Biomedical subjects

H S An

Publications and source records attributed to H S An.

At least 73 records · Page 4Linked to original sources

PubMed1995

Comparison between allograft plus demineralized bone matrix versus autograft in anterior cervical fusion. A prospective multicenter study.

STUDY DESIGN: This study analyzed the fusion results of an allograft-demineralized bone matrix composite versus autograft in a prospective series of patients undergoing surgery for cervical disc disease. OBJECTIVES: To determine the fusion rates of allograft-demineralized bone matrix composite in anterior cervical fusion as compared with the gold standard autograft. SUMMARY OF BACKGROUND DATA: For the anterior cervical fusion, the use of freeze-dried allograft is well documented in the literature, citing its effectiveness and inferior fusion rates. The use of demineralized bone matrix in conjunction with freeze-dried allograft in anterior cervical fusion has not been reported. METHODS: This study was done in a prospective fashion in two medical centers. One group received autograft from the anterior iliac crest, whereas others received freeze-dried allograft augmented with demineralized bone matrix (Grafton, Osteotech, Inc., Shrewsbury, New Jersey). For the autograft group, the standard Smith-Robinson grafting technique was used. For the allograft composite group, demineralized bone matrix was pasted onto the freeze-dried allograft and into the disc space before graft insertion. The autograft group consisted of 38 patients with age ranging 26-71 years (mean, 46.1 years) and follow-up periods of 12-33 months (mean, 18.4 months). There were 19 one-level, 17 two-level, and two three-level fusions. Similarly, the allograft group consisted of 39 patients with age ranging 28-80 years (mean, 48.0 years) with follow-up period of 12-31 months (mean, 17.5 months). There were 19 one-level, 16 two-level, and four three-level fusions. Clinical and radiographic follow-up evaluations were completed at 3-month intervals. Radiographs taken 12 months after surgery were analyzed blindly. RESULTS: Pseudarthrosis developed in 46.2% of patients (33.3% of levels) in the allograft-demineralized bone matrix group compared with 26.3% (22% of levels) in the autograft group (P = 0.11 for patients, P = 0.23 for levels). For patients undergoing two-level fusions, 37.5% of allograft-demineralized bone matrix failed compared with 23.5% of autografts. For single-level fusions, 47.4% of allograft patients developed a pseudarthrosis compared with 26.3% in the autograft group. Graft collapse of > or = 3 mm was noted in 11% of the autograft group versus 19% in the allograft-demineralized bone matrix group (P = 0.32). Graft collapse of > or = 2 mm occurred in 24.4% of autograft patients compared with 39.7% of the allograft-demineralized bone matrix group (P = 0.09). Smokers had an increased rate of pseudarthrosis (47.1%) compared with nonsmokers (27.9%, P = 0.13). CONCLUSIONS: The study revealed that the allograft-demineralized bone matrix construct gives a higher rate of graft collapse and pseudarthrosis when compared with autograft in a prospective series, although the differences were not statistically significant. The pseudarthrosis rate in the series may be high because of the large percentage of smokers and radiographic evaluation techniques. For the purpose of solid radiographic fusion, the use of autograft is recommended in anterior cervical surgery until other acceptable osteoinductive materials are developed.

Adult↗

PubMed1995

Biomechanical evaluation of anterior thoracolumbar spinal instrumentation.

