Three-dimensional characterization of in vivo intervertebral disc degeneration using EPIC-µCT.

OBJECTIVE: Small animal models are commonly employed to study progression of and potential treatment techniques for degenerative disc disease (DDD), but assessment using conventional imaging techniques is challenging due to resolution. The objective of this study was to employ equilibrium partitioning of an ionic contrast agent micro computed tomography (EPIC - µCT) to map three-dimensional (3D) degenerative changes in the rabbit intervertebral disc (IVD). MATERIALS AND METHODS: In vivo degeneration was induced surgically in 12 New Zealand White rabbits via percutaneous annular puncture and percutaneous nucleotomy. IVDs were harvested after 3 and 6 weeks. EPIC-µCT imaging was performed on fresh, IVDs before and after formalin fixation, and 3D IVD volumes were segmented. IVDs were histologically stained with Safranin-O/Fast-Green and Hematoxylin & Eosin (H&E). EPIC-µCT attenuation and 3D morphological measurements were assessed in healthy and degenerate IVDs and compared to qualitative grading and disc height measurement from histology. RESULTS: EPIC-µCT caused pronounced contrast enhancement of the IVD. Annular puncture and nucleotomy produced mild and severe degenerative changes, respectively. IVD attenuation following contrast enhancement increased significantly in nucleotomized discs at 3 and 6 weeks. IVD attenuation correlated significantly with histologic score and disc height measurements. Disc height decreased most extensively in the posterior and lateral aspects of the IVD. 3D morphological measurements correlated strongly to IVD attenuation and were more sensitive to degenerative changes than histologic measurements. Formalin fixation reduced the attenuation of IVDs by ∼10%. CONCLUSION: EPIC-µCT is sensitive to in vivo DDD induced by nucleotomy and provides a high resolution 3D method for mapping degenerative changes in rabbit IVDs.

Risk factors for spinal epidural hematoma after spinal surgery.

STUDY DESIGN: A case-control retrospective analysis comparing patients who developed a postoperative spinal epidural hematoma with patients who did not develop this complication. OBJECTIVES: To identify risk factors for the development of an epidural hematoma following spinal surgery. SUMMARY OF BACKGROUND DATA: Neurologic deterioration following spinal surgery is a rare but devastating complication. Epidural hematomas should be suspected in the patient who demonstrates a new postoperative neurologic deficit. The risk factors that predispose a patient to a postoperative spinal epidural hematoma have not been identified. METHODS: Patients who underwent spinal surgery at a single institution over a 10-year period were retrospectively reviewed. Twelve patients who demonstrated neurologic deterioration after surgery and required surgical decompression because of an epidural hematoma were identified. All cases involved lumber laminectomies. A total of 404 consecutive patients that underwent lumbar decompression and did not develop an epidural hematoma formed the control group. Factors postulated to increase the risk of postoperative spinal epidural hematoma were compared between the two groups using logistic regression. RESULTS: Multilevel procedures (P = 0.037) and the presence of a preoperative coagulopathy (P < 0.001) were significant risk factors. Age, body mass index, perioperative durotomies, and postoperative drains were not statistically significant risk factors. CONCLUSIONS: Patients who require multilevel lumbar procedures and/or have a preoperative coagulopathy are at a significantly higher risk for developing a postoperative epidural hematoma.

Anterior cervical interbody fusion with rhBMP-2 and tantalum in a goat model.

