Acrylic fixation of atlanto-axial dislocations. Technical note

Cervical spine surgery: an historical perspective

BACKGROUND

Continued innovation in surgery requires a knowledge and understanding of historical advances with a recognition of successes and failures.

QUESTIONS/PURPOSES

To identify these successes and failures, we selectively reviewed historical literature on cervical spine surgery with respect to the development of (1) surgical approaches, (2) management of degenerative disc disease, and (3) methods to treat segmental instability.

METHODS

We performed a nonsystematic review using the keywords "cervical spine surgery" and "history" and "instrumentation" and "fusion" in combination with "anterior approach" and "posterior approach," with no limit regarding the year of publication. Used databases were PubMed and Google Scholar. In addition, the search was extended by screening the reference list of all articles.

RESULTS

Innovative surgical approaches allowed direct access to symptomatic areas of the cervical spine. Over the years, we observed a trend from posterior to anterior surgical techniques. Management of the degenerative spine has evolved from decompressive surgery alone to the direct removal of the cause of neural impingement. Internal fixation of actual or potential spinal instability and the associated instrumentation have continuously evolved to allow more reliable fusion. More recently, surgeons have developed the basis for nonfusion surgical techniques and implants.

CONCLUSIONS

The most important advances appear to be (1) recognition of the need to directly address the causes of symptoms, (2) proper decompression of neural structures, and (3) more reliable fusion of unstable symptomatic segments.

Atlantooccipital transarticular screw fixation for the treatment of traumatic occipitoatlantal dislocation

✓ The authors describe a new technique of internal atlantooccipital screw fixation involving posterior wiring and fusion for the treatment of traumatic atlantooccipital dislocation, which was performed in a 17-year-old male patient involved in a motor vehicle accident and who suffered from atlantooccipital dislocation without neurological injury. At the 6-month follow-up examination, the patient was neurologically intact with a solid occipitocervical fusion and full range of motion of the neck.

Arteriovenous fistula as a complication of C1-2 transarticular screw fixation. Case report and review of the literature

A case is reported of a vertebral artery-to-epidural venous plexus fistula as a complication of posterior atlantoaxial facet screw fixation. The use of transarticular screws to stabilize the C1-2 joint has become an increasingly popular fixation technique, most notably for atlantoaxial instability due to trauma or rheumatoid disease. Despite the fact that this approach is technically challenging, there have been few reports of complications associated with C1-2 transarticular fixation. Although damage to the vertebral artery is a documented hazard of transarticular fixation at this level, a symptomatic arteriovenous fistula resulting from the procedure has not been described previously. The etiology, presentation, and treatment of this unusual complication are discussed.

Surgical management of atlantoaxial nonunions

Sixteen patients referred for atlantoaxial fixation failures were treated surgically with revision procedures during the past decade. Of these 16 patients, atlantoaxial instability occurred because of rheumatoid arthritis in five, as odontoideum in seven, transverse ligament disruption in two, and odontoid fracture nonunion in two. The 16 individuals (10 men, six women; mean age 43.7 years; age range 20-77 years) had undergone a total of 20 C1-2 internal fixation procedures that failed. Surgical strategies for definitive revision of the nonunions in these 16 subjects included 10 rigid internal fixations with transarticular screws, three revised C1-2 fixations with autogenous bone struts and wire or cables, and three extended fixations with occipitocervical instrumentation. Autogenous grafts were used in all revisions. A postoperative halo brace was used in five individuals with osteoporotic bone; all patients wore a restrictive postoperative cervical orthosis. Postoperatively, 15 patients (94%) had a stable construct (mean follow up 35 months; range 12-79 months), which included 13 osseous unions and two stable fibrous unions. One patient had nonunion; he fractured his anterior C1-2 transarticular screws 2 years postoperatively. He had occipital radicular pain without myelopathy but refused further surgery. Atlantoaxial pseudarthroses were effectively treated by addressing the pathological, biomechanical, and technical reasons for failed fusion. Successful fusion after reoperation was improved by using autologous bone grafts, adequately controlling atlantoaxial motion (with rigid transarticular screws internally or externally with a halo vest), compressing the bone grafts between the arches of C-1 and C-2 with wire cables, meticulously preparing the fusion bed, and by optimizing the pharmacological and clinical parameters to promote bone healing.

