Esophageal perforation after fracture of the cervical spine: case report and review of the literature

We present a posttraumatic esophageal tear that occurred in a 55-year old patient after a truck accident. He sustained a two-level injury with a type II odontoid fracture and a unilateral fracture of the left superior articular process of C6 with an incomplete quadriplegia at C5. Both lesions were treated nonoperatively. The tear was attributed to the stretching of the esophagus over anterior degenerative spurs at the level of the lesion (C5-C6) during hyperextension. The diagnosis of the esophageal perforation was delayed for 6 days. The treatment consisted of surgical debridement, volume expansion, antibiotic therapy, hyperbaric oxygenation, assisted ventilation, and esophageal exclusion. A complete review of the literature was performed.

[Pediatric spinal injuries]

Spine injuries during growth are rare, but in comparison to adults they are more often associated with neurologic impairment. They also may occur without visible injuries in X-rays. The problems of conventional radiologic diagnostics include before all the differential diagnosis between synchondrosis, apophysis and fracture lines. MRI is indicated in case of neurologic deficits without radiologic abnormalities. In principle the fracture types correspond to those seen in adults. In addition growth specific injuries of the end-plates (growth plates) or ring apophysis may occur. Stable compression fractures are treated conservatively. The spontaneous remodelling capacity for posttraumatic deformities decreases with age: in children below the age of ten years the remodelling capacity for posttraumatic kyphosis is excellent whereas deformities in the frontal plane show no or only incomplete remodelling. Unstable fractures and injuries with associated compression of neural structures should be treated conservatively.

[Atlas fractures]

Fractures of the atlas account for 1-2% of all vertebral fractures. We divide atlas fractures into 5 groups: isolated fractures of the anterior arch of the atlas, isolated fractures of the posterior arch, combined fractures of the anterior and posterior arch (so-called Jefferson fractures), isolated fractures of the lateral mass and fractures of the transverse process. Isolated fractures of the anterior or posterior arch are benign and are treated conservatively with a soft collar until the neck pain has disappeared. Jefferson fractures are divided into stable and unstable fracture depending on the integrity of the transverse ligament. Stable Jefferson fractures are treated conservatively with good outcome while unstable Jefferson fractures are probably best treated operatively with a posterior atlanto-axial or occipito-axial stabilization and fusion. The authors preferred treatment modality is the immediate open reduction of the dislocated lateral masses combined with a stabilization in the reduced position using a transarticular screw fixation C1/C2 according to Magerl. This has the advantage of saving the atlanto-occipital joints and offering an immediate stability which makes immobilization in an halo or Minerva cast superfluous. In late instabilities C1/2 with incongruency of the lateral masses occurring after primary conservative treatment, an occipito-cervical fusion is indicated. Isolated fractures of the lateral masses are very rare and may, if the lateral mass is totally destroyed, be a reason for an occipito-cervical fusion. Fractures of the transverse processes may be the cause for a thrombosis of the vertebral artery. No treatment is necessary for the fracture itself.

Safety and accuracy of transarticular screw fixation C1-C2 using an aiming device. An anatomic study

STUDY DESIGN

In this anatomic study, the safety and accuracy of C1-C2 transarticular screw placement was tested in a normal anatomic situation in cadaver specimens using a specially designed aiming device.

OBJECTIVES

To assess the safety and accuracy of transarticular screw placement using the technique described by Magerl and a specially designed aiming device.

SUMMARY OF BACKGROUND DATA

Transarticular C1-C2 screw fixation has been shown to be biomechanically superior to posterior C1-C2 wiring techniques. Several clinical series have been reported in the literature. However, no previous study assessing the accuracy or safety of this technique has been published. Structures at risk are the vertebral arteries, spinal canal, and the occiput-C1 joint.