BACKGROUND CONTEXT: Tricortical autogenous iliac crest has long served as the gold standard for arthrodesis after cervical discectomy. The added morbidity resulting from bone graft harvest may be eliminated by the use of a biocompatible synthetic bone graft substitute with osteoconductive abilities, and when used with an osteoinductive agent, such as recombinant bone morphogenic protein (rhBMP)-2, it may facilitate arthrodesis similar to autograft. PURPOSE: To determine by radiographic and histologic analysis whether tantalum with and without rhBMP-2 can facilitate bony ingrowth and arthrodesis in an animal model. STUDY DESIGN/SETTING: Single-level anterior cervical discectomy and fusion was performed using a tantalum bone graft substitute with and without rhBMP-2 in a previously established goat model for anterior cervical fusion. METHODS: Eight goats underwent single-level anterior cervical discectomy and stabilization with a porous tantalum implant. There were four goats in each experimental group. Group A underwent anterior cervical stabilization with tantalum alone, whereas in Group B rhBMP-2 was added to the tantalum implant. The goats were sacrificed at 12 weeks, and their cervical spines were removed for histologic and radiological analysis. RESULTS: Only one of four goats in Group A had any bony ingrowth into the tantalum. Three of four goats in Group B demonstrated bony ingrowth. The average extent of bony ingrowth at the perimeter of the tantalum in Group A was 2.5% compared with 12.5% in Group B. Similarly, the volume of bony ingrowth within the tantalum was 2.5% in Group A and 10% in Group B. The difference was not statistically significant. CONCLUSIONS: The data in this pilot study suggest that tantalum may function as a synthetic osteoconductive bone graft substitute. The addition of rhBMP-2 may facilitate osteoinduction within a synthetic osteoconductive implant. The sample size in this study was too small for statistical significance. The present animal model as used in this study was inadequate for cervical arthrodesis where rigid implant fixation is desired.

Perspectives on modern orthopaedics: use of Adcon-L for epidural scar prevention.

Adcon-L is a biodegradable gel matrix that was recently approved by the Food and Drug Administration for use during single-level posterior lumbar laminectomy or laminotomy procedures. Experimental and clinical studies have suggested that the use of this product will decrease postoperative epidural scarring. However, the relationship between epidural fibrosis and patient outcome remains unclear. If the treating surgeon is of the opinion that there is a need to reduce epidural scar, the use of this product appears worthwhile. However, further studies are needed to evaluate clinical outcome and justify the use of this product on a routine basis.

Complication, survival rates, and risk factors of surgery for metastatic disease of the spine.

STUDY DESIGN: The risk factors for complications and complication and survival rates in patients with metastatic disease of the spine were reviewed. A retrospective study was performed. OBJECTIVES: To determine the surgical complication and survival rates of patients with metastatic disease of the spine and risk factors for complication occurrence. SUMMARY OF BACKGROUND DATA: The role of surgical intervention for patients with metastatic disease of the spine has been controversial. Several risk factors for surgical complications have been identified. Short survival times and high complication rates have failed to justify surgical intervention in many cases. METHODS: Patients (n = 80) undergoing surgical treatment for metastatic disease of the spine were reviewed. Surgical indications included progressive neurologic deficit, neurologic deficit failing to respond to, or progressing after, radiation treatment; intractable pain; radioresistant tumors; or the need for histologic diagnosis. Patients underwent anterior, posterior, or combined decompression and stabilization procedures. Neurologic examination was recorded before surgery, postoperative period, and at least follow-up. Complication and survival rates were calculated. Several variables were examined for risk of complication. RESULTS: The mean age at time of surgery was 55.6 years (range, 20-84 years). Mean survival time after the diagnosis of spinal metastasis was 26.0 months (range, 1-107.25 months). Mean survival time after surgery was 15.9 months (range, 0.25-55.5 months). Sixty-five patients showed no change in Frankel grade, 19 improved one Frankel grade, and 1 deteriorated one Frankel grade; 1 patient had paraplegia. Thirty-five complications occurred in 20 patients (25.0%). Ten patients (12.5%) had multiple complications accounting for 23 of the 35 postoperative problems (65.7%). Sixty patients had no surgical complications (75%). There were no intraoperative deaths. CONCLUSIONS: The likelihood that a complication occurred was significantly related to Harrington classifications demonstrating significant neurologic deficits and the use of preoperative radiation therapy. In general, Harrington classifications with neurologic deficits and lower Frankel grades before and after surgery were associated with an increased risk of complication. Overall, the major complication rate was relatively low, and minor complications were successfully treated with minimal morbidity. The relatively long survival time after spinal surgery in this group of patients justifies surgical treatment for metastatic disease. Most complications occurred in a small percentage of patients. To minimize complications, patients must be carefully selected based on expected length of survival, the use of radiation therapy, presence of neurologic deficit, and impending spinal instability or collapse caused by bone destruction.