STUDY DESIGN: A biomechanical study was designed to assess relative construct stabilities of modern anterior thoracolumbar instrumentations in a calf spine model with an anterior and middle column defect. OBJECTIVES: The purpose is to compare the biomechanical stability of various anterior fixation devices in an unstable calf spine model. SUMMARY OF BACKGROUND DATA: Modern types of anterior thoracolumbar instrumentations evolved to either rods or plates. Biomechanical properties and comparative studies of these instrumentations are lacking. METHODS: Twenty fresh calf spines (L2-L5) were used for the biomechanical tests. L2 and L5 vertebrae were used to attach the loading and base frames, respectively. Specimens underwent nondestructive biomechanical tests performed using a three-dimensional motion measuring system. In each specimen, three different cases were tested: intact spine, anterior fixation with an interbody graft after total discectomy and endplate excision of L3-L4 disc, anterior fixation only without the graft. Four anterior fixators, University Anterior Plating System, the Kaneda device, the Z-plate, and Texas Scottish Rite Hospital system were used. Each device was tested on five specimens. A polymethylmethacrylate block was inserted into the disc space to simulate the interbody grafting, and a fixation device was implanted with axial compression. Rotational angles of the L3-L4 segment stabilized by a fixation device and graft were normalized by the corresponding angles of the intact specimen to study the overall stabilizing effects. RESULTS: With the interbody graft and fixation devices, all showed significant stabilizing effects in flexion, extension, and lateral bending. All devices restored axial rotation stability to intact specimen, but only the Kaneda device restored the torsional stability beyond the intact specimen. No statistical differences in stabilizing effects in axial rotation were found between any of the tested devices. When the graft was removed, the Kaneda device significantly decreased the motions in all directions compared with the intact motion, whereas the University plate decreased the motions in flexion, extension, and lateral bending. The Texas Scottish Rite Hospital system was found to reduce the flexion and lateral bending motions significantly, and Z-plate decreased lateral bending motions only. Stabilizing effects of the interbody graft were significant in lateral bendings for all devices. Additionally, the significant stabilizing role of the graft was noted in flexion and extension in Z-plate only. The graft did not significantly reduce the axial rotation motion in any instrumentations. CONCLUSIONS: Modern anterior instrumentations for the thoracolumbar spine, such as the Kaneda device, Texas Scottish Rite Hospital system, Z-plate, and University plate, restored the stability in all motions when an interbody graft was inserted. The stability of fixation devices revealed that the Kaneda device is the best, particularly in restoring the torsional stability. The information on the relative stability provided by different instrumentations should help the spine surgeon in choosing the appropriate instrumentation for the particular circumstance.

Analysis of Variance↗

PubMed1995

Can we distinguish between benign versus malignant compression fractures of the spine by magnetic resonance imaging?

STUDY DESIGN: The authors investigate the usefulness of magnetic resonance imaging in differentiating benign versus malignant compression fractures by reviewing patients and a fracture model in a canine model. OBJECTIVES: To determine the sensitivity and specificity of magnetic resonance imaging in differentiating benign versus malignant compression fractures of the spine and to obtain distinguishing features in magnetic resonance imaging. SUMMARY OF BACKGROUND DATA: The differentiation between benign and abnormal compression fractures of the thoracolumbar spine has important implications regarding patient treatment and prognosis. Plain radiographs, bone scans, and computed tomography are not accurate imaging modalities for this purpose. METHODS: Magnetic resonance imaging scans of 22 patients with confirmed lesions of the thoracolumbar spine were studied. There were 11 malignant and 11 benign lesions. Two experienced neuroradiologists blindly reviewed the magnetic resonance imaging scans and determined benign or malignant lesions. A canine study was performed to simulate a compression fracture model with a vertebral osteotomy in two dogs, and serial contrast-enhanced magnetic resonance imaging scans were performed 15, 30, 60 and 90 days after surgery. RESULTS: The correct interpretation between two neuroradiologists was 77% and 95%. The combined sensitivity rate was 88.5%, and the specificity rate was 89.5%. Magnetic resonance imaging reliably distinguished benign versus malignant lesions based on the anatomic distribution and intensity of signal changes of bone and adjacent tissues, contrast enhancement characteristics, and changes over time. Only one malignant lesion was misinterpreted by both neuroradiologists as benign, whereas there was one additional missed malignant lesion and three misinterpreted benign lesions by one radiologist. In the canine study, signal changes and enhancement were found 60 days after surgery, but no signal changes or enhancement were noted on the scan 90 days after surgery. CONCLUSIONS: Magnetic resonance imaging scans can detect malignant vertebral lesions early, but acute healing compression fractures may mimic the findings of metastatic lesions. The use of contrast-enhanced magnetic resonance imaging scans and serial magnetic resonance imagings are helpful for additional differentiation between benign and malignant compression fractures. In addition to magnetic resonance imaging scans, other diagnostic tests and clinical findings should be correlated before biopsy or surgery of the suspected lesion.