METHODS

Five frozen human cadaveric specimens were thawed and instrumented with 10 C1-C2 transarticular screws, according to the technique described by Magerl but using a specially designed aiming device described by the senior author (Jeanneret). After screw placement, the accuracy of screw positioning and the distance of the screws from the spinal canal, vertebral arteries, and atlanto-occipital joint were determined by anatomic dissection and radiographic analysis.

RESULTS

The structure at greatest risk was the atlanto-occipital joint, with one screw found to be damaging the joint. Vertebral artery or spinal canal penetration was not observed in any of the specimens. Screw length averaged 45 mm and, with proper length, the screw tip was found to be located approximately 7.5 mm behind the anterior tubercle of C1 on lateral radiographs.

CONCLUSIONS

This anatomic study demonstrates that C1-C2 transarticular screw fixation can be performed safely in a normal anatomic situation by surgeons who are familiar with the pertinent anatomy. The aiming device allowed safe instrumentation in all patients. In case of an irregular anatomic situation (e.g., congenital abnormalities or trauma), computed tomographic scan with sagittal reconstruction is recommended-in particular, to obtain information about the course of the vertebral artery.

[Chronic back pain]

Low-back pain is a very common disease in Switzerland as elsewhere, with a prevalence of 65%. The pain is usually due to degeneration of the motion segment, but subsides spontaneously in some 95% of cases irrespective of the treatment. Only 5% of patients still have pain after one year; but account for over 80% of the costs due to low-back pain. Some patients can be helped by surgical fusion; however; preoperative identification of the pain source is mandatory. Since there is no consistent correlation between pain and the degree of degeneration of motion segments as seen on plain radiographs, functional radiographs, CT scan or MRI, other diagnostic methods such as facet blocks, discography and external diagnostic fixation must be used. After careful patient selection a fusion operation may be considered. Good results after fusion operations are reported in 60-80% of patients. The operative techniques are described.

[In vivo measurement of 3-dimensional movement of the iliosacral joint]

The purpose of this study was to quantify in vivo the three-dimensional motion patterns of the sacroiliac joint during passive manipulations as the opinions about the extent of motion of this joint are varied. 12 sacroiliac joints of 6 patients with clinically and radiologically normal joints were investigated. All patients were treated with an external fixator for diagnostic purposes of low back pain unrelated of this study. The motion of the sacroiliac joint was measured continuously with a three-dimensional goniometric system, which was mounted at the end of Schanz screws implanted in S1 and the ilium. All measurements showed relatively small rotation angles around the three main axis to the body between the ilium and the sacrum (< 2 degrees) and very small translations between the screw entry points into the bones (< 1 mm). The maximum rotation angle in the sagittal plane was 1.3 degrees on the right joint and 1.6 degrees on the left joint for flexion plus extension. It is questionable whether this motion can be quantified during manual manipulation. Extension of the hip always produced the largest motion in the sacroiliac joint.

[Degenerative spinal canal stenosis in lumbar spine: clinical view and treatment.]

Radicular leg pain, combined with numbness and intermittent radicular paresis while walking or standing are typical symptoms of a narrow spinal canal of the lumbar spine. Medical history and lumbar myelogram are usually sufficient to localize the source of pain. We prefer the myelogram to CT-scan or MRI because it gives a longitudinal view of the whole lumbar spine, is easy to read and is also possible in the presence of a scoliotic deformity or claustrophobia. Between 1987 and 1993, 76 patients with symptomatic lumbar spinal stenosis were treated operatively by the same surgeon. Results are available for 74 patients. In all patiens, a decompression was performed, a fusion was performed in 64 patients. The follow-up ranges from 1 to 5.7 years (average 2.7 years). 59 patients (80 %) were happy with the result and would like to be operated again in the same conditions. 8 of the 15 unhappy patients had, objectively, a good result but were unsatisfied for other reasons. Our results show, that operative treatment of the lumbar spinal stenosis is a rewarding task. Decompression usually results in a dramatic decrease of the leg pain and improvement of the walking distance. Advanced age in not a contraindication for this kind of surgery. Decompression combined with fusion results in a longer operative time and greater blood loss and is only indicated in the presence of an instability in a younger patient or massive preoperative back pain. Key words: spinal stenosis, claudication, lumbar spine, decompression, fusion.

