Outcome analysis of noninstrumented anterior cervical discectomy and interbody fusion in 348 patients.

STUDY DESIGN: Twenty-one outcome and outcome-relevant variables (fusion and patient satisfaction) were evaluated in a subset of 348 of 514 patients operated on by one surgeon during a 22-year period, using Cloward's anterior cervical discectomy and dowel interbody fusion. Minimum patient follow-up was 2 years; average length of follow-up was 5.2 years. This retrospective analysis is accompanied by a comprehensive review of the literature (1975-1996) of noninstrumented anterior cervical fusions, excluding fibular grafts alone in the interbody space. OBJECTIVES: To provide data on outcome (with regard to patient satisfaction and radiologically supported fusion) and risks of noninstrumented anterior cervical discectomy and fusion for intractable cervical nerve root and spinal cord compression symptoms at single or multiple levels, using the results from a single surgeon. METHODS: Three experienced spine radiologists determined fusion rates in one to five levels in 348 patients on the basis of the results of plain film analysis. Patient self-assessment was used to determine degree of patient satisfaction and other related variables. From a comprehensive review of the literature, 43 clinical reports meeting requirements for comparison of findings with those in the current study were selected from more than 1600 reports. RESULTS: The mean fusion rate for 348 patients in the current study ranged from 75% (multilevel) to 88% (one level; n = 202). The overall fusion rate was 83%. The persistent complication rate was 0.1%, and patient self-assessments showed that 78% were satisfied with the outcome and that 83% returned to work. The overall fusion rate for 2037 patients evaluated in the comprehensive literature review is 92%. CONCLUSIONS: Results of this study indicate that better outcome in noninstrumented anterior cervical discectomy and fusion is associated with solid fusion, fewer fused levels, nonsmoking patients, higher education levels, and absence of secondary economic gain. There was no correlation between fusion status and bone graft source or use of cervical collar.

Acute spinal ligament disruption: MR imaging with anatomic correlation.

Disruption of spinal ligaments can lead to instability that jeopardizes the spinal cord and nerve roots. Magnetic resonance (MR) imaging can directly image spinal ligaments; however, the sensitivity with which this modality demonstrates ligament injury has, to the authors' knowledge, not been reported. On a biomechanical testing machine, 28 cadaveric spines were subjected to controlled injury that resulted in ligament tears. The spines were then imaged with plain radiography, computed tomography, and MR imaging (1.5 T). The images were analyzed for evidence of ligament injury before dissection of the specimen. Forty-one of 52 (79%) ligament tears of various types were correctly identified at MR imaging. Disruptions of the anterior and posterior longitudinal ligaments were most conspicuous and were detected in all seven cases in which they were present (no false-positive or false-negative results); disruptions of the ligamentum flavum, capsular ligaments, and interspinous ligaments could also be identified but less reliably (three false-positive and 11 false-negative results). That MR imaging can reliably and directly allow assessment of spinal ligament disruption in this in vitro model suggests its potential utility for this assessment in patients.

Detection of migratory silicone pseudotumor with use of magnetic resonance imaging.

A patient with silicone gel breast implants, who experienced capsular contracture of the left breast that was treated by closed capsulotomy, sought medical attention because of numbness and pain in the left medial forearm and hand. Inflammatory masses subsequently developed in the left anterior axillary and antecubital regions. Magnetic resonance imaging revealed silicone pseudotumors, and mammography confirmed implant rupture and gel extrusion along fascial planes into the axillary region.

Radiographic and geometric anatomy of the scapula.

In an effort to study anatomic parameters of the scapula that may be of clinical importance, scapulae were harvested from cadavers and stripped of their soft tissues. For each scapula, three roentgenograms then were obtained: a Y-scapular view, an axillary lateral view, and a glenoid fossa (or true anteroposterior) view. Computed tomographic pneumoarthrograms and randomly selected antero-posterior chest roentgenograms of skeletally mature adults were studied also to measure further roentgenographic parameters of the normal scapula. The geometric anatomy of the scapula is of fundamental importance in the pathomechanics of rotator cuff disease, total shoulder arthroplasty, and recurrent shoulder dislocation. This study presents in detail the exact geometry of scapula anatomy, giving precise figures for distances, angles, and radii of curvature of the scapula. All results then are discussed in terms of their clinical relevance to the above problems.

The "numb cheek-limp lower lid" syndrome.

A patient developed isolated numbness, 1st confined to the lateral nose and upper lip, but later involving the cheek, lower lip, upper gingiva, and the palate. This numbness was later associated with paresis of the muscles of the upper lip and angle of the mouth and with ipsilateral lower lid droop (the "numb cheek-limp lower lid" syndrome). Squamous cell carcinoma was discovered infiltrating the infraorbital nerve and distal branches of the facial nerve. Cheek numbness associated with lower eyelid or upper lip weakness may herald a neoplasm affecting the infraorbital nerve and distal facial nerve branches.

X-linked hypophosphatemic rickets without "rickets".