Adult↗

PubMed1995

Placement of pedicle screws in the thoracic spine. Part II: An anatomical and radiographic assessment.

We used computerized tomographic scans and subsequent dissections to evaluate the position of ninety pedicle screws that had been inserted bilaterally into the fourth through twelfth thoracic vertebrae of five fresh-frozen cadavera. The screws had been inserted by five experienced spine surgeons without the use of radiographs or imaging studies. Of the ninety screws, thirty-seven were found to have penetrated the cortex of the pedicle. Twenty-one screws had penetrated the medial cortex and entered the spinal canal, and sixteen had penetrated the lateral cortex. The aorta and the esophagus were at greatest risk for injury after advancement of the screws beyond the anterior vertebral cortex. Computerized tomographic scans of the thoracic spine in nineteen living controls who did not have a spinal abnormality confirmed the proximity of the posterior mediastinal structures to the misplaced screws.

Aorta↗

PubMed1995

Strength of anterior vertebral screw fixation in relationship to bone mineral density.

A biomechanical study was performed to investigate the relationship among the pullout strength of anterior vertebral screw fixation, bone mineral density (BMD) of the vertebral body, screw insertion torque, and width of the vertebral body. BMD was measured using a dual energy x-ray absorptiometry unit. Screw insertion torque and width of the lumbar vertebrae were also measured before the pullout test. Pullout strength was significantly correlated with BMD (r = 0.85) and screw insertion torque (r = 0.47), but not with width of the vertebral body. Multiple regression analyses demonstrated better correlation between pullout strength and the other parameters (r = 0.886). A stepwise regression analysis showed that BMD is the most significant predictor of the pullout strength followed by width of the vertebral body, whereas screw insertion torque is not a significant predictor. Furthermore, the mean pullout strength of the grade I osteoporosis group was significantly greater than that of grade II or III osteoporosis group.

Absorptiometry, Photon↗

PubMed1995

Prospective comparison of autograft vs. allograft for adult posterolateral lumbar spine fusion: differences among freeze-dried, frozen, and mixed grafts.

The use of allografts continues today for the purpose of spinal fusion. The literature is conflicting on the effectiveness of allografts in spinal fusion as compared with autografts. Numerous variables affect fusion, including age, sex, smoking status, type of surgery, and anterior versus posterior surgery. Therefore, we have undertaken a prospective study in which comparison was made between allograft and autograft in the same individual. The purpose of this prospective study was to compare autografts, frozen allografts, freeze-dried allografts, and a mixture of allograft and autograft in the same patient undergoing an instrumented posterolateral lumbar spine fusion. Twenty patients (nine men and 11 women with ages ranging from 29-72 years and a mean age of 43.5 years) underwent posterolateral fusions of the lumbar spine with pedicle screw instrumentation. An autogenous posterior iliac crest bone graft was placed on one side in each patient and an allograft on the other side. Assessing bone fusion quality from grades 1 to 4, the autograft side had a grade 1 solid fusion in 16 of 20 cases (80%). On the other hand, freeze-dried grafting resulted in grade 4 resorption in all seven cases. Frozen allografts resorbed in three of five cases, and partial fusions were achieved in the remaining cases. When a mixture of autograft and freeze-dried allograft was used, grade 1 solid fusion was achieved in four of eight cases and partial fusions were achieved in the others. Bone densitometry results also showed that autograft sites gave significantly greater bone density, followed by mixture, frozen allografts, and freeze-dried allografts in this order.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Contrast enhancement in spinal nerve roots: an experimental study.

