusion of the proximal thoracic curve. However, the upper left thoracic curve may be structural and require inclusion in the instrumentation/fusion when the shoulders clinically are level or even if the right shoulder is elevated preoperatively when using CDI. METHODS: The authors compared 27 patients with AIS with structural upper thoracic curves that were instrumented with CDI to T2 (Group I) to 27 patients with King Type III curves treated with CDI that did not have the upper thoracic curve instrumented/fused (Group II). RESULTS: The distinguishing Group I preoperative criteria indicating a structural upper thoracic curve included a proximal thoracic curve greater than 30 degrees that corrected to no better than 20 degrees on sidebending; > or = Grade I rotation or > or = 1 cm translation present at the apex of this curve; any elevation of the left shoulder or tilt of T1 into the concavity of the upper thoracic curve; or when the transitional vertebra between the two curves is at T6 or below. CONCLUSIONS: When these aforementioned criteria are present and surgical correction with CDI is planned, we recommend extending the instrumentation up to T2 to produce level shoulders and maintain coronal balance.

Adolescent↗

PubMed1994

Preoperative spinal canal investigation in adolescent idiopathic scoliosis curves > or = 70 degrees.

STUDY DESIGN: This is a prospective evaluation of a consecutive series of patients with adolescent idiopathic scoliosis (AIS) with curves > or = 70 degrees. OBJECTIVE: The authors investigated the possibility that large curve size may constitute an atypical presentation of idiopathic scoliosis suggestive of underlying neurologic pathology, which would warrant preoperative investigation. SUMMARY OF BACKGROUND DATA: The potential for intraspinal pathology to cause scoliosis is well accepted. The incidence of spinal canal abnormalities in congenital or atypical scoliosis may be as high as 30-60%. Identification of clinical neurologic deficits, congenital abnormalities, or atypical features of scoliosis are often helpful in identifying the subpopulation of scoliosis patients at risk for spinal canal pathology. METHODS: Thirty-three consecutive patients with large (> or = 70 degrees) adolescent idiopathic scoliosis (AIS) and without evidence of neurologic or congenital abnormalities, were evaluated with either computed tomography/myelogram (n = 3) or magnetic resonance imaging (n = 30) to assess the entire spinal canal. RESULTS: None of the studies revealed any pathology of the neuraxis, and all 33 patients were treated with surgery without any neurologic sequelae. CONCLUSIONS: Preoperative investigation of the central neuraxis is not mandatory in large (> or = 70 degrees) but otherwise typical AIS curves. These large curves do not appear to suggest associated spinal canal anomalies.

Adolescent↗

PubMed1993

Ability of Cotrel-Dubousset instrumentation to preserve distal lumbar motion segments in adolescent idiopathic scoliosis.

Between 1985 and 1990, 44 patients with adolescent idiopathic scoliosis were treated with Cotrel-Dubousset instrumentation when Harrington instrumentation would have extended into the distal lumbar spine (L3, L4, or L5) for these curve patterns. Twenty-four of these 44 (group I) patients had one distal fusion level preserved using Cotrel-Dubousset instrumentation, whereas the other 20 patients (group II) were instrumented/fused with Cotrel-Dubousset instrumentation to the expected Harrington instrumentation level in the lower lumbar spine. All patients have a minimum 2-year follow-up, and the average follow-up is 39 months (range 24-74). The characteristics of the group I curves that allowed us to stop the instrumentation a level short included minimal rotation and tilt of the anticipated lowest instrumented vertebra, overall coronal curve flexibility, and nonstructural components to the lumbosacral region of the spine. There were no major differences between these two groups when comparing postoperative coronal and sagittal balance parameters at the most recent follow-up. In select cases, dependent on the preoperative criteria to be discussed, Cotrel-Dubousset instrumentation (vs. traditional Harrington instrumentation) does allow distal lumbar fusion levels to be saved while maintaining acceptable coronal and sagittal balance.

Adolescent↗

PubMed1992

Analysis of pulmonary function and axis rotation in adolescent and young adult idiopathic scoliosis patients treated with Cotrel-Dubousset instrumentation.

Forty-eight patients with idiopathic scoliosis underwent posterior spinal fusion with Cotrel-Dubousset instrumentation (CDI). Each patient was given preoperative and postoperative pulmonary function tests (PFTs). Pulmonary volume improved a mean 0.40 L (16%), and pulmonary flow improved a mean 0.33 L (15%). Differences between preoperative and postoperative PFT values were shown to be statistically significant and correlated well with coronal side-bending correction. Twenty patients had preoperative and postoperative CT scans through the apical vertebra. Vertebral rotation was assessed on CT scan by the method of Aaro and Dahlborn (1,2). At the apex, the mean percentage improvements in the longitudinal axis rotation relative to the midline (16%) and to the sagittal plane (10%), the rib hump index (8%), and the kyphosis-lordosis index (0%) were minimal. Radiographically, the 66% mean improvement in apical vertebral translation was more substantial and consistent than the 10% mean improvement in apical vertebral rotation. Therefore, at the apex the CDI "derotation maneuver" may be more of a "translational maneuver."

Adolescent↗

PubMed1992

Preventing decompensation in King type II curves treated with Cotrel-Dubousset instrumentation. Strict guidelines for selective thoracic fusion.

Between 1985 and 1988, 50 adolescent idiopathic scoliosis patients with either King Type II (n = 19) or III (n = 31) curves were treated with Cotrel-Dubousset instrumentation and had a minimum of 2-year follow-up. Five of these patients had early postoperative decompensation, and have provided important lessons for the future prevention and treatment of these imbalances. Most problematic was distinguishing between King Type II and double major curve patterns. Proper identification of King Type II curves, which may be successfully treated with selective thoracic fusion, requires careful analysis of the standing preoperative coronal radiograph as well as the side benders. Thus, we now define Type II curves based on the differential between the thoracic and lumbar curve magnitude, apical vertebral deviation from the midline, and apical vertebral rotation on the standing coronal radiograph in addition to a positive flexibility index.

Adolescent↗

PubMed1992

Cotrel-Dubousset instrumentation for adolescent idiopathic scoliosis.

We evaluated the results of segmental fixation of the spine with Cotrel-Dubousset instrumentation in ninety-five patients who had adolescent idiopathic scoliosis. The instrumentation was used in an attempt to achieve three-dimensional correction of the scoliosis, maintain lumbar lordosis, create thoracic kyphosis, and avoid the need for a postoperative cast or brace. The patients were followed for twenty-four to sixty-four months (average, thirty-five months). Cotrel-Dubousset instrumentation provided an average correction of the coronal curve of 48 per cent at the time of the most recent follow-up. The normal sagittal curves at the thoracolumbar junction and in the lumbar spine were maintained, and the thoracic kyphosis was increased slightly (average, +7 degrees). Apical translation improved an average of 60 per cent, and apical rotation improved an average of 11 per cent. Forced vital capacity improved an average of 21 per cent, and the one-second forced expiratory volume improved an average of 18 per cent. There were no major neurological deficits. A symptomatic pseudarthrosis developed in one patient. Postoperatively, decompensation of the spine developed in five of the first twenty-six patients who had a Type-II or Type-III curve. This complication was avoided in the last twenty-four patients who had a Type-II or Type-III curve by means of a stricter adherence to the definition of a Type-II curve, and reversal of the bend of the rod and the hooks between the caudal neutral and stable vertebrae. The major advantages of Cotrel-Dubousset instrumentation are the stable fixation that is achieved and the preservation of segmental lumbar lordosis.

Adolescent↗