Wrist and knee radiographs from children with X-linked hypophosphatemic rickets were analyzed and compared with those from normal children and children with established rickets to assess whether radiographically apparent rickets is a consistent abnormality in X-linked hypophosphatemia. The absence or presence of rickets was correctly identified in 94.8% of wrist and knee films from normal and positive controls. In contrast, patients with X-linked hypophosphatemia exhibited rachitic abnormalities in only 5 of 11 wrist and 13 of 15 knee radiographs. As a result, 4 patients within this study group had rickets at the knee and not at the wrist, whereas 5 displayed classic defects at both sites. Perhaps more important, 2 patients, aged 3.8 and 5.2 years, displayed no evidence of rickets in either wrist or knee films, although relatives exhibited demonstrable rachitic abnormalities. Our data indicate that radiographically detectable rickets is a variable abnormality of X-linked hypophosphatemia and does not provide an unambiguous index for the diagnosis of this disease.

Aluminum-induced neo-osteogenesis: a generalized process affecting trabecular networking in the axial skeleton.

To determine if aluminum-induced neo-osteogenesis occurs in the axial skeleton, we compared spinal bone density and vertebral histology of beagles treated with aluminum for 8 and 16 weeks to that of untreated normals. Administration of aluminum (1.25 mg/kg) did not alter serum calcium, phosphorus, or creatinine but did result in a significant elevation of vertebral bone density, measured by quantitative computed tomography, after both 8 (286.7 +/- 12.4 mg/ml) and 16 (361.7 +/- 46.5 mg/ml) weeks of treatment compared with controls (212.2 +/- 4.5 mg/ml). In accord with the increased bone density, biopsies from the spine displayed evidence of neo-osteogenesis, including the presence of woven bone, both mineralized and unmineralized, within the marrow space. The genesis of such woven bone units resulted after 16 weeks in a significant increase in trabecular bone volume, woven and lamellar (51.2 +/- 4.4 versus 32.4 +/- 1.2%; p less than 0.05), woven bone volume (9.1 +/- 3.6 versus 0 +/- 0%; p less than 0.05), and trabecular number (4.5 +/- 0.3 versus 3.5 +/- 0.2 per mm; p less than 0.05). In addition, scanning electron microscopic evaluation of the bone biopsies confirmed the existence of new trabecular plates that provided interconnections between existent units. These observations illustrate that aluminum-induced neo-osteogenesis positively influences trabecular networking in the axial skeleton. Such enhancement of bone histogenesis contrasts with the effects of other pharmacologic agents that solely alter the thickness of existing trabecular plates or rods within the vertebral spongiosa.

Cervical spondylolysis: imaging findings in 12 patients.

Cervical spondylolysis is defined as a corticated cleft between the superior and inferior articular facets of the articular pilar, the cervical equivalent of the pars interarticularis in the lumbar spine. Associated dysplastic changes and spina bifida suggest that the lesion is congenital. It is a rare condition; only 70 cases have been previously reported in the world literature. Recognition of this disorder and differentiation from traumatic articular pilar fracture or dislocation is of paramount importance in patients who have had cervical spine trauma. The present study details radiologic features in 12 patients 20-80 years old with cervical spondylolysis. Plain film radiologic findings were correlated with hypocycloidal high-resolution tomography (nine patients), CT (six patients), and MR imaging (one patient). Seven patients had spondylolysis at C6 (three bilateral) and five had the abnormality at C4 (all unilateral). Nine of 12 patients were initially misdiagnosed. Characteristic radiologic features include (1) a well-marginated cleft between the facets, (2) a triangular configuration of the pilar fragments on either side of the spondylolytic defect, (3) posterior displacement of the dorsal triangular pillar fragment, (4) hypoplasia of the ipsilateral pedicle, (5) spina bifida at the involved level, and (6) compensatory hyper- or hypoplasia of the ipsilateral articular pillars at the level above and/or below the defect. A multistudy approach was often necessary to demonstrate these findings. Heightened awareness of the radiologic features of cervical spondylolysis should allow one to differentiate it from articular pillar fracture or dislocation.

Imaging of tumoral calcinosis: new observations.

Five patients with tumoral calcinosis were evaluated with radiography, bone scintigraphy, computed tomography (CT), and magnetic resonance (MR) imaging. The arthropathy of calcium pyrophosphate dihydrate deposition disease was seen in two of the patients and pseudoxanthoma elasticum-like syndrome in three. Identification of calcific particular masses on radiographs is characteristic of tumoral calcinosis. Marrow lesions could be identified as patchy areas of calcification (calcific myelitis) in long bones and the calvarium. Bone scintigraphy appears to be the best modality for detection of the masses and marrow lesions and for monitoring therapy. At CT the masses demonstrated a varied appearance, from small and solid to large and cystic. The marrow abnormality appears as an area of increased attenuation and spotty calcification that in the skull may be associated with dural and vascular calcifications. MR imaging of the particular masses was remarkable in that the masses displayed high signal intensity on T2-weighted images despite a large calcific component. Marrow lesions also showed increased signal intensity on T2-weighted images. When calcified particular masses are present the diagnosis is rarely in question. The diagnosis may be overlooked, however, when calcific myelitis is the only manifestation.

Computed tomography of hamstring muscle strains.