The value of percutaneous transpedicular vertebral bone biopsies for histologic examination. Results of an experimental histopathologic study comparing two biopsy needles

STUDY DESIGN

A 3.5-mm trephine was designed to overcome difficulties encountered in the histologic evaluation of vertebral bone samples obtained with a 2-mm trephine.

OBJECTIVES

To compare the 3.5-mm trephine with the 2-mm trephine.

SUMMARY OF BACKGROUND DATA

A review of results obtained with a 2-mm trephine showed that histologic examination of vertebral bone cores was disturbed by artifacts in 32 of 70 cases (46%). Although tissue diagnosis was possible from 61 samples, only 36 (51%) bone cores yielded a secure diagnosis.

METHODS

Transpedicular bone cores were obtained from the bodies of 54 fresh cadaver vertebrae with both trephines. In each vertebra, the 2-mm trephine was used on one side, and the 3.5-mm trephine was used on the other side. Longitudinal sections were prepared and examined macroscopically for length and breakages and microscopically for trabeculae, marrow, and artifacts. Each sample was graded for its value for histologic examination.

RESULTS

Significant differences were found between the two trephines for all criteria evaluated. Of 54 samples taken with the 2-mm trephine, 13 (24%) were graded "good," compared with 45 (83%) from the 3.5-mm trephine. Twelve (22%) "bad" samples were taken from the 2-mm trephine compared with three (6%) "bad" samples taken from the 3.5-mm trephine.

CONCLUSIONS

The 2-mm trephine does not provide suitable bone cores for histologic examination, whereas samples obtained with the 3.5-mm trephine are suitable.

Posterior rod system of the cervical spine: a new implant allowing optimal screw insertion

A new implant system for posterior stabilisation of the occipitocervical junction and the cervical and upper thoracic spine is described. The system consists of rods and clamps. For fixation to the occiput, the 3.5-mm titanium rod goes over into a 3.5-mm AO-reconstruction plate. Several clamps may be fixed to the rod at variable intervals, depending on the anatomical situation and the specific needs. Five types of clamps with different angulations of the screw hole with respect to the rod allow optimal screw insertion and fixation of the rod at all levels instrumented. Locking screws may be used to allow fixed stabilisation of the screw to the rod. Hooks for sublaminar anchoring, connectors to other rods and a cross-linking device are also available. Unlike plate fixators, the system allows screw insertion at any angle and at any interval. Therefore, optimal screw insertion is possible in any anatomical situation. Furthermore, ample space is available for bone grafting of the posterior aspect of the lateral masses. This is especially important following a laminectomy. Preliminary clinical results in 20 patients are presented; no complications have been seen to date. Our system has recently been approved as an AO-implant.

Posterior stabilization in L5-S1 isthmic spondylolisthesis with paralaminar screw fixation: anatomical and clinical results