PURPOSE: To examine histopathologically the endothelium of contrast-enhancing spinal nerve roots. METHODS: In five adult baboons, chronic compression of the left S-1 spinal nerve root sufficient to produce a change in the evoked potential was produced by means of a suture tied around the nerve. The animals were studied with MR at 8 and 16 days after nerve compression and then killed for histopathologic and electron microscopic studies. Histopathologic changes in the nerve roots demonstrating contrast enhancement were described. RESULTS: In all compressed spinal nerves, contrast enhancement was observed. Histopathologically, wallerian degeneration of the root and inflammation and disruption of the endothelium of capillaries in the spinal nerve were evident. CONCLUSIONS: Degenerative changes in the nerve root and the capillary endothelium of a lumbar spinal nerve are associated with contrast enhancement.

Animals↗

PubMed1995

Lumbar foraminal stenosis: critical heights of the intervertebral discs and foramina. A cryomicrotome study in cadavera.

One hundred lumbar intervertebral foramina from eighteen spines of fresh cadavera were studied to assess the relationship between compression of the nerve root and the height of the intervertebral disc and the morphological characteristics of the intervertebral foramen as determined on cryomicrotome sections. The critical posterior disc height and the critical foraminal height that were associated with entrapment and compression of the nerve root were determined. Significant positive correlations were demonstrated between compression of the nerve root and the posterior disc height, the foraminal height, and the foraminal cross-sectional area for the four intervertebral levels between the second lumbar and first sacral vertebrae. Nerve-root compression was evident in twenty-one of the 100 foramina, in eight of the ten foramina in which the posterior disc height was four millimeters or less, and in four of the five foramina in which the foraminal height was fifteen millimeters or less. These critical dimensions may be indicators of foraminal stenosis in the lumbar spine. However, compression of a spinal nerve root does not always cause sciatica, and the clinical findings must always be taken into account when a diagnosis of stenosis is considered.

Adult↗

PubMed1994

Spinal disorders at the cervicothoracic junction.

STUDY DESIGN: This study reviewed 36 retrospective patients who underwent surgeries for rare cervico-thoracic junctional problems. OBJECTIVES: The authors review cervico-thoracic junctional disorders and study diagnostic methods, surgical approaches, surgical outcomes, and associated complications. SUMMARY OF BACKGROUND DATA: The literature is sparse on cervico-thoracic junctional problems. This paper is the largest series to date on this subject. METHODS: Thirty-six patients who underwent surgeries for spinal problems at the cervico-thoracic region (C7-T3) were reviewed. These included 18 patients with trauma, 15 patients with tumors, 2 patients with herniated discs, and one patient with postlaminectomy instability. There were 20 males and 16 females. The age ranged from 17 to 83 years with a mean of 43.5 years. Surgically, 21 patients had only posterior procedures, that included 12 wiring, 5 Luque rodding, 1 plate-screw fixation for postlaminectomy instability, 1 transpedicular biopsy, 1 foraminotomy for herniated C7-T1 disc, and 1 costotransversectomy for T2-T3 herniated disc. Neurologically, the majority of traumatic patients presented with neurologic deficits (10 complete and 4 incomplete, and 1 root injuries), and nontraumatic disorders were associated with 10 incomplete cord syndromes and 5 root dysfunctions. RESULTS: Follow-up average was 38 months based on 33 of 36 patients. There were three postoperative deaths (two sternotomies, one anterior C7 corpectomy). Neurologically, patients with complete cord injuries remained complete, whereas patients with incomplete or root deficits improved significantly. Complications included C6-C7 subluxation after C7-T2 fusion, pseudomeningocele, vocal cord paralysis, dysphagia, and Horner's syndrome. Other complications included wound infections, urinary tract infections, decubiti, deep vein thrombosis, pneumonia, and tumor recurrence. CONCLUSIONS: In treating patients with cervico-thoracic problems, one should do careful clinical and radiologic survey to avoid missed or delayed diagnoses, and the surgeon must be thoroughly familiar with anterior and posterior landmarks and associated vital structures and remember that the cervico-thoracic junction is an area of potential instability particularly after trauma or laminectomy. Complications of surgery at the cervico-thoracic junction are frequent, and meticulous surgical techniques and postoperative care are important in the prevention of these complications.

