The effect of surgery and remodelling on spinal canal measurements after thoracolumbar burst fractures.

Bone fragments in the spinal canal after thoracolumbar spine injuries causing spinal canal narrowing is a frequent phenomenon. Efforts to remove such fragments are often considered. The purpose of the present study was to evaluate the effects of surgery on spinal canal dimensions, as well as the subsequent effect of natural remodelling, previously described by other authors. A base material of 157 patients operated consecutively for unstable thoracolumbar spine fractures at Sahlgrenska University Hospital in Gothenburg during the years 1980-1988 were evaluated, with a minimum of 5-years follow-up. Of these, 115 had suffered burst fractures. Usually the Harrington distraction rod system was employed. Patients underwent computed tomography (CT) preoperatively, postoperatively and at follow-up. From digitized CT scans, cross-sectional area (CSA) and mid-sagittal diameter (MSD) of the spinal canal at the level of injury were determined. The results showed that the preoperative CSA of the spinal canal was reduced to 1.4 cm2 or 49% of normal, after injury. Postoperatively it was widened to 2.0 cm2 or 72% of normal. At the time of follow-up, the CSA had improved further, to 2.6 cm2 or 87%. The extent of widening by surgery depended on the extent of initial narrowing, but not on fragment removal. Remodelling was dependent on the amount of bone left after surgery. The study shows that canal enlargement during surgery is caused by indirect effects when the spine is distracted and put into lordosis. Remodelling will occur if there is residual narrowing. Acute intervention into the spinal canal, as well as subsequent surgery because of residual bone, should be avoided.

Radiologic progression of isthmic lumbar spondylolisthesis in young patients.

In 311 patients (160 girls and women and 151 boys and men) with lumbar spondylolysis/spondylolisthesis 30 years of age or younger at diagnosis and with at least two separate examinations available, radiographs were evaluated retrospectively to estimate the magnitude of slip progression in relation to age and to search for possible prognostic factors of progression. The mean age at diagnosis was 16.2 years, and the mean observation time was 3.8 years. Nine patients (3%) had a slip progression (defined as an increase greater than or equal to 20%). The magnitude of progression per year was low (0.6%). No prognostic factors for progression were found.

Fixation of ankle fractures: power-driven staples compared with a routine method, a 3-year follow-up study.

A new method of internal fixation of ankle fractures with power-driven staples is presented. The results in 25 ankle fractures treated with this method were compared with those of 25 matched ankle fractures treated with Wiberg staples, cerclage, and Palmer pins. Reduction was exact in 22 fractures in the stapled group and in 23 in the routine group; all the fractures healed within 6 weeks. The only difference between the two groups was a gain of 20 min in operating time when using the power-driven staples (p less than 0.01). At follow-up observation 3 years later, no additional significant subjective, objective, or radiological differences appeared.

Roentgenologic assessment of spondylolisthesis. II. An evaluation of progression.

Different degrees of artificial L5-S1 spondylolisthesis were created using a lumbar specimen. Lateral radiographs were obtained of each, with the specimen tilted and/or rotated. The true spondylolisthesis was determined stereophotogrammetrically. The slip, measured on the radiographs, was calculated according to two methods modified from Boxall et coll. No significant difference in accuracy was found between these two methods. The difference in calculated slip between examinations needs to be at least 20 per cent of the sagittal length of L5 to be regarded as a true progression. A true progress of slip of less than 20 per cent is difficult to detect with statistical certainty.

Internal fixation of femoral neck fracture. No difference between the Rydell four-flanged nail and Gouffon's pins.

Two methods of internal fixation of femoral neck fractures were compared in a prospective randomized study of 223 patients. Radiographic evidence of early redisplacement, nonunion, or late segmental collapse occurred in 45 of 122 patients operated on with the Rydell four-flanged hook nail and in 33 of 101 patients operated on with Gouffon pins. According to the actuarial method of follow-up, the failure rates after 2 years were respectively 41 and 35 percent in the nail and pin groups, which is a nonsignificant difference.

Intrinsic disc pressure as a measure of integrity of the lumbar spine.

Intradiscal pressure and volume measurements were made in 84 fresh cadaveric lumbar spine disc spaces. The nucleus was injected with a roentgenographic contrast agent under fluoroscopic examination. The intrinsic pressure, the pressure at which the agent entered the disc, and the maximum pressure that the disc could hold were measured. The discs were graded for degeneration. The intrinsic and maximum pressures were found to be inversely related to disc degeneration grade, and directly related to each other. Relatively greater degeneration was found at lower levels of the lumbar spine as compared to the upper levels. The intrinsic disc pressure may prove to be a useful clinical tool in the evaluation of spinal integrity.