The use of recombinant human bone morphogenetic protein 2 (rhBMP-2) to promote spinal fusion in a nonhuman primate anterior interbody fusion model.

STUDY DESIGN: A study on the efficacy of recombinant human bone morphogenetic protein 2 (rhBMP-2) in a nonhuman primate anterior interbody fusion model. OBJECTIVES: To investigate the efficacy of rhBMP-2 with an absorbable collagen sponge carrier to promote spinal fusion in a nonhuman primate anterior interbody fusion model. SUMMARY OF BACKGROUND DATA: RhBMP-2 is an osteoinductive growth factor capable of inducing new bone formation in vivo. Although dosage studies using rhBMP-2 have been performed on species of lower phylogenetic level, they cannot be extrapolated to the primate. Dosage studies on nonhuman primates are essential before proceeding with human primate application. METHODS: Six female adult Macaca mulatta (rhesus macaque) monkeys underwent an anterior L7-S1 interbody lumbar fusion. All six sites were assigned randomly to one of two fusion methods: 1) autogenous bone graft within a single freeze-dried smooth cortical dowel allograft cylinder (control) or 2) rhBMP-2-soaked absorbable collagen sponges within a single freeze-dried smooth cortical dowel allograft cylinder also soaked in rhBMP-2. The animals underwent a baseline computed tomography scan followed by 3- and 6-month postoperation scans. Anteroposterior and lateral radiographs of the lumbosacral spine were performed monthly. After the monkeys were killed, the lumbar spine fusion sites were evaluated. Histologic evaluation of all fusion sites was performed. RESULTS: The three monkeys receiving rhBMP-2-soaked collagen sponges with a freeze-dried allograft demonstrated radiographic signs of fusion as early as 8 weeks. The control animals were slower to reveal new bone formation. The computed tomography scans revealed extensive fusion of the L7-S1 lumbar vertebrae in the group with rhBMP-2. A pseudarthrosis was present in two of the control animals. CONCLUSIONS: This study was able to document the efficacy of rhBMP-2 with an absorbable collagen sponge carrier and a cortical dowel allograft to promote anterior interbody fusion in a nonhuman primate model at a dose of 0.4 mg per implant site (1.5 mg/mL concentration). The late of new bone formation and fusion with the use of rhBMP-2 and cortical dowel allograft appears to be far superior to that of autogenous cancellous iliac crest graft with cortical dowel allograft.

Computed tomography-guided biopsy of the spine. A review of 103 patients.