Combined anterior and posterior fusion with posterior instrumentation may be indicated in the treatment of select cases of L5-S1 spondylolisthesis. The instrumentation, however, is expensive and usually bulky, occasionally requiring removal. In an effort to avoid these problems, an L5-S1 paralaminar screw technique was developed for posterior stabilization after an L5-S1 anterior interbody fusion. The technique involves the placement of cortical screws from the base of the articular process of S1 to the pedicle of L5. This study evaluates the anatomic applications and clinical results of this technique. The relationship between the screw and L5 nerve root was examined using five cadaveric specimens with olisthesis of 0, 25, 50, and 75%. This work demonstrates that the screws can only be inserted safely if an L5-S1 olisthesis of at least 25% is present. If < 25%, the screws will either impinge on or directly injure the L5 nerve root. In the clinical study, the outcomes of 20 patients who had an isthmic spondylolisthesis of 25-81% and were treated with partial reduction, L5-S1 anterior interbody fusion, and L5-S1 posterior paralaminar screw fixation were reviewed. Nineteen patients had adequate posterior stabilization to completely heal an L5-S1 anterior interbody fusion without loss of the correction. In one patient, a pseudarthrosis occurred secondary to poor surgical technique of both anterior and posterior fusions. This patient required an additional L4-S1 posterior fusion 9 months later and had a good clinical outcome. No other complications due to screw placement occurred. We conclude that this procedure can be used safely and reliably for the posterior stabilization of L5-S1 after stable anterior L5-S1 interbody fusion in residual slips of at least 25%. Prerequisites are proper patient compliance and low weight. Compared with other posterior instrumentation systems, this screw fixation is inexpensive and does not require implant removal. The disadvantages of the method are the degree of difficulty of the procedure and the limited clinical application to cases of L5-S1 spondylolisthesis with corrected residual slips of 25 to 50-60%. The procedure is technically demanding and should be limited to those surgeons who are comfortable with the method.

Occipitocervical fusion with posterior plate and screw instrumentation. A long-term follow-up study

STUDY DESIGN

Thirty-two patients at one institution underwent occipitocervical fusions with posterior plate and screw instrumentation. The average follow-up was greater than 4 years (50 months).

METHODS

AO plates and screws were used and in more than 50% of the cases, the Magerl transarticular C1-C2 screw technique enhanced the occipitocervical instrumentation. In nine patients, cement was used and thus are excluded in evaluation of fusion results. All 23 patients attained solid fusions. No pseudarthrosis occurred. The average time to fusion was 13 weeks. Halos or traction immobilization was not used postoperatively. The average time of the simple orthosis wear was 11 weeks. Patients were out of bed on an average of the second postoperative day with a range of 1-4 days postoperatively. Reduction of the atlantoaxial joint was required in 10 of the 23 patients. At follow-up, nine remain reduced.

RESULTS

In one patient, the atlantodens interval approximated the preoperative distance and radiographs demonstrated one transarticular C1-C2 screw was not placed satisfactorily. The average operative time was 172 minutes, and the average blood loss was 956 cc. The neurologic status of the patients improved or remained the same. No patient deteriorated neurologically. A total of 78 occipital screws were placed. No complications resulted from any of these screws. One intraoperative complication occurred secondary to massive bleeding after a transarticular screw hole was drilled. Bone wax was placed over the drill hole and the bleeding ceased. No postoperative problems occurred in this patient. Most specifically, no central nervous system sequela was evident.

CONCLUSIONS

The conclusions from this study are that posterior occipitocervical fusion can be performed very safely with plate and screw instrumentation. An extremely high fusion rate can be expected with minimal complications and minimal postoperative immobilization. This technique, however, is technically demanding.

Percutaneous diagnostic stabilization for low back pain. Correlation with results after fusion operations

Diagnostic external fixation was performed in 101 patients with disabling low back pain. In 47 patients, pain was relieved by stabilization but returned after destabilization. These patients were considered good candidates for a fusion operation. Results after fusion are available for 34 patients: 14 (41%) patients had a good, 12 (35%) had a fair, and 8 (14%) had a bad result. In two patients, pain was relieved by stabilization and did not return after fixator removal; no fusion operation was performed. Fifty-two patients did not respond positively to external fixation. Nine were operated on despite negative results with fixation. Of these, seven patients had a bad result, one a good result (however, this patient had spinal stenosis and the indication for external fixation was wrong), and, in one, the follow-up time is too short. Positive results with external skeletal fixation may predict a successful fusion operation with reasonable accuracy. If stabilization does not relieve the patient's pain, spinal fusion is unlikely to be of any benefit.