Roentgenologic assessment of spondylolisthesis. I. A study of measurement variations.

Variations when measuring slip and lumbar index were studied in three lumbar specimens with different degrees of artificially created L5-S1 spondylolisthesis. Lateral radiographs were obtained with the specimens tilted and/or rotated mimicking an every-day examination situation. Slip and lumbar index were measured; slip was estimated according to a measuring method advocated by BOXALL et coll. (3) but slightly modified by us. Six radiologists evaluated each film independently. The magnitude of interobserver and intraobserver errors and variations due to positioning was found to be equally large--about 15 per cent each. Although the total measurement variation was not equal to the sum of errors involved, radiologic evaluation of degree of spondylolisthesis was found to be highly unreliable.

Radiologic examination and measurement of the wrist and distal radio-ulnar joint. New aspects.

Following fractures of the distal radius, a relatively high incidence of complications is caused by malalignment in the distal radio-ulnar (DRU) joint; recent anatomic and clinical investigations have shown congruity of that joint to be of significant importance for restoring the function of the wrist. The radius forms a moderately arched bone, which moves around the ulna in pronation and supination. Biomechanically, the ulna may be regarded as the pillar around which the radius moves. In an anatomic investigation of 5 arm specimens, we have shown that the maximum cartilage contact in the DRU joint between the ulnar head and the distal radius occurs in the neutral rotation position. A proposed routine examination method of the wrist and forearm includes a true antero-posterior and a lateral projection of the radius and the ulna, performed with the forearm and wrist in a neutral rotation, a neutral wrist deviation and with the elbow angled 90 degrees. Such an examination implies a standardized and reproducible method. In a radioanatomic investigation, a series of 50 healthy wrists and forearms were examined. A simple measuring technique is presented, applicable to the DRU joint and wrist favouring the ulna as the bone through which a reproducible long axis of the forearm/wrist may be drawn. It is suggested that the length of the radius should be judged relative to the ulna. Ulnar head inclination and radio-ulnar angle are new concepts, being major characteristics of the DRU joint. These angles of the right and left wrist were equal and no difference was found between the sexes. Minor alterations of the distal radius may be revealed when estimating these angles.

Metacarpophalangeal joint replacement with osseointegrated endoprostheses.

A new type of endoprosthesis for reconstruction of the metacarpophalangeal (MCP) joint has been tested. The novel arthroplasty consists of a joint mechanism with two screw-shaped fixtures for bone anchorage. These fixtures, of commercially pure titanium, are gently screwed into the anchoring bone on each side of the diseased joint, the aim being to achieve osseointegration, i.e. a direct contact between implant and bone without interposed soft tissue layers. The hand was immobilized in a dorsal splint for 8-10 days post-operatively after which a carefully controlled mobilization program was initiated. In principle, the titanium fixtures, the surgical technique and the primary immobilization represent an approach similar to that previously used in various reconstruction procedures of the jaw. This paper describes 5 case histories of reconstructions required because of osteoarthrosis in a single MCP joint. Prior to the operation, all patients suffered from severe problems resulting from their arthrotic joints and they had not been able to work for several months. After surgery they were evaluated by a clinical assessment program and X-rays were taken at various times of follow-up. As well as visual inspection all radiograms were subjected to densitometry by means of a computer-based image-analysis system in order to provide information on the development of bone density in the bone-to implant interface region. From a functional point of view the treatment with osseointegrated prostheses must be regarded as being successful. All patients were able to go back to their original work and their hands had a satisfactory range of movement and grip strength with no signs of impaired function on longer follow-up time. Clinical problems were one re-operation, one case of implant fracture and one case requiring exchange of the joint mechanism. The computer-assisted evaluation of the radiograms revealed the presence of calcified tissue in many sections where the naked eye was not capable of differentiating any bone. In conclusion, it seems possible to establish osseointegration of MCP-endoprostheses in the arthrotic human joint in complicated cases which were regarded as contraindicated for any other joint arthroplasty.

Vascularization of peripheral neurilemomas: angiographic, computed tomographic, and histologic studies.

The vascularization of peripheral neurilemoma was studied in 17 patients, in eight by angiography and in 16 by computed tomography (CT) using contrast enhancement. Angiographically the degree of vascularity varied from scarcity to abundance of vessels. In two patients, arteries connected to the proximal and distal poles of the tumor could be identified as nutrient arteries of the affected nerve, and in three patients some of the veins draining the tumor followed the course of the nerve. All 16 tumors examined by CT showed lower density than skeletal muscle. They were well delineated and at least partially surrounded by adipose tissue. With contrast enhancement the density increased focally, reflecting the distribution of vessels in the tumors. Histologic examination showed that Antoni-A tissue was rich in small (below 15 micron) and medium-sized vessels, whereas large vessels (above 100 micron) were more frequently seen in Antoni-B tissue. Medium-sized and large vessels often tended to be arranged along the border between Antoni-A and Antoni-B tissues.