STUDY DESIGN: A retrospective study of 103 computed tomography-guided biopsies of the spine. These represent a consecutive series of patients with spinal lesions or disorders observed over a 32-month period. OBJECTIVES: To determine the diagnostic accuracy and clinical usefulness of computed tomography-guided biopsies with respect to major influencing variables. SUMMARY OF BACKGROUND DATA: Computer tomographic-guided biopsy of the spine is considered a safe, accurate, and relatively inexpensive examination technique. A study comparing its diagnostic accuracy with respect to all the variables of age, gender, radiographic appearance, spinal level, tissue type, or pathologic diagnosis has not been done. METHODS: Biopsy specimens were sent for cytologic and histologic analysis. Bacteriologic studies were performed when clinically indicated. The biopsy results were analyzed for adequacy and diagnostic accuracy, i.e., the ability to generate a tissue sample adequate for pathologic examination and one that yields diagnostic information. RESULTS: The mean age of patients was 60 years, with a range of 4-91 years. The spines of 52 males and 51 females were studied. There were eight cervical, 28 thoracic, 53 lumbar, and 14 sacral lesions used as biopsy sites. The radiographic appearance of spinal lesions were lytic in 74 cases, blastic in four cases, and mixed in two cases. Tissues undergoing biopsy included bone (63 cases), soft tissue (35 cases), and mixed specimens (five cases). The pathologic examinations revealed 18 infections, 23 primary neoplasms, 34 metastases, and 19 normal tissues. An adequate specimen for pathologic examination was obtained in 90 biopsies (87%). A diagnosis was achieved in 67 of 94 patients (71%). Diagnostic rates obtained in thoracic level biopsies were lower than those from biopsies of other spinal levels (P = .007). CONCLUSION: Computed tomography-guided biopsy is an important tool in the evaluation of spinal lesions. A positive biopsy result may preclude the need for open surgical intervention. This study included one of the largest series of patients in the medical literature. In addition, it determined the diagnostic rates of this procedure with respect to the major influencing variables. Thoracic-level biopsies have a diagnostic rate that is significantly lower than that of other spinal levels. No significant correlation was found between diagnostic accuracy and age, gender, radiographic appearance, tissue type, or eventual diagnosis.

Traumatic bilateral rotatory dislocation of the atlanto-axial joints: a case report and review of the literature.

Traumatic bilateral rotatory dislocation at the atlanto-axial joints is a rare injury in adults. Only three prior cases have been reported (1,2,3). Our case report, review of management, and pathophysiology from the literature is presented. This injury may be successfully treated by closed reduction and brace immobilization.

1997 Volvo Award winner in clinical studies. Degenerative lumbar spondylolisthesis with spinal stenosis: a prospective, randomized study comparing decompressive laminectomy and arthrodesis with and without spinal instrumentation.

STUDY DESIGN: This prospective study analyzed the influence of transpedicular instrumented on the operative treatment of patients with degenerative spondylolisthesis and spinal stenosis. OBJECTIVES: To determine whether the addition of transpedicular instrumented improves the clinical outcome and fusion rate of patients undergoing posterolateral fusion after decompression for spinal stenosis with concomitant degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: Decompression is often necessary in the treatment of symptomatic patients who have degenerative spondylolisthesis and spinal stenosis. Results of recent studies demonstrated that outcomes are significantly improved if posterolateral arthrodesis is performed at the listhesed level. A meta-analysis of the literature concluded that adjunctive spinal instrumentation for this procedure can enhance the fusion rate, although the effect on clinical outcome remains uncertain. METHODS: Seventy-six patients who had symptomatic spinal stenosis associated with degenerative lumbar spondylolisthesis were prospectively studied. All patients underwent posterior decompression with concomitant posterolateral intertransverse process arthrodesis. The patients were randomized to a segmental transpedicular instrumented or noninstrumented group. RESULTS: Sixty-seven patients were available for a 2-year follow-up. Clinical outcome was excellent or good in 76% of the patients in whom instrumentation was placed and in 85% of those in whom no instrumentation was placed (P = 0.45). Successful arthrodesis occurred in 82% of the instrumented cases versus 45% of the noninstrumented cases (P = 0.0015). Overall, successful fusion did not influence patient outcome (P = 0.435). CONCLUSIONS: In patients undergoing single-level posterolateral fusion for degenerative spondylolisthesis with spinal stenosis, the use of pedicle screws may lead to a higher fusion rate, but clinical outcome shows no improvement in pain in the back and lower limbs.

Augmentation of autograft using rhBMP-2 and different carrier media in the canine spinal fusion model.

