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Biomedical subjects

M A Asher

Publications and source records attributed to M A Asher.

At least 19 recordsLinked to original sources
PubMed2001

A comparison between bipedal and quadrupedal rats: do bipedal rats actually assume an upright posture?

STUDY DESIGN: A basic science animal investigation. OBJECTIVES: To determine if bipedal rats differ in upright posture compared with quadrupedal rats. SUMMARY OF BACKGROUND DATA: It has been reported that surgically induced bipedalism in the rat leads to habitual upright posture. Based on this finding, bipedal rats have been used to study the changes erect posture induces in bone, ligament, muscle, and intervertebral discs. Previous studies have used direct observation as a means to describe posture. This study is the first to quantify postural differences between bipedal and quadrupedal rats. METHODS: Eleven bipedal rats were created by forelimb and tail amputation within 24 hours of birth. Eleven quadrupedal rats served as controls. Specialized cages were used with infrared sensors, and a computer program measured the total amount of time in the upright stance, the number of stands, and the amount of horizontal movement in the upright stance. Statistical comparisons were made between bipedal and quadrupedal rats hourly and over a 24-hour period of time. RESULTS: Quadrupedal rats assumed an upright posture for a significantly greater amount of time than bipedal rats when monitored over 24 hours (P = 0.016). Quadrupedal and bipedal rats did not differ in the number of stands (P = 0.63) or in the amount of horizontal movement in the upright stance (P = 0.34) over 24 hours. Similar results were obtained when comparing hourly intervals. CONCLUSION: This study quantifiably indicates that bipedal rats do not assume a more erect posture and spend no more time in an upright position compared with quadrupedal rats. The upright posture may not be the cause of some previously reported anatomic changes observed in the bipedal rat.

Amputation, Surgical↗
PubMed2001

Morphometry of the supra sciatic notch intrailiac implant anchor passage.

STUDY DESIGN: Anatomic study of human ilia. OBJECTIVE: To determine the anatomic dimensions influencing intrailiac anchor placement and design. SUMMARY OF BACKGROUND DATA: The development of the Galveston intrailiac implant anchor markedly improved results of spinal instrumentation to the pelvis. Better quantification of the passage dimensions is needed for the design of anatomically specific implants. METHODS: The length and outer diameter of two intrailiac anchor passages were determined from randomly selected, disease-free pairs of ilia from 129 white skeletons belonging to the Hamann-Todd Osteological Collection (Cleveland, OH, Museum of Natural History). RESULTS: Path B, an anchor passage running from the posterior superior iliac spine to the anterior inferior iliac spine, was significantly longer than path A, proceeding from the posterior superior iliac spine to the superior rim of the acetabulum, in adult and teenage males and females. For example, in adult females path B measured 141.2 +/- 7.5 mm versus 124.9 +/- 7.1 mm, P = or < 0.0001. The absolute minimum path A length available for an intrailiac post or screw anchor, following the required posterior superior iliac spine removal, was 80 mm in adults and male teenagers and 70 mm in female teenagers. For path B the hip joint was not at risk, and a safe anchor passage of at least 90 mm in teenagers and 110 mm in adults was available. The minimum thickness of the paths occurred directly above the sciatic notch. It was significantly larger in path A than path B, 20.2 +/- 2.4 mm versus 14.4 +/- 3.2 mm, P < 0.0001. CONCLUSION: Of the two supra sciatic intrailiac paths studied, the path passing from the posterior superior iliac spine toward the anterior inferior iliac spine provided a longer and potentially safer anchor site. These studies suggest techniques for accessing longer anchor paths and the need for larger diameter anchors in order to achieve optimum intra iliac anchor stiffness and strength.

Adolescent↗
PubMed2000

Further development and validation of the Scoliosis Research Society (SRS) outcomes instrument.