Unstable thoracolumbar fractures. A comparative radiologic study of conservative treatment and Harrington instrumentation.

Two comparable groups with unstable thoracolumbar fractures have been studied: one consisting of 23 patients treated conservatively and one consisting of 20 patients treated surgically with Harrington instrumentation. The vertebral injuries have been analysed radiologically at the time of injury as well as after completion of conservative and surgical treatment and at follow-up on average 6 years and 3 months after injury in the conservatively treated group and 2 years and 2 months after injury in the operated group. The vertebral fractures were often solitary at the L1 level with a characteristic radiologic appearance and mainly caused by flexion-rotation injuries. There were indirect signs of associated ligament injuries in most cases. Indirect signs of associated disc injury were found in 77 per cent of the cases, most of them related to the superior disc. The signs of disc injury were accentuated at the two follow-up examinations. In the operated group, the radiologic appearance of the vertebral body normalised after Harrington instrumentation. A preoperative gibbus angle of 19.4 degrees was reduced to 6.8 degrees on average postoperatively. In 13 of the operated cases the rods were removed. Among these patients the gibbus angle increased to 17.6 degrees at the final follow-up examination, compared with 11.9 degrees in the patients who had their rods retained. This difference in gibbus angle was significant. In the conservatively treated group, the initial gibbus angle of 19.5 degrees continuously increased to 27.6 degrees at the follow-up examination. All vertebral fractures had healed at the follow-up examination.

Differential diagnosis of recurrent lumbar disc herniation and postoperative deformation by myelography. An impossible task.

A series of 44 patients with persistent or recurring sciatic pain after myelography and operation for disc herniation were remyelographed and reoperated. Patients with lesions at a new level or at the same level but on the opposite side presented no diagnostic problems. However, in patients with myelographic changes at the same level and on the same side as at the first operation, it was impossible to distinguish disc herniation from postoperative extradural scarring. This was true whatever myelographic sign or combination of signs was chosen.

The thoracolumbar crush fracture. An experimental study on instant axial dynamic loading: the resulting fracture type and its stability.

Seven vertebral preparations of L1, with surrounding discs, facet joints, and ligaments were exposed to an instant axial dynamic force in order to produce a burst or crush fracture. The resulting fractures were similar to fractures observed clinically and showed a comminuted vertebral body with fractured vertebral end-plates, dislocated disc nucleus, bone fragments severely encroaching upon the spinal canal, and facet joint laxity. The flexion-extension range was increased considerably. This implies that this fracture type should be regarded as unstable with a risk of progressive flexion deformity, neurologic deterioration and pain. The fracture could be reduced by an axial distraction force of 400 N simulating the effect of Harrington distraction rods. However, the distraction resulted in an "empty" vertebral body with small areas of spongious bone mixed with fragments of the disc nucleus and fragments of the vertebral end-plate.

Unstable thoracolumbar fractures. A study by CT and conventional roentgenology of the reduction effect of Harrington instrumentation.

Fourteen patients with unstable thoracolumbar fractures were examined with conventional roentgenologic technique and CT before and after operation with Harrington instrumentation. CT was superior in evaluating posterior elements, bone fragments in the spinal canal, and degree of narrowing of the spinal canal. Harrington rods restored the general spinal alignment. However, even after surgery, the midsagittal diameter, as well as the cross-sectional area of the spinal canal were still diminished by 26%. The reduction of the spinal canal improved significantly by early surgical intervention. Open reduction and stabilization with Harrington rods and fusion within three days after injury is recommended.

Postural and time-dependent effects on body height and scoliosis angle in adolescent idiopathic scoliosis.

Changes in body height and scoliosis angle under the influence of gravity were studied in 40 patients with adolescent scoliosis. The average decrease in body height was 1% during a day. There were no significant changes in the mean angles of the scoliosis curves during the day. The patients were grouped according to age, standing and sitting heights, weight and skeletal maturation. A decrease in the scoliosis angles occurred in younger, more skeletally immature and lighter individuals, while an increase occurred in older, more skeletally mature and heavier individuals. The difference between the scoliosis angles measured from standing and supine views was also analyzed. The correction of the scoliosis angle in the supine position was on average 19%. No correlation was found between the change in angle and any of the growth factors studied. There was also no correlation between the change in angle and the degree of curvature.