Adult↗

PubMed1994

Prediction of bone graft strength using dual-energy radiographic absorptiometry.

STUDY DESIGN: A biomechanical study of anterior iliac crest bone was done to investigate a relationship between the compressive strength of tricortical iliac crest grafts and bone mineral density (BMD) of the iliac crest measured by dual-energy x-ray absorptiometry (DEXA). OBJECTIVES: This study investigated the potential usefulness of DEXA for measuring BMD of the iliac crest and documented bone graft strength predictability by BMD measurements. SUMMARY OF BACKGROUND DATA: The corticocancellous iliac bone is frequently used as an interbody graft for anterior spine fusion. The decreased compressive strength of bone graft may lead to collapse, pseudarthrosis and recurrence of symptoms, particularly in the osteoporotic patient. The DEXA accurately determines BMD of the spine and the hip, but no previous studies are available on the pelvis. METHODS: The BMDs were measured on the intact pelvis of the elderly and the corresponding tricortical grafts, using DEXA. The strut and Smith-Robinson type grafts were placed under axial loading using Material Testing System. Load to failure and compressive strength were obtained and statistically correlated to BMDs. RESULTS: There was a high correlation between the BMDs of the intact pelvis and each graft (R = 0.8, P < 0.001). The ultimate load to failure and compressive stress were linearly correlated to the BMD of the intact pelvis (R = 0.82, P < 0.001, R = 0.78, P < 0.001, respectively) as well as to the BMD of the graft (R = 0.77, P < 0.001, R = 0.75, P < 0.001, respectively). CONCLUSIONS: These results suggest that the biomechanical strength of the iliac bone graft is very dependent on its BMD, and DEXA has a potential clinical value in predicting iliac bone graft strength for cervical spine fusion.

Absorptiometry, Photon↗

PubMed1994

Gadolinium-enhancement characteristics of magnetic resonance imaging in distinguishing herniated intervertebral disc versus scar in dogs.

STUDY DESIGN: This study is an experimental investigation on the gadolinium contrast magnetic resonance imaging (MRI) in distinguishing sequestered disc fragment versus scar in dogs. The conspicousness of the disc fragment and signal intensities of the disc fragment and laminectomy scar were evaluated using gadolinium-enhanced MRI and histology. OBJECTIVES: This study investigated the effects of timing of gadolinium injections, gadolinium doses, and aging of scar or disc on the enhancement characteristics and conspicuousness of disc fragment in MRI. SUMMARY OF BACKGROUND DATA: Contrast-enhanced MRI has been frequently used as a procedure to evaluate patients with suspected recurrent herniated discs. In contrast-enhanced MRI, the postoperative scar tissue enhances to a greater extent than disc fragments. Previous reports suggest different contrast enhancement characteristics of scar depending on doses, timing of gadolinium, or maturity of scar. There are different compounds of gadolinium agents and different doses are becoming available. There is no previous report on the evaluation of gadolinium enhancement characteristics in dogs with concurrent herniated disc and scar. METHODS: Six conditioned Beagle dogs underwent hemilaminectomies and discectomies at the L3-L4 level. An autogenous disc fragment was obtained from the intervertebral disc of the tail. This disc fragment was placed anterolateral to the thecal sac, simulating a sequestered disc herniation. Three control animals underwent hemilaminectomies and discectomies alone. Each dog underwent MRI on a 1.5 Tesla scanner (3.0 mm slice in sagittal and axial projections with TR 500, TE 30 msec and high dose 0.3 mmol/kg of gadoteridol). Images were obtained at 15 days, 30 days, 60 days, and 90 days after surgery. At each imaging session, contrast enhancement was measured at 2 minutes, 25 minutes, and 45 minutes after gadolinium injection for kinematic analysis. Two animals at a time were killed on 30 days, 60 days, and 90 days postoperatively. Magnetic resonance imaging was done with conventional low dose 0.1 mmol/kg of gadopentetate at 15 days and before death. RESULTS: Results revealed that the difference of enhancement between disc and the scar and therefore conspicuousness of disc fragment was greater on 2-23-minute images as compared with 45- minute images, and the distinction decreased with aging of the scar. The high dose contrast-enhanced MRI increased signal intensities for both disc and scar. Conspicuousness of disc fragment seemed to be better with the high-dose gadolinium compound. CONCLUSIONS: In conclusion, contrast enhancement characteristics in MRI may depend on the timing of MRI after gadolinium injection, doses of gadolinium, and aging of scar or disc.