STUDY DESIGN: Outcome study to determine response distribution, internal consistency, and validity of a Modified SRS Outcomes Instrument (MSRSI). OBJECTIVES: Refinement and validation of the SRS Outcomes Instrument for idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Experience with the SRS Outcomes Instrument suggested several refinements and the need for validation. METHODS: Following experience-based modification, the Modified SRS Outcomes Instrument and Short Form 36 (SF-36) questionnaires were administered to 35 previously surveyed postoperative idiopathic scoliosis patients. RESULTS: Thirty (86%) patients with an average age of 25 years returned the questionnaires at an average of 10 years postoperative. Distribution of scores was acceptable. Internal consistency utilizing Cronbach's alpha was 0.80, 0.81, 0.77, 0.89, and 0.88 for pain, self-image/appearance, function/activity, mental health, and satisfaction with surgery, respectively. Validity, determined by Pearson correlation coefficients with comparable SF-36 domains, was 0.70 or greater for 13 of the 14 relevant domains between SF-36 and MSRSI (P < 0.001). CONCLUSION: The SRS Outcomes Instrument is simple and internally consistent. Based on experience, a number of modifications have been made that improve the instruments scope and internal consistency. Finally, the instrument is valid in comparison to SF-36.

Adult↗
PubMed2000

Analysis of posterior spinal wiring in a validated rabbit model.

Mamillary and spinous process base wiring did not improve L5-L6 posterolateral fusion rate, stiffness, or strength in a previously established rabbit model. Specimen radiography significantly underestimated fusion rate when compared with manual palpation (37% versus 68%). Fused specimens were significantly stiffer (67.2 N/mm versus 41.1 N/mm) and stronger (177 N versus 121 N) in tension than were nonfused specimens. Deep wound infection, detected only at the time of sacrifice, apparently was more common with internal fixation (43% versus 21%). Noninfected specimens were significantly stiffer (63.3 N/mm versus 43.0 N/mm) and stronger (176 N versus 107 N) than were infected specimens.

Animals↗
PubMed2000

Thoracolumbar kyphoscoliosis in Larsen's syndrome. A case report.

Severe thoracolumbar kyphosis in Larsen's syndrome is rare. A successful 10-year treatment course, including T2-L4 subfascial rod placement when the patient was 6 years 3 months of age, nine periodic lengthenings, and definitive surgery at age 14 years 4 months is presented. From preoperative to 2-year postoperative definitive surgery, the patient's T1 to S1 spine length increased from 19 to 36 cm. The patient's 83 degrees thoracolumbar kyphosis was transformed to 45 degrees kyphosis and 28 degrees lumbar lordosis, and scolioses of 95 degrees and 65 degrees were reduced to 64 degrees and 50 degrees.

Bone and Bones↗
PubMed2000

Scoliosis correction maintenance in skeletally immature patients with idiopathic scoliosis. Is anterior fusion really necessary?

STUDY DESIGN: A retrospective evaluation of the occurrence of the crankshaft phenomenon in skeletally immature patients with idiopathic scoliosis. OBJECTIVE: To determine what factors, if any, contribute to a decreased occurrence of crankshaft phenomenon in patients treated with posterior surgery only. SUMMARY OF BACKGROUND DATA: Reports have described the progression of scoliotic deformity, termed the crankshaft phenomenon, in a region of solid posterior arthrodesis in skeletally immature patients. This has led some authors to advocate the use of concomitant anterior discectomy and fusion to prevent crankshaft. METHODS: From 1989 through 1994, 18 Risser 0 patients with thoracic or thoracolumbar idiopathic scoliosis underwent Isola (De Puy-Acromed, Raynham, MA) posterior instrumentation and fusion. They were assessed for evidence of the crankshaft phenomenon, identified by coronal plane deformity progression of 10 degrees or more, or a rib vertebra angle difference of 10 degrees or more. The average age of the patients was 12.5 years (range, 10.5-15.5 years), and the average follow-up period was 39 months (range, 24-68 months). RESULTS: Eleven patients (10 girls and 1 boy) had closed triradiate cartilage at the time of surgery. Their average Cobb angle was 62 degrees before surgery, 21 degrees after surgery, and 22 degrees at follow-up assessment. No patients in this group met the criteria for crankshaft. Seven patients (6 girls and 1 boy) had open triradiate cartilage at the time of surgery. Their average Cobb angle was 62 degrees before surgery, 18 degrees after surgery, and 20 degrees at follow-up evaluation. No patient had a 10 degrees or more increase in rib vertebra angle difference. One patient had more than a 10 degrees increase in her Cobb angle (11 degrees) from postoperative to latest follow-up assessment. Her instrumentation construct, performed in 1989, used sublaminar wires as the caudal anchors. Hooks and pedicle screws are now used. Two of the seven patients with open triradiate cartilage underwent surgery during or before their peak height velocity and displayed no evidence of crankshaft. No deaths, neurologic complications, or infections occurred in either group. CONCLUSIONS: These findings suggest that scoliotic deformity progression can be prevented in skeletally immature patients with idiopathic scoliosis as young as 10 years of age with the use of stiff segmental posterior instrumentation, without the necessity of concomitant anterior arthrodesis.