Plate and screw fixation for atlanto-axial subluxation

Our experience with 30 cases of atlanto-axial dislocation, over the period of 3 years and 9 months, is described. A modified plate and screw method of fixation of the lateral masses of the atlas and axis was successfully used in these cases. The technical aspects and merits of the method, wherein a 100% union rate was achieved, with no morbidity, mortality, or instrument fatigue or failure, are presented. The average follow-up period is of 19 months. The technique provided immediate rigid segmental internal fixation, permitting early mobilization with minimal external support. Onlay and interfacetal bone grafts subsequently produced bony fusion. Direct application of screws to the atlas and axis, thus utilizing the firm purchase in their thick and large cortico-cancellous lateral mass, provides a biomechanically strong fixation of the region. Occipito-cervical fusion can be achieved in selected cases by a modification of the method. It appears that such a method of fixation could be useful at least in some complex congenital or traumatic craniovertebral region instability where the conventional methods have failed or are not suitable.

The acrylic-wire option in cervical spine fixation. A retrospective study

This retrospective study was undertaken to assess the stability of the cervical spine after fixation with acrylic wire implants. Of the 44 patients with various pathological conditions of the cervical spine selected for this treatment in the course of 20 years, 36 were considered suitable for long-term follow-up evaluation. In 30 cases (83%) the stability of the spine was rated good. It is concluded that the acrylic-wire combination is a valuable surgical option in certain conditions i.e. old age, short life expectancy, poor general health, mental disease, in which long confinement in bed or in orthopaedic appliances is poorly tolerated.

Surgical stabilization of cervical spinal fractures using methyl methacrylate. Technical considerations and long-term results in 52 patients

This study analyzes the long-term outcome of 52 consecutively treated patients with acute cervical spinal fracture/dislocation who underwent posterior surgical stabilization using methyl methacrylate in the absence of bone grafting. The patients ranged in age from 15 to 93 years. In 40 patients the injury was located in the lower cervical spine; for these a previously described surgical format was employed. In 12 patients the fracture involved C-1 or C-2, and the modification used for these injuries is presented. The postoperative period of evaluation ranged from 6 months to 12 years. There was one case of infection, which eventually required removal of the acrylic, but there were no instances of new neurological injury or of operative mortality. Failure of stabilization occurred in two previously reported patients treated early in the series. Comparison of the patient outcome in this study with that of certain other reports suggests that at least four technical factors are important for the success of methyl methacrylate stabilization: 1) the acrylic inlay must be provided with an anchor to bone; 2) the anchor must be of a type that does not easily erode through bone; 3) the inclusion of wire must be done in a manner that allows each strand to be completely encased in the acrylic; and 4) the cross-sectional area of the inlay is critical.

Evaluation and treatment of atlas burst fractures (Jefferson fractures)

Although several large series of atlas fractures have been reported recently, none has concentrated on the evaluation and treatment of atlas burst fractures (Jefferson fractures). The treatment of this fracture is challenging. Its diagnosis may easily be missed due to concerns about associated trauma and absence of neurological signs. In addition, the open-mouth anteroposterior x-ray study, which is usually pathognomonic for the diagnosis, is often inadequate or not obtained. In order to clarify the diagnosis and treatment of this disorder, 17 cases of Jefferson fracture treated between 1982 and 1989 at the Louisiana State University Affiliated Hospitals are presented. The diagnosis was delayed in three patients because of a low index of suspicion and inadequate x-ray films. Four patients were noted to have unstable Jefferson fractures, all of these had an associated Type II odontoid fracture and were treated with occiput-C-2 wiring and fusion. The remainder of the patients had stable Jefferson fractures and were managed with Minerva jackets or rigid collar stabilization. No significant complications related to the treatment of the Jefferson fracture occurred in this series. One patient died from associated injuries; however, the remaining patients enjoyed an excellent long-term result with the acquisition of spinal stability and the resolution of subjective complaints.