Transpedicular screw fixation of articular mass fracture-separation: results of an anatomical study and operative technique

Articular mass fracture-separation accounts for 9% of the fractures of the lower cervical spine. Neurologic complications are frequent and are usually radicular in nature. Unreduced, these fractures may cause persistent neck pain. The treatment is usually surgical, fusing two or three vertebrae. In this article we present a new treatment modality using reduction and stabilization of the dislocated fragment with a transpedicular lag screw. Previous anatomic studies have shown that the pedicles of the lower cervical spine are wide enough to accept 4.0-mm screws. An anatomic study was performed showing that transpedicular screw fixation is safe when the following technique is used: entry point 3 mm beneath the facet joint on a vertical line in the middle of the articular mass. The drill is angled medially, depending on the preoperative measurement on the computed tomography scan (average 45 degrees). The drill aims toward the cranial third of the vertebral body as seen on lateral fluoroscopy. The tap-drilling method is used. After placement of 33 screws in cadaver pedicles of the cervical spine, 10 had minor breakout of the cortex of the pedicle (only small parts of the threads were penetrating the cortex); none showed major violation of the pedicle wall. The most common direction of minor pedicle violation was lateral. Transpedicular screw fixation has been successfully used in three patients.

Treatment of osteomyelitis of the spine using percutaneous suction/irrigation and percutaneous external spinal fixation

External skeletal fixation is a well-known tool in the management of infection of long bones. However, the application of external skeletal fixation in the treatment of spinal infection has not been previously reported. We have used percutaneous external spinal fixation (PESF) for the treatment of osteomyelitis of the spine in 23 patients since 1981. The treatment consists of percutaneous vertebral biopsy for bacteriologic diagnosis, installation of a suction/irrigation system into the intervertebral disk space, and posterior stabilization (and reduction if indicated) with an external fixator placed percutaneously. This treatment was conceived in 15 patients as definitive treatment. One patient died due to pulmonary embolism. In 12 patients, the infection healed without further operative treatment. Preoperative kyphosis averaged 15 degrees (range 0-30 degrees). At follow-up, kyphotic deformity also averaged 15 degrees (range 0-30 degrees). Two patients required anterior debridement and bone grafting because of progression of bony destruction. In eight patients, PESF was performed emergently, followed by planned anterior debridement and interbody grafting. The treatment was successful in all patients. All fusions healed. Preoperative kyphosis averaged 18 degrees (range 0-40 degrees). At follow-up, kyphotic deformity averaged 10 degrees (range 0-22 degrees). Our present indications are listed below and comprise pyogenic and tuberculous osteomyelitis of the spine localized between T3 and S1. The procedure is an alternative to conservative or more invasive operative treatment modalities in the following conditions: (a) painful lesions of the spine with minimal bone loss, not amenable to efficient orthotic stabilization (thoracic spine from T3 to T9, lumbosacral junction, elderly patients, or presence of deleterious general conditions); (b) osteomyelitis of the spine from T3 to S1, when emergency decompression of the spine is mandatory because of neurologic deterioration due to the kyphotic deformity or to a noncapsulated epidural abscess and anterior decompression is not possible emergently; (c) pyogenic osteomyelitis of the spine at L5/S1, when operative treatment is indicated. In addition, percutaneous insertion of external skeletal fixation is indicated in the presence of infected wounds, making internal posterior stabilization unsuitable (e.g., after open decompression of epidural abscess, postoperative infections).

The problem of stabilization after sacrectomy

After sacrectomy, mobilization of the patient is only possible if a stable connection between the spine and pelvis can be obtained. We have developed an instrumentation to fix the pelvis to the spine. Two DHS screws connected to each other were implanted in the pelvis (one DHS screw into each ilium). An internal spine fixator, anchored in L3 and L4 through transpedicular Schanz screws, was attached to these DHS screws. Two patients were stabilized with this implant after sacrectomy. One patient was able to walk with crutches; the other patient was able to walk even without crutches.