Adolescent↗
PubMed2000

The safety and efficacy of Isola-Galveston instrumentation and arthrodesis in the treatment of neuromuscular spinal deformities.

BACKGROUND: Implant systems that realign and stabilize a deformed spine continue to evolve. The purpose of the study of this case series was to determine the safety and effectiveness of a system designed to integrate hook, wire, screw, and post anchors for the treatment of a wide spectrum of neuromuscular disorders associated with pelvic deformity or the potential for deformity. METHODS: Forty-seven consecutive patients who had a spinal deformity that was due to cerebral palsy or an upper motor-neuron cerebral palsy-like disease (thirty-one patients), myelomeningocele (nine), Duchenne muscular dystrophy (four), or other disorders (three) were managed with Isola-Galveston instrumentation and arthrodesis. The average age at the time of the operation was fourteen years and three months (range, five years and four months to twenty-three years and nine months). Eight patients (17 percent) had an additional anterior discectomy and arthrodesis without instrumentation, and three (6 percent) had an additional decancellation egg-shell osteotomy. The forty-seven patients were followed for an average of forty-seven months (range, twenty-four to 100 months). The complications were tabulated to assess the safety of the procedure, and the correction of each deformity was calculated to determine the efficacy. RESULTS: There were no deaths, acute wound infections, or serious neurological problems. Reoperation was necessary in five patients (11 percent). One reoperation was performed because of a delayed deep wound infection; one, because of delayed sterile drainage; and one, for a pseudarthrosis repair. The remaining two reoperations were done for removal of an implant because the cephalad portion had become prominent. In addition to the pseudarthrosis that required a reoperation, there were three possible pseudarthroses that did not require a reoperation (overall prevalence of pseudarthrosis, 9 percent). Postoperative bracing was used for eleven patients (23 percent); it did not influence the rate of pseudarthrosis or possible pseudarthrosis. The average preoperative scoliosis of 70 degrees was corrected to 24 degrees (a 66 percent correction) at the time of the latest follow-up, and the average preoperative pelvic obliquity of 27 degrees was corrected to 5 degrees (an 81 percent correction). A survey of the patients, parents, and caregivers indicated that 96 percent of them were satisfied or very satisfied with the result of the operation. CONCLUSIONS: Isola-Galveston instrumentation seems as safe and effective as other types of instrumentation that have been studied in comparable series in the literature. Isola-Galveston instrumentation is probably more effective for the correction of pelvic obliquity and the maintenance of correction. Only a posterior procedure is used, and the instrumentation appears to decrease the need for an additional anterior approach. Spinal hook, wire, screw, and post anchors have been successfully integrated into one posterior spinal implant system.

Adolescent↗
PubMed1999

Patients' perceptions of overall function, pain, and appearance after primary posterior instrumentation and fusion for idiopathic scoliosis.