Acute hamstring muscle strains occurring in ten college athletes were evaluated using computed tomography to identify the location and characteristics of these common injuries. Acute muscle strains appeared as areas of hypodensity within the muscle 1-2 d following injury. This suggests that inflammation and edema are the major component of injury, not bleeding as commonly assumed. Injuries were seen most commonly in the proximal and lateral portions of the hamstring muscle group, particularly in the biceps femoris.

Herniation pits of the femoral neck: appearance at MR imaging.

Herniation pits of the femoral neck are benign lesions recognized because of their characteristic appearance and location on plain radiographs. The appearance of this lesion in seven magnetic resonance (MR) examinations of the hips in five patients is described. MR revealed a well-marginated, round to oval defect in the superior lateral quadrant of the femoral neck with anterior cortical extension in all cases. With T1 weighting the signal intensity within each lesion was uniformly low. All but one case revealed a peripheral margin of absent signal intensity on T2-weighted and out-of-phase images. The MR appearance and location are sufficiently characteristic to allow identification of this lesion and aid in differentiating it from pathologic processes such as avascular necrosis, with which it may be confused.

Synovial chondromatosis of the temporomandibular joint diagnosed by magnetic resonance imaging: report of a case.

A case of synovial chondromatosis of the temporomandibular joint with extracapsular extension is described. Temporomandibular joint magnetic resonance imaging proved invaluable in establishing a definitive diagnosis.

Correlation of magnetic resonance imaging and surgical findings in patients with meniscal perforation.

Advancement of surgical techniques has made it necessary to accurately diagnose internal derangements. Arthrography and computerized tomography have been used to diagnose the majority of temporomandibular joint disorders; however, these methods have had their disadvantages. Magnetic resonance imaging utilizing surface coils has greatly improved the ability to diagnose meniscus abnormalities without using interarticular injections or ionizing radiation. Ninety-two patients (184 joints) were evaluated by means of magnetic resonance imaging (MRI). Thirty-one patients (39 joints) were diagnosed as having meniscus perforation. Retrospective reviews of 15 patients (20 joints) with a perforated meniscus diagnosed by magnetic resonance imaging preoperatively demonstrated a 65% correlation between the radiographic diagnosis and the surgical findings.

Long-term marginal zinc deprivation in rhesus monkeys. IV. Effects on skeletal growth and mineralization.

Skeletal maturation was evaluated from ages 1 to 3 y in rhesus monkeys that had been subjected to a diet marginally deficient in zinc (4 micrograms/g Zn) from conception through age 3 y. Skeletal development was assessed at 18, 24, 30, and 36 mo of age and compared with that of controls fed ad libitum. Skeletal maturation was determined by the presence of epiphyseal ossification centers. To evaluate endochondral bone mineralization the appearance of the zone of provisional calcification on the metaphyseal side of the growth plate and the width of the growth plate were observed. Marginal Zn deprivation was associated with delayed skeletal maturation in monkeys up to age 3 y. Defective mineralization of bone was evident in these monkeys up to age 6 mo. Between ages 6 mo and 3 y bone mineralization increased in some of the marginal-Zn monkeys to values that were only slightly below those for control monkeys.

MR imaging of the knee: preliminary results with a 3DFT GRASS pulse sequence.

The knees of 17 patients (18 extremities) with possible meniscal, cruciate ligament, and articular cartilage abnormalities were examined with a three-dimensional Fourier transform (3DFT), gradient-refocused acquisition in a steady state (GRASS) pulse sequence. Arthroscopic confirmation was available in all cases and was the standard for comparison. Thirteen of these extremities were also examined by using a two-dimensional Fourier transform spin-echo pulse sequence with a 2000-msec repetition time and 20- and 80-msec echo time. In these 13 cases, both pulse sequences correctly identified seven of eight meniscal abnormalities. However, interpretation of the 3DFT GRASS images resulted in fewer false-positive meniscal tears (three vs six). Cruciate ligament tears were detected more readily on the 3DFT GRASS images (six vs three with two possible tears on the spin-echo images). These preliminary findings suggest that the overall accuracy of MR imaging of the knee could be improved by including 3DFT gradient-refocused pulse sequences.

Pigmented villonodular synovitis: a report of MR imaging in two cases.

Although magnetic resonance (MR) imaging has been used to evaluate many musculoskeletal lesions, the MR appearance of pigmented villonodular synovitis (PVNS) has not been described in detail. The authors describe two cases of PVNS in the knee imaged with both computed tomography and MR. In both cases parts of each lesion had very low signal intensity on both short repetition time (TR)/echo time (TE) sequences and long TR/TE sequences. Other portions of both lesions had intermediate signal intensity (equal to or higher than that of muscle but lower than that of fat) on short TR/TE sequences and increasing signal intensity on longer TR/TE images. In one case, the lesion also had a cystic component that showed MR changes typical of complex fluid. The authors propose that the MR signal characteristics demonstrated in these cases may be explained by the unique tissue components of the lesion, particularly hemosiderin and fat.

CT of the lumbar spine: normal variants and pitfalls.

Benign variants in the appearance of the lumbar spine on CT may be confused with significant lesions. Here such benign processes and their distinguishing features are illustrated.