Animals↗

PubMed1994

Comparison of smoking habits between patients with surgically confirmed herniated lumbar and cervical disc disease and controls.

There have been numerous studies that implicate cigarette smoking as a risk factor for the development of back pain or disc disease. The purpose of this article is to review patients who underwent surgery for cervical or lumbar radiculopathy and to investigate the relationship between cigarette smoking and development of surgical disc disease. A cigarette smoking study of 205 surgical patients with lumbar and cervical disc diseases was done, with the surgical patients compared to 205 age-sex-matched inpatient controls during 1987-1988. This study was conducted at the Pennsylvania Hospital in Philadelphia, Pennsylvania. There were 163 patients with lumbar disc disease and 42 patients with cervical disc disease. The ratio of men to women was 1.5:1 for lumbar disc and 2.5:1 for cervical disc disease. Smoking history (current and ex-smokers) was strikingly increased in both prolapsed lumbar intervertebral disc (56% vs. 37% of controls, p = 0.00029) and cervical disc disease (64.3% vs. 37% of controls, p = 0.0025). Calculated relative risks for smokers were 2.2 for lumbar disc and 2.9 for cervical disc diseases. This association between cigarette smoking and disc disease was more significant when comparing between current smokers versus nonsmokers (p = 0.000011 for lumbar disc disease, and p = 0.00064 for cervical disc disease). Relative risks for current smokers were 3.0 for lumbar disc and 3.9 for cervical disc diseases. This correlation was significant for both males (p = 0.000068 for lumbar disc disease, p = 0.043 for cervical disc disease) and females (p = 0.018 for lumbar disc disease, p = 0.006 for cervical disc disease).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Ideal thickness of Smith-Robinson graft for anterior cervical fusion. A cadaveric study with computed tomographic correlation.

To establish the optimal thickness for Smith-Robinson anterior cervical fusion grafts, anterior C4-5 discectomy and fusions were performed on six fresh, frozen cadavers. Plain radiographs and computed tomographic scans then were employed to correlate graft placement with changes in disc space height, foraminal height, and foraminal areas after 3-, 5-, 7-, and 9-mm interbody fusions. The ideal graft thickness appeared to be directly related to the preoperative baseline disc height. For a preoperative disc height of 3.5-6.0 mm, an interbody graft of 2 mm above baseline thickness was most appropriate. A thicker graft was required when the baseline disc height was smaller (2.0 mm) and a thinner graft when the disc height was larger (7.4 mm). No significant correlation was noted between disc space distraction at C4-5 and disc height, foraminal height, or foraminal area at adjacent levels.

Aged↗

PubMed1993

Thoracic disc herniation. Re-evaluation of the posterior approach using a modified costotransversectomy.

A consecutive series of 23 thoracic disc herniations in 21 patients treated between 1980 and 1988 were reviewed. All patients were decompressed through a posterolateral approach (costotransversectomy or transpedicular). Pain and weakness were the most common presenting symptoms. Twenty-one thoracic disc herniations in 19 patients were available for long-term follow-up, averaging 58.1 months. Sixteen patients had an excellent or good result. Three patients had a fair result. There were no poor results. All six patients with significant preoperative lower extremity weakness improved. Pain was relieved in 16 patients and reduced in three. There were no significant neurologic complications associated with the procedure. Posterolateral decompression for thoracic disc herniation remains a viable alternative without the inherent risk and morbidity of the transthoracic approach.