STUDY DESIGN: This outcome study used patients' responses to the Scoliosis Research Society Outcomes Instrument to discriminate among patients who had undergone surgery for correction of juvenile or adolescent idiopathic scoliosis. OBJECTIVES: To evaluate a surgically treated population by using the SRS Outcomes Instrument. SUMMARY OF BACKGROUND DATA: The Scoliosis Research Society outcomes instrument was developed to help evaluate patient-perceived outcomes after treatment for idiopathic scoliosis. It includes 24 questions designed to investigate seven domains. METHODS: Eligible patients underwent posterior surgery for the first time before their 21st birthdays. One surgeon performed the surgery at one medical center. Of 168 eligible patients, 121 (72%) completed the Scoliosis Research Society outcomes questionnaire. RESULTS: Females reported better outcomes in the function after surgery (P = 0.005) and self-image after surgery (P = 0.01) domains. Preoperative curve pattern comparison demonstrated a significant difference in self-image after surgery among four groups classified according to curve pattern. The thoracolumbar and lumbar group recorded image scores of 5, the highest possible score, 85% of the time. The King-Moe (KM) V group scored 5, 75% of the time; the KM I and II group 48%; and the KM III and IV group 46% (P = 0.0015). After eliminating confounding variables, it was found that white patients reported experiencing less pain in follow-up than did black patients (P = 0.0098). Results were also suggestive that less pain was associated with increased number of fused vertebrae (P = 0.027). CONCLUSIONS: The strongest predictors of self-perceived favorable outcome among patients were female sex and white race. It is also suggested that longer fusions to L1 through L3 lead to less perceived pain than with shorter fusions.

Adolescent↗
PubMed1999

The selection of fusion levels using torsional correction techniques in the surgical treatment of idiopathic scoliosis.

STUDY DESIGN: This is a retrospective, consecutive case series, with the index patient included. OBJECTIVES: To evaluate the evolution and effectiveness of instrumentation techniques designed to untwist the scoliosis deformity. SUMMARY OF BACKGROUND DATA: Three-dimensional studies of the idiopathic scoliosis deformity are consistent with the theory that the deformity or deformities evolve as an imperfect torsion or torsions. METHODS: From 1989 through 1995, 102 consecutive patients (84 females, 18 males) underwent surgery with increasing emphasis on torsional correction. One hundred patients (98%), with an average age of 14.3 years (range, 10.5-20.8 years), were observed for an average of 40 months (range, 24-81 months). The upper instrumented vertebra evolved to be the centered vertebra. The lower instrumented vertebra was chosen based on its ability to become horizontal on contralateral bend radiographs and was termed the caudal foundation vertebra. Because these techniques evolved over the first 3 years of the study period, a split analysis was performed to evaluate improvements in correction and correction maintenance over the course of the study. RESULTS: The average Cobb angle was 59 degrees before surgery, 18 degrees after surgery (69% correction), and 22 degrees (63% correction) at latest follow-up. A comparison of the first half of the series with the second half showed no significant demographic differences. Curve correction was significantly improved for King-Moe IIB (thoracolumbar-lumbar curve only), King-Moe III, and King-Moe V curve types in the second half of the series. In the last 4 years, curve correction at latest follow-up for King-Moe IIB curves was 61% for the thoracic curve and 65% for the thoracolumbar-lumbar curve. King-Moe III curves had a 68% correction, and King-Moe V curves had a 50% high thoracic and a 72% thoracic curve correction. Thoraco-lumbar, lumbar, and King-Moe I curves averaged 81% correction of the thoracolumbar-lumbar curve. The angle of thoracic curve inclination improvement at 1 year was maintained at latest follow-up. CONCLUSIONS: This method of selecting instrumentation levels while using torsional correction techniques is safe and reliable. The results were improved with the evolution of these techniques and appear to provide improved correction and correction maintenance compared with that of historical controls.

Adolescent↗
PubMed1999

A concept of idiopathic scoliosis deformities as imperfect torsion(s).

