C1–2 Intrafacet Bone Grafting and Transarticular Screw Fixation With Endoscopic Spinal Surgery: Report of a Case With Grisel Syndrome

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J Minim Invasive Spine Surg Tech. 2025;10(Suppl 2):S270-S277

Publication date (electronic) : 2025 July 31

doi : https://doi.org/10.21182/jmisst.2025.02117

Luong Minh Quang¹, Tran Chien^,2

¹Spine Unit, Department of Neurosurgery, Saint Paul General Hospital, Hanoi, Vietnam

²Department of Surgery, Thai Nguyen University of Medicine and Pharmacy (TUMP), Thai Nguyen, Vietnam

Corresponding Author: Tran Chien Department of Surgery, Thai Nguyen University of Medicine and Pharmacy (TUMP). Number 284 Luong Ngoc Quyen street, Quang Trung ward, Thai Nguyen city, Vietnam Email: chien.neurosurgeon@gmail.com

Received 2025 February 2; Revised 2025 June 17; Accepted 2025 June 24.

Abstract

INTRODUCTION

Grisel syndrome is a nontraumatic atlantoaxial subluxation after otorhinolaryngologic infections or procedures. Disruption of the bony ligamentous complex at C1–2 causes the C1 vertebrae to swing along C2 dens, resulting in a unique rotational subluxation of C1 over the C2 [1]. According to the literature, this is a rare condition with an approximate prevalence of 1:100,000,000. Most cases are pediatric, 90% younger than 21 years old, and significantly less prevalent in adults [2]. All patients typically respond significantly to conservative treatment, but only a few require surgical management [3]. Open reduction and arthrodesis of the C1–2 vertebrae are indicated for cases that failed to resolve conservatively [4]. This article demonstrates the utilization of spine endoscopy through a posterior approach for direct bone grafting and assisted C1–2 transarticular screw fixation in a case of atlantoaxial subluxation combined with pharyngitis. We seek to contribute insights into the potential benefits of employing endoscopic techniques in treating Grisel syndrome.

CASE REPORT

Before selecting individuals as the study subjects, researchers obtained consent from the patients who were used as subjects.

1. Patient History and Examination

A 75-year-old female with a medical history of diabetes mellitus and corticosteroid abuse developed a sore throat, fever, hyperglycemia, and severe neck pain. She was brought to another hospital to control hyperglycemia and septic shock and was treated for methicillin-resistant Staphylococcus aureus. After 2 months, she was referred to Saint Paul general Hospital because her neck pain got worse from a progressive cervical deformity with a visual analogue score (VAS) of neck pain of 9/10.

On physical examination, the patient’s head was slightly rotated down to the right side, tetraplegia was noted at grade 4 of muscle strength, and deep tendon reflexes in the 4 limbs were 2+. Severe tenderness was elicited on the posterior neck under the craniocervical junction. On admission to our department, blood culture results remained positive. C-reactive protein was 159 mg/L, White blood cell count was 11.4 g/L, and procalcitonin was 0.099 ng/mL.

Imaging study findings concerned a soft tissue phlegm extending from the upper cervical spine to the pharyngeal area. Computed tomography (CT) demonstrated the atlantoaxial disarticulation, causing C1 to rotate slightly to the right side. The left C1 lateral mass eroded, and the right C1 lateral mass was laterally subluxated to C2 (Figure 1A–C). Magnetic resonance imaging (MRI) revealed an infectious process at the left C1–2 joint and the C2 dens with epidural and retropharyngeal extension (Figure 2A and B).

Figure 1.

Preoperative computed tomography. (A) The left C1–2 joint was eroded, and the bony destructive tissue had expanded to the left vertebral artery. (B) On a sagittal view, the C1 ring was subluxated anteriorly. (C) On a coronal view, the C1–2 facets were dislocated bilaterally and were slightly rotated to the right side.

Figure 2.

Preoperative magnetic resonance imaging (MRI). (A) An MRI scan shows epidural and retropharyngeal extension of the abscess in a sagittal view without changes in the spinal cord signal. (B) The infectious area invaded into the left side C1 lateral mass, causing edema and hyperintense signal on an axial MRI view at the level of C1.

2. Operation

A posterior cervical endoscopic approach was planned for C1–2 transarticular fixation with infectious tissue debridement and bone grafting (Figure 3A and B). After successful general anesthesia, the patient was turned adequate prone position without traction. The head was positioned and banded without traction (Figure 3C). We believed that her cervical spine was unstable and still reductable under general anesthesia when the neck was less rigid. After a sterile prep and drape, the skin was marked.

Figure 3.

Preoperative sagittal view of computed tomography shows that it was possible to perform transarticular screw fixation on the right side (A) and left side (B) of the C1–2 facets. (C) Intraoperative position of the patient.

