Various techniques have been used to achieve C1–2 stabilization, including C1–2 interspinous arthrodesis, 6, 13 posterior transarticular screws, 18 and anterior odontoid osteosynthesis. 3–6, 19 Anterior screw fixation, originally described by Bohler 4 and Nakanishi 19 in 1982, is being used with increasing frequency in a select group of patients with Type II odontoid fractures and may currently be the treatment of choice in this subpopulation. Direct screw fixation of odontoid fractures provides immediate stabilization, avoids inclusion of intact segments in the
Shahin Etebar and David W. Cahill
Daniel M. Sciubba, Joseph C. Noggle, Ananth K. Vellimana, James E. Conway, Ryan M. Kretzer, Donlin M. Long and Ira M. Garonzik
More recently, other forms of C-2 fixation have been developed. Placement of C-2 pedicle screws in conjunction with rod–cantilever constructs, as described by Harms and Melcher, 14 may be a safer and less anatomically restricted means of achieving C-2 fixation than transarticular screws. In addition, Puttlitz et al. 20 reported that C-2 pedicle screw fixation can be substituted for C1–2 transarticular screw placement with no relative compromise to stability or instrumentation stress. Nevertheless, C-2 pedicle screw placement may be technically difficult due to the
Ronald I. Apfelbaum, Russell R. Lonser, Robert Veres and Adrian Casey
motion, which accounts for more than 50% of all cervical spine rotatory motion, and reduces cervical spine flexion—extension by 10%. 42 To overcome the obstacles associated with commonly used odontoid fracture stabilization techniques, many centers have begun to use direct anterior screw fixation in the treatment of these fractures. Direct anterior screw fixation of odontoid fractures is an osteosynthetic technique that can provide immediate stability, promote bone healing, and may preserve normal C1–2 motion. Although this technique provides a potentially ideal
Edward C. Benzel and Nevan G. Baldwin
chance for instrument failure increases as screw size is diminished. To circumvent these problems, a new instrumentation technique, the crossed-screw fixation method, has been developed. The initial clinical results of 11 such procedures performed in 10 patients are presented. This technique facilitates short-segment spinal fixation via the lateral extracavitary approach. This same approach also provides generous exposure for spinal decompression and interbody fusion procedures. Clinical Material and Methods Patient Population Ten patients with
To the Editor: I read the article by Gluf, et al. with great interest (Gluf WM, Schmidt MH, Apfelbaum RI: Atlantoaxial transarticular screw fixation: a review of surgical indications, fusion rate, complications, and lessons learned in 191 adult patients. J Neurosurg Spine 2: 155–163, February 2005). The authors have written an excellent and thorough review of atlantoaxial transarticular screw fixation, which is backed by their rich experience. I fully support their remarks and applaud their work. Nonetheless, I would like to comment on their Fig. 3, which may be
Vassilios I. Vougioukas, Johannes Weber and Kai M. Scheufler
T he advantages of transpedicular screw fixation for three-column control have been well documented. 2, 11, 20, 24, 26, 27 Nevertheless, there have been concerns about placing transpedicular screws in the thoracic region because of the anatomical variability and restricted size of thoracic pedicles. 1, 4, 7, 8, 14, 18, 21, 23 The incidence of thoracic transpedicular screw misplacement when using radiography or fluoroscopy intraoperative imaging-guided thoracic surgery ranges between 3.7 and 38.9%. 3, 5, 9, 12, 13, 15–17 Recent innovations in image
Neill M. Wright
transarticular screw fixation. 21 Axial PS fixation can also be used to incorporate C-2 into subaxial fusion constructs; however, C-2 PS placement remains technically difficult because of the variable location of the foramen transversarium. Although technically simpler to accomplish than transarticular screw fixation because the ideal path of the C-2 PS can be selected independently of the atlas, C-2 PS placement still carries a risk of violation of the foramen transversarium, 5 with possible risk of injury to the VA. The technique of axial fixation with bilateral crossing
Paul Marcotte, Curtis A. Dickman, Volker K. H. Sonntag, Dean G. Karahalios and Janine Drabier
A tlantoaxial instability has traditionally been treated surgically using C1–2 posterior wiring and bone grafts. Initially, C1–2 screw fixation was advocated as a salvage procedure or as an alternative for patients who failed conventional therapy. In 1987, Magerl and Seemann 7 developed an original technique for posterior screw fixation of the C1–2 facets. Until recently, we have treated atlantoaxial instability with operative stabilization using an interspinous bone strut and posterior wiring. 2 A supplemental halo orthosis was applied to augment the
Ronald I. Apfelbaum, Russell R. Lonser, Robert Veres and Adrian Casey
The management of odontoid fractures remains controversial. Only direct anterior screw fixation provides immediate stabilization of the spine and may preserve normal C1–2 motion. To determine the indications, optimum timing, and results for direct anterior screw fixation of odontoid fractures, the authors reviewed the surgery-related outcome of patients who underwent this procedure at two institutions.