Scoliosis is a complex three-dimensional deformity. With continued improvement in spinal implant design, the options for corrective load application have increased. Visualization of the scoliosis deformity as a torsion or torsions, similar to an elongated helical line, and integration of this visualization with current deformity classification have proven useful in developing instrumentation sequences addressing scoliosis as a three-dimensional deformity. These instrumentation sequences, which have been evolving since 1989, have been applied in more than 150 patients who show improved deformity correction without serious complications.

Biomechanical Phenomena↗
PubMed1999

Traumatic L5-S1 spondylolisthesis.

We report a case of traumatic spondylolisthesis in a 31-year-old man struck by a steel I-beam. Although most reported traumatic spondylolisthesis cases are from low-energy trauma, this was a high-energy trauma case. The initial examination revealed no signs of cauda equina syndrome, and the patient's spinal injury was primarily capsuloligamentous. We present this rare case, with a review of pertinent literature and treatment mechanisms for traumatic spondylolisthesis.

Accidents, Occupational↗
PubMed1997

Freeze-dried allograft for posterior spinal fusion in patients with neuromuscular spinal deformities.

STUDY DESIGN: The effectiveness and safety of freeze-dried allograft for posterior spinal fusion in patients with neuromuscular disorders were evaluated retrospectively. SUMMARY OF BACKGROUND DATA: Because the harvest of an adequate quantity of autogenous bone graft from patients with neuromuscular deformity who have instrumentation and fusion to the pelvis is difficult at best, an alternative graft source usually is needed. Allograft bone, most commonly processed fresh-frozen or freeze-dried, has been used frequently for posterior spinal fusion in patients with neuromuscular deformity. However, a relatively high risk of infection and pseudarthrosis has been reported for this procedure. METHODS: Forty patients with neuromuscular deformity with an average age at the time of surgery of 14 years and 2 months (range, 5 years, 4 months to 23 years, 8 months) met the inclusion criteria. All of these patients underwent more than 2 years of follow-up evaluation. They were evaluated for rates of infection, pseudarthrosis, and transmissible disease. RESULTS: Thirty-eight patients had solid fusion at the most recent follow-up visit. Definite pseudarthrosis was detected in one patient (2.5% of the study group), which was treated successfully. Another patient's (2.5%) spinal curve progression of more that 10 degrees and rod breakage led the authors to diagnoses a probable pseudarthrosis. She had a stable spine that did not require revision at 68 months after surgery. For the 32 patients who underwent posterior surgery only, the pseudarthrosis rate was 3.1%. There were no acute deep wound infections. Superficial infection occurred in two patients (5%) and delayed deep sterile drainage in one patient (2.5%). All cases of infection resolved with appropriate management. Delayed deep wound infection developed in one patient (2.5%) as a result of staphylococcus coagulase negative at 34 months after surgery. Successful treatment has consisted of implant removal, debridement, and appropriate antibiotics. Transmissible disease attributable to allograft has not been detected to date. CONCLUSION: Freeze-dried allograft fusion is a reliable and effective method for posterior spinal fusion in the patients with neuromuscular deformity.

Adolescent↗
PubMed1996

Overpowering the crankshaft mechanism. The effect of posterior spinal fusion with and without stiff transpedicular fixation on anterior spinal column growth in immature canines.