Burst-shear flexion-distraction injuries of the lumbar spine

Seven cases of a previously undescribed lesion of the lumbar spine consisting of a burst fracture of the vertebral body associated with a posterior subluxation of the adjacent lower level facet joints are described. The lesion is due to a flexion-distraction mechanism. All seven cases reported involve a burst fracture (four upper burst, one burst-split, and two complete burst fractures). The dislocation line goes through the upper end-plate, through the posterior wall of the fractured vertebra, through the spinal canal, and through the caudal facet joints. The caudal disk is not destroyed primarily, but is involved in cases of burst-split or complete burst fractures. The treatment is surgical: reduction of the posterior subluxation, reduction of the burst fracture with anterior distraction (e.g., AO internal fixator or any other pedicle system allowing anterior distraction and reduction of the burst fracture), transpedicular bone grafting of the burst fracture if necessary, and fusion of the destroyed motion segment(s).

[Anamnesis and myelography in the preoperative assessment of lumbar spinal stenosis. Results of a postoperative follow-up study]

Between 1987 and 1991, 33 patients with spinal stenosis of the lumbar spine were treated by decompression (33 patients) and posterior fusion (30 patients). Indication for decompression was based on case history and lumbar myelography with flexion/extension views. At follow-up 1-5.5 years later, 28 patients were happy with the results of the treatment and would be willing to be operated on again in a similar situation. Two other patients also presented objectively good results, but were dissatisfied for reasons not related to the operation. Our study shows that myelography and case history are adequate investigations for determination of the level of pathology and for making a decision about operative decompression in spinal stenosis of the lumbar spine. CT or MRI are only needed if the symptoms of the patient are not explained by the myelogram. Although MRI is advocated as the investigation of first choice for lumbar spinal stenosis, we still prefer the myelography, which is easier to interpret during the operation. Our study also shows that operative treatment of spinal stenosis is very rewarding, since 9 out of 10 patients will have good results. We usually combine decompression and fusion. Decompression alone is only performed in patients without any back pain and with stable motion segments after adequate decompression.

[Vertebral fractures and abdominal trauma. A retrospective study based on 415 documented vertebral fractures]

415 spinal fractures were analysed retrospectively. A simultaneous occurrence of vertebral fracture and abdominal trauma was found in 14 patients (3.4%). The mechanism of injury was a fall from a considerable height in 9 cases, a car accident in 3 and a motorcycle accident in 2. Isolated fractures of the transverse processes and rotational injuries of the spine were found to be associated particularly frequently with an abdominal trauma (3 of 14 isolated fractures of the transverse processes = 22%, 5 of 61 rotational injuries = 8.2%), while compression injuries only showed such a simultaneous abdominal injury in 2% of the 300 fractures of this type. We never encountered the combination of distraction injury/abdominal trauma. This is probably because two-point lap-type seat belts are only rarely used in our country. In 2 patients with rotational injuries neurological deficits were observed. The abdominal injuries encountered in our patients were: massive concussion of the kidney (6 cases), rupture of the spleen (3 cases), rupture of the liver (2 cases), rupture of the mesocolon (2 cases), rupture of the caecum (1 case), rupture of a pre-existent aneurysm of the aorta (1 case), rupture of a renal artery (1 case), massive retroperitoneal haematoma (1 case). Other injuries were present in 12 of the 14 patients: 3 craniocerebral injuries, 7 fractures of the long bones, 6 injuries to the thorax and 3 to the pelvis. In conclusion, a simultaneous finding of vertebral fracture and abdominal trauma is rare in our patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary posterior fusion C1/2 in odontoid fractures: indications, technique, and results of transarticular screw fixation