A percutaneous transforaminal endoscopic spine system (Joimax, Germany), tip-flexible bipolar radiofrequency system (Elliquence LLC, USA), Radiofrequency bipolar Vaporflex (Joimax), and endoscopic instruments, including 02 working tubes with handles oblique 30° and 45° (Joimax), were used.

1) C1–2 fixation assisted with endoscopic spine surgery.

Because we planned to insert the percutaneous trans articular screws assisted with full-endoscopic surgery, so we marked the 2 pairs of incisions; the first one was where the midlateral mass line cut the lower part of the C2 facet, the second incision was where the midlateral mass line cut the transarticular screw trajectory (Figure 4A and B). First, we inserted the C2 facet (upper incision) obturator and working sleeve. Under endoscopic view, we approached the C2 descending facet, from the medial to the lateral parts to the prepared insertion screw area. After that, via the lower incision, we penetrated the needle and guidewire into the pars intercularis area of the C2 under C-arm and endoscopic control. Then, we inserted the second working sleeve in place to create and hold a route for screws fixation. During the fixation period, the first surgeon controlled the endoscope and bleeding and prepared the screw location, and the second surgeon managed drilling and screw insertion (Figure 4C–E). We fixed the right-side fist and left side but did not change the position; we all stood on the patient's left side. Surgeons used noncannulated self-tapping lag screws to fix the C1–2 facets bilaterally, the right screw was inserted all the way, but the left side was just inserted halfway through the route. We just created the route by drilling but left the C1–2 joint and C1 lateral mass to be debrided, bone grafted, and then fixed later (Figure 4F and G).

Figure 4.

Intraoperative images. (A) Three-dimensional computed tomography reconstruction of the patient’s cervical spine showing the location of the incision. (B) Location of the incisions. (C and D) Two working sleeves were successfully inserted and checked on the C-arm. (E and F) Drilling and screwing under endoscopic control. (G) The C1–2 facet was fully fixed on the right side, but halfway fixed on the left side.

2) C1–2 facet debridement and bone grafting.

When the halfway insertion of C1–2 was finished, the obturator was replaced into the upper working tube to detach the muscle from the upper part of C2 laminar on the left side. After that, a 30° working sleeve and scope were put in. We started to coagulate and expose the medial edge of the C2 laminar and pedicle to find the upper facet (Figure 5A). Then, the scope and working sleeve was withdrawn slightly to search for the lower part of the C1 lateral mass. The surgeon followed the medial bony bridge to reach out for the C1 lower facet (Figure 5B). The soft tissue around the C1–2 facet was adhesive due to the reaction to the infection and medication effect. We had to dissect carefully to look for and protect the vertebral artery, the left C2 nerve root, and the interfacet space of the C1–2 vertebrae (Figure 5C and D). To prepare bone graft location, we used micro forceps, micro punch to remove the adhesive soft tissue, and a 3-mm diamond high-speed burr to drill out the cortical bone and dead bone for debridement. When the bone graft location was clean, we used a bone chip to fuse the C1–2 facet and later fixed them by standing-by transarticular screw via the other working sleeve under endoscopic control through the first upper tube (Figure 5E and F). After meticulous hemostasis, the 2 working tubes were withdrawn without drainages.

Figure 5.

Intraendoscopic images. (A) The C2 upper part of the pars and facet was covered by adhesive infectious tissue. (B) The lower part of the C1 lateral mass and the infectious soft tissue. (C) The vertebral artery and the C2 nerve root on the left side were exposed safely. (D and E) The C1–2 intrafacet space was well prepared and bone grafted with the artificial bone chip. (F) The left C1–2 transarticular screw was fixed under endoscopic control.

3. Outcome

On day one, after the surgery, the patient was better, with neck pain decreased to VAS 2/10 due to good bone graft and rigid fixation (Figure 6A and B), no fever, and was discharged in stable condition. Months postoperatively, her muscle strength was fully improved without signs of torticollis and infectious recurrence.

Figure 6.

Postoperative x-rays (A) and computed tomography reconstruction (B) of the cervical spine show good bone grafting and rigid fixation of the C1–2 transarticular screws.