STUDY DESIGN: This experimental study was designed to test the hypothesis that posterior spinal fusion and internal fixation, using a stiff transpedicular construct, would withstand additional anterior column growth without the need for an anterior procedure and would prevent the development of deformity secondary to asymmetric growth of the anterior column in the immature canine model. OBJECTIVES: This model revealed that a mechanical epiphysiodesis of the anterior spinal column can be created through a posterior approach in an immature growing animal using a stiff transpedicular construct. These results were correlated to the crankshaft mechanism clinically to provide a possible rationale for transpedicular posterior spinal instrumentation and fusion, without a concomitant anterior procedure, in immature patients. SUMMARY OF BACKGROUND DATA: All operative immature canines underwent posterior fusion of L1-L5 vertebral bodies with autogenous iliac crest bone graft. Instrumented canines underwent the additional placement of transpedicular screws at L1, L3, and L5 as well as 3/16-inch rods and a transverse connector. Previous studies have revealed that continued anterior spinal column growth after posterior arthrodesis causes a resultant deformity in quadrupeds. No previous study has assessed whether a transpedicular construct can overpower the anterior spinal growth plate in an immature growing model. METHODS: Twenty-five skeletally immature canines were randomized into four groups: control, fusion only, screw and fusion, and instrumentation and fusion. Disc space growth, vertebral body growth, and sagittal plane angulation were the variables analyzed. Management response variables were visualized graphically and radiographically. RESULTS: Posterior tethering and anterior column growth occurred in the noninstrumented fusion groups, producing substantial lordosis. Anterior column growth was arrested in the instrumented canines as demonstrated by decreased vertebral body length, disc space narrowing, and, most importantly, prevention of lordosis. CONCLUSIONS: The present study confirmed that in immature canines anterior column growth continues after posterior fusion without instrumentation. The magnitude of this growth, combined with a posterior tether, is sufficient to cause significant lordosis. The results are the first to document that a stiff posterior spinal instrumentation system is sufficient to overpower the residual anterior growth centers, even in the presence of a posterior tether (fusion mass). This technique creates a mechanical epiphysiodesis evidenced by arresting vertebral body length, narrowing disc space, and preventing lordosis, thus thwarting the deformity-producing mechanism without an additional anterior procedure.

Age Factors↗
PubMed1996

The safety and efficacy of the Isola Spinal Implant System for the surgical treatment of degenerative disc disease. A prospective study.

STUDY DESIGN: This is a prospective study designed in consultation with and approved by the Food and Drug Administration with the purpose of determining the safety and efficacy of the Isola Spinal Implant System for the surgical treatment of patients with degenerative disc disease. OBJECTIVES: To report the results of the degenerative disc disease group from the Isola Investigational Device Exemption study, which was done to determine whether the Isola Spinal Implant System is a safe and effective treatment. SUMMARY OF BACKGROUND DATA: The safety and efficacy of transpedicular instrumentation as an adjunct in achieving lumbar spine fusion are still debated. METHODS: Hospital Investigational Review Board approval of the study protocol was obtained at the 10 participating centers. One hundred twenty patients (49 men and 71 women; average age, 54 years [range, 25-83 years]) were enrolled. Clinical and radiographic follow-up evaluation was done using protocols established prospectively. RESULTS: Of the 120 patients, 12 (10%) had device-related problems. There were two operative and four device related complications after surgery. Six other patients had their implants removed either for local pain (two) or for looseness or breakage (four). Of 118 patients eligible for follow-up evaluation at 24 months, 107 (91%) were available for study. Fusion was achieved in 97 (91%) patients. Average combined function and pain scores improved by 2.6 points (P < 0.0001). Clinical success, as measured by combining function and pain scores, was achieved in 65% of the patients by the most stringent criteria and 73% by less stringent criteria. Clinical success was significantly higher in patients who had not had previous surgery than in those who had, 77% versus 57% (P = 0.04). CONCLUSIONS: The present study suggests that the Isola Spinal Implant System can be safely used, is an effective adjunct in the achievement of fusion, and yields an acceptable number of successful clinical outcomes, especially when considering the preponderance of previously operated patients included in this group.

Bone Nails↗
PubMed1995

The transverse plane evolution of the most common adolescent idiopathic scoliosis deformities. A cross-sectional study of 181 patients.