Odontoid fractures, especially unstable type II fractures have a poor prognosis in respect to healing. Therefore, operative stabilization (posterior fusion C1/2 or anterior screw fixation) has been suggested for the treatment of unstable type II and for some unstable type III fractures. Compared to posterior fusion C1/2, anterior screw fixation has proven to be effective; it has the advantage of leaving the motion segment C1/2 intact, therefore preserving at least some C1/2 rotation. However, in some instances, this method of stabilization is not indicated. In these cases, posterior fusion C1/2 is the treatment of choice. Primary posterior fusion C1/2 is indicated in (a) odontoid fracture associated with comminution of one or both atlanto-axial joints; (b) fracture of the odontoid associated with an unstable Jefferson fracture; (c) unstable type III odontoid fracture, when immobilization in a halo jacket or plaster cast is not suitable, as in elderly people or polytraumatized patients; (d) atypical type II fractures (comminuted or with oblique fracture in the frontal plane); (e) irreducible fracture dislocation C1/2, e.g., several-weeks-old fracture; (f) unstable type II or shallow and unstable type III odontoid fracture, when marked thoracic kyphosis is associated with limited extension of the cervical spine; (g) unstable type II or shallow type III odontoid fracture in elderly people with degenerative narrow spinal canal; (h) pathologic fracture of the odontoid. In all these instances, posterior fusion C1/2 is the treatment of choice. We prefer the transarticular screw fixation technique. Compared to other posterior fusion techniques, it has the advantage of increased stability and allows effective stabilization of C1/2 in a reduced position as well as immediate ambulation with minimal head support. This technique can also be performed when the posterior arch of the atlas is fractured or absent. Our experience of 12 acute odontoid fractures, managed by this technique, is presented. At follow-up, all C1/2 fusions were united in reduced position.

Atlanto-axial fusion with transarticular screw fixation

We reviewed 161 patients, from four centres in Switzerland, who had undergone posterior fusion of the upper cervical spine with transarticular screw fixation of the atlanto-axial joints. They were followed up for a mean 24.6 months. The vertebral artery and the medulla escaped injury and only 5.9% of the complications were directly related to the screws. The rate of pseudarthrosis was 0.6%.

Atlantoaxial mobility after screw fixation of the odontoid: a computed tomographic study

Between 1979 and 1989, anterior screw fixation of the odontoid process was performed in 16 patients with fractures of the odontoid. One patient died suddenly 2 days after the operation. Postmortem examination could not disclose the cause of death. No other complication was noted. We followed 13 patients. At examinations 7 to 82 months after injury, all fractures were consolidated in reduced position. In all patients, a functional computed tomographic (CT) examination of the atlantoaxial rotation was performed. Atlantoaxial rotation measurement ranged from 7 to 38 degrees to the right (average: 25.2 degrees) and 7 to 41 degrees (average: 24.1 degrees) to the left side. Five patients presented a normal range of atlantoaxial rotation, 29 to 41 degrees; 3 had a rotation of 20 to 28 degrees; 3 a rotation of 10 to 20 degrees; and in 2, rotation was less than 10 degrees to one side. Our results suggest that anterior screw fixation is the therapy of choice for Type II and cephalad Type III dens fractures. However, significant complications have been reported by other authors. Therefore, a careful surgical technique is mandatory, and contraindications should be respected.

Posterior stabilization of the cervical spine with hook plates

Hook-plate fixation is designed for posterior cervical stabilization from C2 to C7. Indications remain the same as for standard posterior fixations. The prime indications are discoligamentous injuries. The plates are hooked under the lower laminas and attached to the articular masses of the upper vertebra by oblique screws. An H-graft is placed between the spinous processes. The vertebrae are compressed together by the plates at three points, the facet joints, and graft. The resulting pre-stressed system is stable in all directions. A protocol for safe reduction of cervical dislocations is observed. Of 70 patients treated from 1979 to 1986, 51 were examined 12-54 months after surgery. All fusions consolidated. Two neurologic complications not attributable to the fixation occurred. Other major complications were not seen.