Surgical treatment of extradural spinal cord compression due to metastatic tumours

The authors present a group of 23 patients with extradural spinal metastases who had undergone surgical treatment with different approaches, with reference to the anatomical site of the tumours. They report the results and discuss the criteria of the different surgical technical choices.

The interspinous method of posterior atlantoaxial arthrodesis

Thirty-six patients underwent C1-2 posterior wiring and fusion procedures over a 5-year period for unstable C-2 fractures (eight cases), unstable atlas-axis combination fractures (six cases), rheumatoid C1-2 instability (14 cases), os odontoideum (four cases), traumatic C1-2 ligamentous instability (three cases), or instability secondary to a C-2 tumor (one case). In each case, the atlantoaxial arthrodesis utilized sublaminar wire at C-1 and incorporated an iliac-crest strut-graft positioned between the posterior arches of C-1 and C-2, held in place by securing wire around the base of the spinous process of the axis. Follow-up examination was performed in all patients after a mean postoperative duration of 33.7 months. The technical aspects and clinical merits of this fusion procedure, which led to a 97% union rate (one nonunion) and minimal morbidity and mortality rates, are presented.

Stabilization of the unstable upper cervical spine in rheumatoid arthritis

We present our clinical experience and the results of surgical treatment of 13 patients with rheumatoid involvement of the cervical spine, namely severe atlanto-axial dislocation. A posterior fusion was carried out using a bicortical H-shaped iliac crest bone graft and steel wire. Postoperatively all patients were immobilized for 8 weeks in a Halo cast. There were no postoperative complications and all patients showed a stable fusion confirmed by radiography. Complete pain relief was obtained in 9 patients, partial in 4.

The use of cement forms to control methylmethacrylate in immediate posterior stabilization of the cervical spine. A technical note

Under certain clinical conditions, posterior stabilization of the cervical spine, supplemented with polymethylmethacrylate (PMMA), is an accepted method of achieving stability. A technique is described in which "cement forms" are used to limit the spread of PMMA and to allow bone graft placement in the lateral paraspinous gutters.

Posterior cervical reconstruction with methyl methacrylate cement and wire: a clinical review

The charts and radiographs of 20 patients who were treated for traumatic cervical instability by the Department of Neurosurgery at the University of Virginia by means of posterior reconstruction with methyl methacrylate cement and fixation wires were reviewed by the Department of Orthopaedic Surgery. Based primarily on radiographic criteria, it was found that posterior reconstruction failed to rigidly immobilize the underlying unstable motion segments in 11 patients. Four of these patients required additional surgery to correct postoperative instability. Based on this experience, cement and wire reconstructions are now recommended only when: 1) they can be limited to one cervical level; 2) No. 18 fixation wire is used; 3) wiring is performed from a facet on one side to the adjacent spinous processes; and 4) autogenous bone graft is added to the posterior elements on the side of the midline opposite the cement and wire.

Atlanto-axial dislocation in rheumatoid arthritis--diagnostic and therapeutic aspects

Symptoms, signs and neuroradiological findings of 15 cases with atlanto-axial dislocation (AAD) due to rheumatoid arthritis are presented. CT of the craniocervical region revealed the exact anatomical relationships between the dens, the subarachnoid space and the brain stem, especially after intrathecal contrast medium injection and different positions of the head. From the results of operative procedures to reduce AAD it was concluded that early diagnosis and treatment of AAD leads to prompt relief of painful symptoms within 3 months and protects from neurological deterioration.

Traumatic atlanto-occipital dislocation. Case report

Traumatic atlanto-occipital dislocation is a serious injury that is usually fatal. The number of patients surviving this injury, however, appears to be increasing, and most of these survivors are children. This may reflect an improvement in emergency transport services. Seventeen previously reported cases of patients surviving atlanto-occipital dislocation for more than 48 hours are reviewed and an additional case is presented. Many of these patients had an excellent neurological outcome. The radiographic criteria necessary for the diagnosis of atlanto-occipital dislocation are discussed. Cervical computerized tomography may confirm the diagnosis when necessary. It is suggested that there are three types of atlanto-occipital dislocation; utilizing this new classification, a rationale for treatment is described. Fusion is favored for long-term stability.