This study evaluated the use of recombinant human bone morphogenetic protein (rhBMP-2) with various types of carrier media, and the effect of rhBMP-2 as an adjunct to autogenous iliac crest bone graft in the canine spinal fusion model. BMP induces mesenchymal cells to differentiate into cartilage and bone. The recent availability of rhBMP-2 has created the opportunity to evaluate this material's properties in augmenting autogenous bone graft in spinal fusion. Currently, the most appropriate type of carrier media for rhBMP-2 is undetermined. Bilateral intertransverse spinal fusions were performed on six canine lumbar spines at L1-L2, L3-L4, and L5-L6, using autogenous posterior iliac crest bone graft at each level, creating a total of 18 segmental fusion sites. All 18 sites were then randomly assigned to one of six fusion methods: autogenous bone graft (ABG) alone, ABG + rhBMP-2, ABG + collagen (Helistat) "sandwich" + rhBMP-2, ABG + collagen (Helistat) morsels + rhBMP-2, ABG + polylactic/glycolic acid sponge (PLGA) sandwich + rhBMP-2, and ABG + open-pore polylactic acid morsels + rhBMP-2. Each material was evaluated for ease of handling and application at the index surgery. The animals underwent computed tomography (CT) scanning of the lumbar fusion sites after 8 weeks. Volumetric measurements of total fusion mass at each level were performed using two-dimensional CT scan slices and a volumetric program supplied by the Siemens Medical System. The animals were killed after imaging studies. The lumbar spine fusion sites were evaluated for integrity of the fusion mass, both visually and with manual mechanical stressing. Crossover of the fusion mass to adjoining levels was also evaluated. Histologic evaluation of all fusion sites was performed. The addition of rhBMP-2 significantly increased bone graft volume as noted on CT scan. Carrier that could be mixed with morselized bone graft offered easier handling and application and all spine segments fused. Polylactic/glycolic acid (PLGA) sites were associated with a greater incidence of voids within the fusion mass. No significant difference in carrier media for rhBMP-2 could be determined. However, PLGA was associated with a higher rate of fusion mass void formation. rhBMP-2, when added to autograft, significantly increased the volume and the maturity of the resulting fusion mass.

Efficacy of closed wound suction drainage after single-level lumbar laminectomy.

The use of closed suction drainage after spinal surgery remains controversial. The purpose of this study was to determine the indications for closed suction drainage after single-level lumbar surgery. Two hundred patients who were scheduled to undergo single-level lumbar surgery without fusion were prospectively randomized into two groups. One group had a closed wound suction drain placed deep to the lumbodorsal fascia before routine closure, whereas the second group had no drain placed. Hemostasis was achieved in all patients before the surgeon had knowledge of the randomization outcome. All drains were removed on the 2nd postoperative day, and the amount of drainage was recorded. After surgery, the patients were evaluated for signs and symptoms of continued wound drainage, hematoma/seroma formation, and/or infection as well as evidence of an acquired neurologic deficit. One hundred three patients had a drain placed before closure and two patients developed postoperative wound infection, both of which were successfully treated with orally administered antibiotics. Of the 97 patients who had no drain placed after the surgical procedure, one patient developed a postoperative wound infection that was treated with surgical incision and drainage, as well as intravenously administered antibiotics. Statistical analysis revealed that the presence or absence of a drain did not affect the postoperative infection rate. No new neurologic deficits occurred in any postoperative patient. The use of drains in single-level lumbar laminectomy without fusion did not affect patient outcome. There was no significant difference in the rate of infection or wound healing and no patient developed a postoperative neurologic deficit.

Is pathology examination of disc specimens necessary after routine anterior cervical discectomy and fusion?