Overdistraction: a hazard of skull traction in the management of acute injuries of the cervical spine

In acute cervical spine trauma, skull traction is used to reduce a dislocation or fracture dislocation, to immobilize an unstable lesion until definitive treatment (operative or conservative) is possible or, more rarely, as a definitive treatment until healing occurs. This method may be dangerous when an unstable lesion is accidentally overdistracted. A few cases have been reported in the literature, some with neurological complications. We report five cases in which overdistraction was seen. Two hangman's fractures were overdistracted. One of the two patients developed a Cheyne-Stokes breathing pattern during traction which resolved after the weight was reduced. Furthermore, two hyperextension/distraction injuries (C4/5 and C6/7) and one bilateral C5/6 fracture dislocation were overdistracted without neurological deterioration. Occipitocervical dislocations, fractures of the odontoid process, hangman's fractures, hyperextension/distraction injuries and bilateral dislocations or fracture dislocations may present disruption of both the anterior and posterior elements. Therefore, these injuries are specially vulnerable to overdistraction when skull traction is used. To prevent accidental overdistraction during skull traction, we recommend the use of less weight than is generally proposed in the literature. To reduce a dislocation, we start traction weight at 2 kg and slowly increase it under continuous neurological and radiological monitoring until reduction is completed. Traction of 5-7 kg is usually sufficient; however, heavier traction may occasionally be necessary. After reduction is completed, traction is reduced to 2 kg. This weight is sufficient to immobilize a lesion until definitive treatment is possible. Inadvertent rotation may be prevented by placing sandbags on both sides of the head.

Congenital fusion C0-C2 associated with spondylolysis of C2

This is the report of a very rare malformation at the cranio-cervical junction, including congenital occipito-cervical fusion C0-C2, spondylolysis of C2, and hypoplasia of the right vertebral artery. The malformation itself is part of a Klippel-Feil syndrome with sensory-neural hearing loss on the left side, congenital high thoracic scoliosis, rib agenesis on the right side, and kidney malformations on both sides.

[Snapping palmar drawer phenomenon of the wrist: a physiologic or pathologic study finding?]

In the examination of a wrist, when this is held in neutral position and moderate ulnar deviation, a substantial palmar drawer translation combined with a snap can be elicited. The sign is most evident in about 15 degrees of ulnar deviation, while it is negative in the neutral position, in radial deviation or in maximal ulnar deviation. The translation and the snap have been consistently demonstrated in normal wrists and are therefore considered physiologic. The knowledge of this impressive phenomenon seems important for differential diagnosis when assessing the stability of a wrist; its clinical and cineradiographic picture are described.

[Infectious spondylitis]

Nowadays, early diagnosis of spondylitis is possible. Technetium and gallium scintigrams are positive soon after the onset of the disease, while radiographs remain negative for weeks or even months. Blood and urine cultures and serologic tests may provide indications about the underlying infectious agent; however, needle biopsy establishes a precise bacteriologic diagnosis in up to 65% of the cases. Therefore, needle-biopsy is considered to be the most valuable diagnostic measure in spondylitis. Conservative treatment is indicated in cases of minimal destruction of the vertebral body. Surgery may be considered in cases of massive bone loss and kyphosis, and is strictly indicated in cases with spinal instability, abscess formation, and neurologic or septic complications, and when conservative treatment is ineffective.

[Simultaneous rotation and lateral inclination of the head. A clinical sign of restricted motion in segment C1/2]

The clinical diagnosis of a restricted motion at the atlanto-axial level is not always easy. Especially in the presence of a painful restricted neck motion, our clinical tests are unreliable. During a clinical controlled study of patients with dorsal fusions C1-2, we noted a constant and very obvious combined motion of the head: The rotation of the head was not only markedly limited, but it was constantly associated with an ipsilateral tilt of the head. This combined motion of the head can be used as a diagnostic sign of a restricted motion at the atlanto-axial level. Clinical pictures and pathomechanism of this phenomenon are explained.