Diskectomy↗

PubMed1993

Imaging anatomy of the lateral lumbar spinal canal.

This article reviews the normal anatomy of the bony and soft tissue structures of the lateral lumbar spinal canal. Thorough knowledge of these imaging anatomy helps in making the correct diagnosis of the lumbar spinal lesions. CT and MRI are excellent tools to diagnose lateral lumbar spinal canal stenosis. Both CT and MRI provide the accurate measurements of the midsagittal and lateral spinal canals and show the abnormalities of the nerve root course. This review provides anatomic and radiographic descriptions of the lateral lumbar spinal canal and the anatomically related joints.

Humans↗

PubMed1993

Nondiscogenic lumbar radiculopathy: imaging considerations.

This article reviews the differential diagnosis of lumbar radiculopathy, clinical presentations of spinal stenosis, pathological anatomy, and roentgenographic considerations of lumbar spinal stenosis. Most patients suspected of symptomatic spinal stenosis should have plain roentgenograms first to rule out other obvious lesions and to evaluate disc space and foraminal narrowing. Plain roentgenograms also show the sagittal and coronal deformities if present. The next procedure for the evaluation of spinal stenosis after plain roentgenograms should be MRI, as myelogram or CT can be avoided in most cases. In select cases, patients who cannot get MRI or those who underwent MRI with unresolved questions should have a myelogram or CT for further evaluation.

Diagnosis, Differential↗

PubMed1993

Upper lumbar disc herniations.

This study reviews the presentation, diagnosis, and outcomes of upper lumbar disc herniations (L1-2, L2-3, L3-4). One hundred forty-one patients operated upon at three centers between 1980 and 1990 were analyzed (102 men, 39 women; 3 L1-2, 21 L2-3, 117 L3-4; average age 51.6 years; 10.4% of all lumbar discectomies performed). Preoperative signs and symptoms were highly variable. Sensory, motor, and reflex testing was variable and potentially misleading in suggesting a level of herniation. In analyzing radiographic studies (noncontrast CT, myelography, MRI) individually and using other radiographic studies and operative findings as a standard for comparison, a high false-negative rate was found for all studies when considered individually, especially at the higher L2-3 level. Intraoperative radiographs were employed with increasing frequency as the level of herniation ascended. Six operative complications (4.3%) were identified, all of which were treated and were resolving at the time of discharge. Follow-up obtained at an average of 2.2 years in 87% of patients by chart review showed no reoperations or late complications. Noncompensation patients had a significantly higher percentage of good/excellent results (86%) than those with compensation or legal claims pending (45% good/excellent results). Based upon these data, we recommend myelogram with postmyelogram CT and/or MRI in the workup of these patients and intraoperative radiographs in all cases when decompressing an upper lumbar disc herniation. Patients with compensation/legal claims should be approached cautiously, because their subjective results are significantly worse than those of noncompensation patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Concomitant noncontiguous thoracolumbar and sacral fractures.

Seventeen patients were identified with concomitant thoracolumbar and sacral fractures representing 26% of sacral fractures and 7.7% of pelvic fractures. The thirteen men and four women exhibited a bimodal age distribution. There were thirteen vertical compression thoracolumbar fractures, three transverse process fractures, and one traumatic herniated nucleus pulposus. There were seven Zone I, seven Zone II, and three Zone III sacral fractures using the Denis classification. Five of the sacral fractures were missed on initial presentation. Four of the patients had neurogenic bowel or bladder symptoms. Seven of the thoracolumbar fractures and three of the sacral fractures were treated operatively. Results were generally good or excellent unless significant neurologic injury was present at initial presentation. The authors recommend aggressive computed tomographic evaluation of the sacrum in any suspicious pelvic trauma or when the neurologic lesion does not match the more proximal bony lesion. They hypothesize that decompression of both sacral and thoracolumbar lesions may be necessary if either lesion could be responsible for neurogenic bowel or bladder symptoms.

Adolescent↗