Effect of radiologic contrast media and local anaesthetics on the blood-brain barrier and on the leptomeninges.

The leptomeninges of cats were exposed to lidocaine, metrizamide and methiodal sodium and compared with control brains exposed to Ringer's solution. As a sign of blood-brain barrier damage, an increased extravasation of albumin into the cerebral cortex was recorded after exposure to methiodal sodium; lidocaine or metrizamide did not produce such damage. Scanning electron microscopy revealed minor cellular reactions in the mesothelial cells of the leptomeninges after application of metrizamide, lidocaine and Ringer's solution. Methiodal sodium produced an extensive cellular damage of the leptomeningeal cells. The importance of testing the leptomeningeal reactions and the reactions of the blood-brain barrier to all liquid media used on the brain surface is emphasized.

Long-term anatomic and functional changes in patients with adolescent idiopathic scoliosis treated by Harrington rod fusion.

One hundred patients from the Gothenburg Scoliosis Data Base were studied. They met the following criteria: (1) adolescent idiopathic scoliosis (2) completion of treatment before age 20, (3) a minimum follow-up of five years thereafter, (4) a minimum age of 22 years at final follow-up, and (5) operation performed by the senior author. Of these, 95 were personally examined. The surgical technique from 1968 to 1973 included a two-stage Harrington distraction, with fusion added at the second operation (52 patients). From 1973 to 1975, 48 patients were treated with a one-stage distraction and fusion after a week of preoperative Cotrel traction. Postoperatively, all patients were treated with a Milwaukee brace. A spinal examination and functional assessment, including a questionnaire and pain drawing, full standing anterior-posterior (AP), and lateral roentgenograms of the spine, was performed by independent observers. Eighty-five subjects without scoliosis served as a control group. The radiographic evaluation showed the usual nearly 50% permanent correction at the follow-up examination averaging nine years postoperatively. Lateral roentgenograms, however, demonstrated in 52% flattened or kyphotic cervical spines producing no significant complaints, non-significant flattening of the thoracic kyphosis, but significant lowering of the lumbar lordosis. Fifteen of the 24 patients with distal hook insertion and fusion including L4 or L5 demonstrated retrolisthesis. All had significant low-back pain. Degenerative facet joint changes and disc space narrowing was noted in 11 patients, again with a distal hook purchase in L4 or L5. Compared to the controls, the operated patients, as a group, revealed no lessened activity or back pain at any location.(ABSTRACT TRUNCATED AT 250 WORDS)

The crush-cleavage fracture. A "new" thoracolumbar unstable fracture.

Among 14 patients with unstable thoracolumbar fractures examined by both conventional radiography and CT, we found seven patients with a "new" common fracture pattern. This fracture pattern consisted of (1) superior disc injury, (2) crush fracture of the upper half of the vertebral body, (3) sagittal fracture (cleavage fracture) of the lower half of the vertebral body, (4) bone fragments in the spinal canal, and (5) laminar fracture. Five of the seven patients had sustained their injuries in vertical falls; all five had primary neurological deficit symptoms. We consider this fracture to be unstable.

Surgery versus chemonucleolysis for herniated lumbar discs. A prospective study with random assignment.

The results of removal of a disc hernia at the L4/L5 level were compared with those obtained by the injection of 4000 IU (2 ml) of chymopapain (Discase) in 29 consecutive patients randomly selected for either treatment. All exhibited severe incapacitating sciatica, and all had a myelogram demonstrating a definite disc hernia. The two groups of patients did not differ significantly with regard to age, sex, or length of history. The total time of general anesthesia was significantly shorter for the injected patients by 20 minutes (p less than 0.01), as was the length of hospitalization, by three days (p less than 0.05). Within five months, eight of the patients receiving chymopapain injections had to be operated on because of unrelieved symptoms. All had definite disc herniae, and in four, a free fragment was found. All patients were seen at the time of dismissal from the hospital and at six and 12 months after operation by an independent observer. Comparisons made at these intervals, following either surgery or chymopapain injection with or without subsequent surgery, did not reveal any significant differences, but the short-term results following either treatment alone significantly (p less than 0.01) favored the surgical approach.

Computed tomography of bone fragments in the spinal canal. An experimental study.

The detectability of bone fragments of differing size and structure, placed epidurally in the spinal canal at different levels from T XI to L II, was studied in three vertebral preparations using three different CT scanners, Philips Tomoscan 310, General Electric 8800 and Siemens Somatom 2. The thickness of the bone fragment was the most decisive factor. Cortical bone fragments could be detected down to a thickness of 0.6 mm and spongy bone fragments down to 1.2 mm. No difference in detectability between the different CT scanners was found.