Odontoid upward migration in rheumatoid arthritis. An analysis of 45 patients with "cranial settling"

Lack of correlation between the severity of rheumatoid subluxation of the upper cervical vertebrae and supposed absence of neurological damage has led to the erroneous supposition that this finding is innocuous. Incomplete autopsy studies in rheumatoid arthritis have failed to recognize the cause of death, despite previously proven dramatic occipito-atlanto-axial dislocations. The most feared entity of rheumatoid basilar invagination, namely "cranial settling," is poorly understood. Between 1978 and 1984, the authors treated 45 rheumatoid arthritis patients who were symptomatic with "cranial settling." This consisted of vertical odontoid penetration through the foramen magnum (9 to 33 mm), occipito-atlanto-axial dislocation, lateral atlantal mass erosion, downward telescoping of the anterior arch of C-1 on the axis, and rostral rotation of the posterior arch of C-1 producing ventral and dorsal cervicomedullary junction compromise. Cervicomedullary junction dysfunction has mistakenly been called "entrapment neuropathy," "progression of disease," or "vasculitis." Occipital pain occurred in all 45 patients, myelopathy in 36, blackout spells in 24, brain-stem signs in 17, and lower cranial nerve palsies in 10. Four patients had prior tracheostomies. Four previously asymptomatic patients with "cranial settling" presented acutely quadriplegic. The factors governing treatment were reducibility and direction of encroachment determined by skeletal traction and myelotomography. Transoral odontoidectomy was performed in seven patients with irreducible pathology. All patients underwent occipitocervical bone fusion (with C-1 decompression if needed) and acrylic fixation. Improvement occurred during traction, implying that compression might be the etiology for the neurological signs. There were no complications. Thus, "cranial settling" is a frequent complication of rheumatoid arthritis; although it is poorly recognized, it has serious implications and is treatable.

Modern treatment of the symptomatic os odontoideum

A new surgical procedure for treatment of congenital, symptomatic atlanto-axial instability (os odontoideum ) is described. Two metallic clamps, with an integrated inner spring for maintaining continuous pressure on a cortico-cancellous bone-graft implanted into the interlaminar space, are fixed posteriorly on the vertebral arches C1/2 next to the graft. Because of the initial solid segment-stability external fixation is unnecessary. Posterior interlaminar osteosynthesis prevents late neurological complications caused by a mobile os odontoideum .

Choice of treatment of odontoid fractures

✓ This paper presents a discussion of the diagnosis and treatment of odontoid fractures, based upon the authors' experience with this entity over the last 10 years. Conservative therapy and surgical fusion are compared with respect to efficacy and duration of hospitalization. Arthrodesis is recommended for consideration in the initial treatment of all unstable odontoid fractures.

Posterior atlanto-axial fusion: a new compression clamp for laminar osteosynthesis

A new method of dorsal arthrodesis in patients with atlanto-axial instability of different etiology is described. In three patients solid laminar osteosynthesis C1/C2 was achieved by insertion of an autogenous cortico-cancellous bone graft into the interlaminar space and by a bilateral application of the lately developed metal clamp. The technical principles of the clamp guarantee a permanent pressure on the graft and a solid initial stability in the segment. Additional external fixation and immobilization of the patient are not necessary. Complications as known from other procedures of the atlanto-axial dorsal fusion will be prevented efficiently.

Treatment of odontoid fractures in cancer patients

A series of 18 patients with odontoid fractures due to metastatic cancer were treated at Memorial Sloan-Kettering Cancer Center between 1974--1980. The primary source of cancer was breast (12 cases), lung (two cases), nasopharynx (one case), multiple myeloma (one case), colon (one case), and rhabdomyosarcoma (one case). The clinical features consisted of severe neck pain and neck stiffness in 17 patients; signs of cord compression were noted in only four patients. Tomography and computerized tomography were useful in identifying both the osseous and soft-tissue involvement by tumor. Initial treatment in all patients except those with myelopathy consisted of high-dose steroids, and immobilization in a hard collar. Ten patients were treated with radiation therapy alone; six patients underwent surgical fusion (four before and two after radiation therapy); and two patients died before completion of treatment. Conservatively treated patients were allowed to walk with the support of only a collar following radiation therapy. We believe that the initial management of patients with odontoid fractures secondary to cancer should be high-dose steroids and radiation therapy, unless displacement is marked. Assessment for surgical fusion should be made following radiation therapy, since conservative treatment may suffice in most patients. Early recognition is important so that treatment can be instituted before C1--2 subluxation becomes severe.