One hundred forty-seven consecutive patients (98 males and 49 females) who underwent direct anterior screw fixation for a recent fracture (< 6 months postinjury [129 patients]) or remote (≥ 18 months postinjury [18 patients]) Type II (138 cases) or III (nine cases) odontoid fractures at the University of Utah (94 patients) and National Institute of Traumatology in Budapest, Hungary (53 patients) between 1986 and 1998 are included in this study (mean follow-up period 18.2 months). Data obtained from clinical examination, review of hospital charts, operative findings, and imaging studies were used to analyze the surgery-related results in these patients.
In patients with recent fractures there was an overall bone fusion rate of 88%. The rate of anatomical bone fusion of recent fractures was significantly (p ≤ 0.05) higher in fractures oriented in the horizontal and posterior oblique direction (as compared with anterior oblique), but this finding was independent (p ≥ 0.05) of age, sex, number of screws placed (one or two), and the degree or the direction of odontoid displacement. In patients with remote fractures there was a significantly lower rate of bone fusion (25%). Overall, complications related to hardware failure occurred in 14 patients (10%) and unrelated to hardware in three patients (2%). There was one death (1%) related to surgery.
Direct anterior screw fixation is an effective and safe method for treating recent odontoid fractures (< 6 months postinjury). It confers immediate stability, preserves C1–2 rotatory motion, and achieves a fusion rate that compares favorably with alternative treatment methods. In contradistinction, in patients with remote fractures (≥ 18 months postinjury) a significantly lower rate of fusion is found when using this technique, and these patients are believed to be poor candidates for this procedure.
Kevin T. Foley, Sanjay K. Gupta, Jeff R. Justis and Michael C. Sherman
Standard techniques for lumbar pedicle screw fixation involve open exposures and extensive muscle dissection. The purpose of this study was to report the initial clinical experience with a novel device for percutaneous posterior fixation of the lumbar spine.
An existing multiaxial lumbar pedicle screw system was modified so that screws could be placed percutaneously by using an extension sleeve that would allow for remote manipulation of the polyaxial screw heads and remote engagement of the screw locking mechanism. A unique rod insertion device was developed that linked to the screw extension sleeves, allowing for a precut, precontoured rod to be placed through a small stab wound. Because the insertion device relies on geometrical constraint of the rod pathway through the screw heads, rods can be placed in a standard submuscular position with minimal manipulation, essentially no muscle dissection, and without the need for direct visual feedback. Twelve patients (six men and six women who ranged in age from 23–68 years) underwent pedicle screw fixation in which the rod insertion device was used. Spondylolisthesis was present in 10 patients and nonunion of a prior interbody fusion was present in two. All patients underwent successful percutaneous fixation. Ten patients underwent single-level fusions (six at L5–S1, three at L4–5, and one at L2–3), and two underwent two-level fusions (one from L–3 to L–5 and the other from L–4 to S–1). The follow-up period ranged from 3 to 12 months (mean 6.8 months).
Although percutaneous lumbar pedicle screw placement has been described previously, longitudinal connector (rod or plate) insertion has been more problematic. The device used in this study allows for straightforward placement of lumbar pedicle screws and rods through percutaneous stab wounds. Paraspinous tissue trauma is minimized without compromising the quality of spinal fixation. Preliminary experience with this device has been promising.