STUDY DESIGN: A retrospective chart review was performed from 1990-1994. OBJECTIVES: To evaluate the outcome of pathologic examination of cervical disc specimens submitted after anterior cervical discectomy. SUMMARY OF BACKGROUND DATA: This study is the first to review the outcome of pathologic examination of disc specimens after anterior cervical discectomy and fusion. METHODS: Charts were reviewed based on the procedure code of anterior cervical fusion and the main diagnoses of cervical disc and spondylosis. The following data were recorded for each patient: symptoms, examination, diagnostic studies, operative procedure, operative findings, and pathology report. Statistical analysis was performed. RESULTS: Five hundred six disc levels in 394 patients were reviewed. All patients had symptoms and examination results consistent with cervical radiculopathy. All patients had cervical radiographs and some combination of myelography, computed tomography, or magnetic resonance imaging. Findings at the time of surgery included the presence of either a herniated disc or degenerative spondylitic changes. The pathologic examination results of all specimens reported fibrocartilaginous tissue consistent with disc material with the presence of degenerative changes. No infectious, benign, or malignant process was identified at the time of surgery or on gross and histologic examination of any of the disc specimens. Using confidence intervals (95%) for exact proportions and given 500 negatives, the chance the next occurrence would be positive would be 0.0060 or 0.60% or six of 1000. CONCLUSIONS: This study shows that if the symptoms, physical examination, radiographic diagnostic studies, and surgical findings are consistent with those of cervical disc herniation of spondylosis, the chance of an unexpected, clinically important pathologic finding within the disc specimen is extremely small. The time and expense involved in routine pathologic examination of cervical disc specimens can be avoided.

The effect of interposition membrane on the outcome of lumbar laminectomy and discectomy.

STUDY DESIGN: This study evaluated clinical and magnetic resonance imaging differences of patients treated surgically for lumbar disc herniation. Clinical follow-up and magnetic resonance imaging evaluation of epidural fibrosis were used to assess patient outcome. OBJECTIVES: The purpose of this study was to evaluate the difference in clinical outcome with either free-fat graft, Gelfoam, or no interposition membrane placed in the laminectomy defect after nerve root decompression. SUMMARY OF BACKGROUND DATA: Epidural fibrosis has been considered a cause of recurrent symptoms after lumbar laminectomy, and numerous materials have been evaluated for prophylaxis of the "laminectomy membrane." These have been mainly histologic and animal studies with no data correlating clinical symptoms and postoperative epidural scar formation. METHODS: One hundred fifty-six patients who were treated surgically for lumbar disc herniation were randomly assigned to one of three groups and followed prospectively for at least 1 year. Thirty-three of these patients were received magnetic resonance imaging evaluations after 6 months by an independent radiologist who graded the amount of epidural scar formation. The patients were assessed at 1 year and given a rating of excellent, good, fair, or poor, and the scar was graded as none, minimal, or moderate. RESULTS: Although 97% of all patients improved, 83% were rated excellent or good. There were no statistical differences between the three groups clinically and radiographically. Patients with workers compensation had a statistically significant lower success rate (P < 0.001). CONCLUSIONS: Clinical outcome after lumbar disc surgery does not correlate with the use or type of interposition membrane used to prevent epidural fibrosis.

Passive reduction of spondylolisthesis on the operating room table: a prospective study.

Translational motion of low-grade spondylolisthesis is traditionally assessed with lateral flexion and extension radiographs. Maximum motion in an unanesthetized patient may be limited by patient cooperation, pain, or muscle spasm. Twenty-four patients with degenerative or isthmic spondylolisthesis were assessed with preoperative lateral flexion and extension radiographs. A lateral radiograph was obtained on the operating room table after administering an anesthetic, exposing the spine, and performing a laminectomy. The percentage slip decreased from 24 to 15 to 6% on flexion, extension, and intraoperative lateral radiographs, respectively (p < 0.001). The amount of reduction did not correlate with disc height, slip angle, slip level, or type of spondylolisthesis. Many low-grade spondylolisthesis deformities reduce almost completely on the operating table. Translational motion of spondylolisthesis is greater than preoperative flexion and extension radiographs indicate.

Variables affecting time to bone healing during limb lengthening.