STUDY DESIGN: The transverse plane evolution of the most common idiopathic deformities was studied using a cross-sectional database of 181 patients whose deformities were visualized by precise three-dimensional techniques. OBJECTIVE: The objective was to test the hypothesis that for all common idiopathic scoliosis deformities evolution occurs as a torsion, the apex vertebra translating away from the upper end vertebra and at the same time angulating in a clockwise arc for right apex deformities and a counterclockwise arc for left apex deformities. SUMMARY OF BACKGROUND DATA: Perdriolle and Vidal proposed this hypothesis in 1987, which explained observations we had made in 1983 and which was partially supported in thoracic curves in our 1992 study. METHODS: Deformities were characterized as single thoracic major, thoracic major and thoracolumbar or lumbar minor, double thoracic and thoracolumbar or lumbar major, and single thoracolumbar or lumbar major curves. The dependent variable studied was the coronal plane regional angular (Cobb) deformity. The independent variables studied were the lateral and anteroposterior translation of the apex vertebra in relation to the upper end vertebra, and the transverse plane translation and angulation of the apex vertebra in relation to the upper end vertebra. For the model or hypothesis to be true, the apex vertebra to upper end vertebra transverse plane translational distance and angular relationship should increase as the Cobb angle increases. RESULTS: In relation to the upper end vertebra, the apex vertebra always translated laterally, almost always was accompanied by transverse plane translation increase, and usually was accompanied by transverse plane angulation increase. Anteroposterior translation was minimal, but for thoracolumbar and lumbar curves it tended to be posterior. CONCLUSION: The theory that these deformities evolve as torsions, with the apex vertebra translating away from the upper end vertebra and at the same time following a clockwise angular pathway to the upper end vertebra of right apex curves and a counterclockwise angular pathway for left apex curves is supported. Compensatory thoracolumbar and lumbar curves evolve in the same manner as major curves.

Adolescent↗
PubMed1995

Iliac crest bone graft harvest donor site morbidity. A statistical evaluation.

STUDY DESIGN: This study analyzed the cause, rate, and risk factors of iliac crest bone graft donor site morbidity. OBJECTIVES: All complications or problems, no matter how small, were sought to develop strategies of prevention. SUMMARY OF BACKGROUND DATA: A wide range of major, 0.76% (Keller et al) to 25% (Summers et al) and minor complications, 9.4% (Keller et al) to 24% (Summers et al) has been reported. METHODS: A consecutive series of 261 patients, whose bone graft harvest was done by one surgeon, was studied by chart review and a mail survey that was not conducted by the operating surgeon. The survey presented specific open-ended questions designed to uncover any complication/problem, no matter how small. Complications then were categorized as major or minor and subcategorized as acute or chronic. Statistical analysis was done using chi-squared and multiple logistical regression. RESULTS: None of the 261 patients had a severe perioperative complication--e.g., superior gluteal artery injury, sciatic nerve injury, or deep wound infection. None of the 225 patients with long term follow-up (average, 66 months; range, 32-105 months) had a severe late complication--e.g., donor site herniation, meralgia paresthetica, pelvic instability, or fracture. Of the 180 patients meeting the qualifications for statistical analysis, major complications occurred in 18 (10%), only three of which affected function (pain). Minor complications occurred in 70 (39%). CONCLUSIONS: The results indicated that severe complications from iliac crest bone graft harvest can be avoided and major complications affecting functioning are uncommon, but minor complications are common. The findings suggest that procedural refinements of limiting subcutaneous dissection and providing layered tension-free incision closure may improve results.

Adolescent↗
PubMed1994

The strength and stiffness of thoracic implant anchors in osteoporotic spines.

OBJECTIVE: To gain a better understanding of factors affecting dorsal implant pull-out strength and stiffness so thoracic spinal implant fixation can be improved. METHODS: Posterior pull-out testing of six thoracic implant anchor types was performed on 54 osteoporotic human vertebra, T2-10, with an average bone mineral density of 0.67 g/cm2. RESULTS: The mean loads at neural arch failure were similar (296 to 382 N). Pedicle strength was greatest at T2 and least at T3. Hook claws were stiffer than sublaminar wires (121 N/mm and 180 N/mm versus 42 N/mm and 52 N/mm, respectively). Facet hook and pedicle hook claws were comparable, as were subpars wires. Bone mineral density of the vertebral bodies correlated with the stiffness of the sublaminar wire anchors only. CONCLUSION: To optimize the strength and stiffness of implant constructs designed to resist forward flexion, this study supports using hook-claws rather than sublaminar wires and extension of fixation to T2 when clinically realistic.

Aged↗