Acrylic prosthesis of the fifth cervical vertebra in cervical chordoma. Case report and review of the literature

Description of a two-stage surgical treatment of a case of chordoma of the fifth cervical vertebra mainly affecting the vertebral body. In the first stage the cervical column was immobilized employing a posterior approach and a small portion of the tumour in the right lamina was removed. In the second stage the whole of the body of C5 was removed by an anterior route and replaced with an acrylic prosthesis. The advantages of acrylic resin and the literature on vertebral prostheses are discussed.

Acrylic spinal fusion. A 20-year clinical series and technical note

Methyl methacrylate (acrylic) was used in fusion techniques in 82 patients, most of whom had metastatic disease, between 1959 and 1979. In all cases the acrylic was used to supplement stabilization with Meurig-Williams stainless steel plates or with wire. In cases involving a decompressive laminectomy and excisional biopsy (radical resection of a tumor mass) that required posterior stabilization, acrylic helped to achieve rapid fusion with excellent results. The series included one anterior fusion with acrylic and nine atlantoaxial fusions in patients without tumors. Strict guidelines for selection of patients are outlined. The advantage of acrylic over bone fusion in selected patients is discussed. Careful follow-up studies including autopsy examinations are included. The technique of the use of acrylic is outlined. There was no case of late instability. There was one instance of infection in a patient who was immunodeficient and in whom a combination acrylic and bone fusion was performed. Tissue reaction to the acrylic in autopsy specimens is discussed.

Reconstruction of the atlas and axia with wire and acrylic after metastatic destruction. Case report

The authors describe a method of C1-2 reconstruction by means of wires and acrylic in a patient with metastatic destruction from carcinoma of the rectum. A huge upper cervical tumor together with involved bone had been removed at an earlier operation.

Non-operative management of acute upper cervical injuries

The results of a closed, non-operative type of treatment in acute upper cervical injury have been reviewed, especially as they relate to the use of the halo cast or vest. The morbidity with the use of this device has been minimal and there has been no mortality. Early patient mobilization has been readily achieved and in the case of the Hangman's, Jefferson's, and odontoid fractures, stable solid bony healing has been achieved in nearly all cases. Similar results have been noted in the C-1 arch fracture, as well as the acute post-infectious subluxations of C-1/C-2. In a small number of cases involving traumatic C-1/C-2 and occipital/atlas subluxation, there has occurred a significant incidence of instability, despite adequate closed treatment. This has been likely to be due to the serious ligamentous disruption in these cases and it would appear that surgical fusion may be the preferential form of initial treatment in this group of injuries.

Traumatic atlantooccipital dislocation. Case report

A case of traumatic atlantooccipital dislocation is presented and the literature reviewed. This type of traumatic dislocation is probably produced by violent hyperextension of the upper cervical spine. Cranial nerve injuries and spinal cord injuries are common. Early fusion is recommended.

Posterior cervical fusion in chidren

Six cases of posterior cervical fusion with rib grafts in children are reported. Four of the children had sustained cervical spine injuries in accidents, and two had congenital absence of the odontoid. Three-level fusions (C1-3) were done in four children, and four-level fusions (C1-4) in two. One child died of unrelated causes 3 months after the operation. The other five children have been followed for 5 to 13 years. All are doing well and each has a remarkably supple, stable neck and no neurological deficit.

Traumatic atlantooccipital dislocation. Case report

✓ The successful diagnosis and management of a patient with traumatic atlantooccipital dislocation is reported. Rapid transition from skeletal traction to a four-poster brace followed by appropriately timed surgical stabilization are considered essential.