Radiographs and charts of 114 consecutive patients who underwent 140 lower-extremity bone-segment lengthening procedures using the Ilizarov external fixator were reviewed. Patient age, bone segment (femur, tibia), corticotomy level (metaphyseal, diaphyseal, double level), and distraction gap (DG) were recorded. Distraction-consolidation time (DCT) was defined as the interval in months from the date of the corticotomy until the DG was healed according to radiographic and manual testing criteria. Distraction-consolidation time had a direct linear relationship with the magnitude of the DG. Distraction--consolidation time versus DG was significantly less for femoral than tibial lengthening. Patients 20 years and older healed slower than patients younger than the age of 20 years. Patients 20 to 29 years old healed faster than patients older than 30 years and slower than patients younger than 20 years. Diaphyseal lengthening healed more slowly than metaphyseal lengthening. Double-level lengthening reduced the DCT when the DG was greater than 4 cm. Distraction--consolidation index--DCT divided by DG--was not a constant. Distraction--consolidation index decreased with increasing DG. To facilitate prediction of bone-healing time, graphs were developed demonstrating the average treatment time +/- 2 SD expected for a specific amount of lengthening, considering the bone segment, the level of osteotomy, and the age of the patient.

Malignant degeneration of a vertebral osteochondroma with epidural tumor extension: a report of the case and review of the literature.

A case involving spinal cord compression due to local extension of vertebral chondrosarcoma is described. The malignancy originated in an osteochondroma and spread via the epidural veins. Surgical staging as well as options for the treatment of vertebral chondrosarcoma are discussed.

Open reduction and circular external fixation of intraarticular calcaneal fractures.

Open reduction and internal fixation techniques do not allow early weight bearing. In an effort to develop a better method to obtain calcaneal fracture reduction and maintain it in the face of early weight bearing, a circular external fixator was applied to seven patients in combination with a limited lateral approach and open reduction and internal fixation of the depressed subtalar joint fragments. The operative technique uses the Ilizarov circular external fixator to obtain a ligamentotaxis reduction, following which the depressed subtalar joint fragments are elevated open; then, the fixator is used to reduce the lateral translation. All displacements of the fracture fragments are corrected. This method proved successful in six patients, all of whom achieved a satisfactory result with anatomic restoration of the subtalar joint and heel. One patient went on to late partial collapse of the posterior facet. Subtalar motion was greater than 50% in four of seven patients. None of the patients complained of heel pad pain, which was attributed to the desensitization of the heel by early weight bearing. This technique has produced encouraging preliminary results in two- to four-year follow-up evaluation.

Diagnosis and treatment of discogenic low back pain.

Low back pain (LBP) is very prevalent in the general population. Treatment of nonradicular back pain, in the absence of deformity, continues to be controversial. Recently, anatomic dissections, magnetic resonance imaging studies, and the use of provocative discograms (pain-related response during the injection similar to the typical pattern of pain reported prior to the procedure) have contributed to our understanding of the etiology of discogenic back pain. Various techniques of spine fusion, with and without instrumentation, have altered the natural history of LBP unresponsive to conservative treatment. This review discusses the etiology and diagnosis of discogenic back pain and the treatment options available to the spine surgeon.

Deaf children from ethnic, linguistic and racial minority backgrounds: an overview.

Deaf children from ethnic, linguistic and racial minority backgrounds demonstrate significantly depressed achievement levels relative to their White deaf peers. Educators of deaf children and youth have had a tendency to accept the erroneous proposition that deafness in some ways precludes ethnic and racial minority group membership and status. This article describes some of the unique social and educational realities faced by Black and Hispanic children and their families in the northeastern United States and the similarities experienced by deaf Black and Hispanic children and their families. Implications concerning educational assessment, placement, student expectations, curriculum development, staffing and policy making are noted as are recommendations that resulted from the first national conference on Black and Hispanic deaf youth held in March 1989. Demographic data are also presented showing the growth and distribution in the population of minority deaf children, as well as the results of a survey indicating the dearth of minority personnel, board members and specialized programs in schools.