DISCUSSION

This paper reports an adult patient with Grisel syndrome, characterized by inflammatory and rotational subluxation of the C1–2 joints. Infective torticollis is an unusual condition that mainly affects children and, even more rarely adults; the incidence rate of the disease is unknown [2]. Most authors recommended early diagnosis based on the symptoms of painful torticollis that occur after an infective cause, such as retropharyngeal abscess, otitis media, tonsillar abscess, or adenotonsillitis [2,5,6]. In our case, signs of fever and sore throat occurred before the patient developed neck pain and upper cervical deformity. Grisel syndrome has also been known to happen after operative interventions of the neck and neck region with adenotonsillectomy, pharyngoplasty, otoplasty, tympanomastoidectomy, and grommet insertion [6]. The pathogenesis of Grisel syndrome is also not specific. The pathogen in our report was methicillin-resistant Staphylococcus aureus. There have been mentioned others like group B beta-hemolytic Streptococcus, Mycobacterium tuberculosis, Epstein Barr virus, or even syphilis [2,6,7]. Early diagnosis of Grisel syndrome is not only based on the identification of pathogenesis but also of the utmost importance due to the neurological complications caused by CT and MRI. The imaging abnormalities that could be found were the atlantoaxial subluxation or rotation [3]. The C1–2 facets were broader and erased in our case. CT examination and MRI revealed the abnormality of soft tissue and neural structures around left C1–2 lateral masses.

The primary treatment of nonneurological, nondeformity Grisel syndrome is conservative. Conservative treatment includes bed rest, hard-collar fixation, antibiotic and anti-inflammation therapy, and muscle relaxants. Delayed detection and medical treatment may result in painful and permanent neck deformity that require surgical indication [5]. Our case had been treated conservatively for more than 2 months before she developed severe neck pain and incomplete tetraparalysis. Pini et al. [8] reported that 96% of pediatric Grisel syndrome were initially managed conservatively. On the other hand, adult Grisel syndrome is more popularly resolved operatively. Kerolus et al. [9] traditionally treated their 2 cases of atlantoaxial instability with C1–2 and C1–4 fusion opening. Yamane et al. [10] described a case with right-side torticollis and quadriparesis that was effectively managed with occipital-C4 traditional fusion. Macki et al. [1] reported on a similar case of adult Grisel syndrome with a late diagnosis who developed right-side painful neck rotation and left arm weakness by the fixation construct from C0 to C4 opening posteriorly. According to the Fielding classification, rigid collar or halo immobilization may be helpful in mild cases with grade I subluxation and no torticollis [1]. In this report, although our patient was detected lately, the rotational deformity was still reducible, and the inflammatory process was only isolated to the left-side atlantoaxial joints. Therefore, C1–2 fusion may be sufficient. In patients with significant subluxation or more severe torticollis and bilateral involvement of occipitoatlantoaxial joints, longer and stronger occipitocervical fusion is likely to provide stability and bony fusion [11].

Regarding C1–2 instability, open reduction, and fusion via posterior C1–2 screw fixation is the preferred fusion technique because of providing high levels of safety and biomechanical stability [12]. Recently, minimally invasive techniques, especially spinal endoscopy, have rapidly emerged due to reducing muscle injury, intraoperative blood loss, and postoperative pain. Some authors preferred transnasal or transoral microendoscopic assisted surgery to fix C1–2 joints, but they had to use stand-alone screw instrumentation or combine it with the posterior approach for fusion demand [13-15]. Aiudi et al. [14] reported complications or cerebrospinal fluid leaks and mucosal incision dehiscence. The challenge to perform anterior microendoscopic C1–2 fusion is to determine the location of the parapharyngeal carotid since they can be retropharyngeal [16].

For surgeons who prefer a posterior approach, C1–2 fixation and fusion can also be done minimally by microendoscopic assistance [17-19]. There were different methods for posterior atlantoaxial fixation, including laminar clamps, wiring, pedicle screw, translaminar screw, and transarticular screw instrumentations. By biomechanical, 2 transarticular screw construct is the same effective as 4 screw construct (C2 pedicle screws with C1 lateral mass screw) for stabilizing the atlantoaxial complex [20]. Even the transarticular screw fixation without wiring could be helpful and safe for both stabilization and fusion of C1–2 joints [17,19]. That is the reason why some authors performed stand-alone transarticular screw fixation under a microscope with endoscopic assistance via a 3-cm incision [17,19]. In our case, the painful subluxation of the atlantoaxial joint failed for conservative treatment because of the facet erosion from the infective inflammation. We had to plan carefully for using interfacet bone grafting and avoiding the vertebral artery from the left side. Some authors use this opening technique to deal with basilar invagination [21,22], but in our case, we used this bone graft approach for the following reasons: (1) this approach could directly debride the infective tissue and help local bone healing, (2) if the infective area was untouched, although we can do posterolateral bone grafting, the infection could continue to grow and lead to nonunion or pseudarthrosis. To prevent injuring the vertebral artery and protect the C2 nerve root while doing the percutaneous C1–2 transarticular screw, we tried to approach as low and medial as possible from the C2 lower facet. In the full-endoscopic stage, we inserted the obturator above the C2 laminar. Then, we found the intrafacet space by carefully dissecting it close to the medial edge of the C2 pedicle. Lvov et al. [17] used the same technique to insert percutaneous transarticular C1–2 screws to treat odontoid fracture without any bone graft. However, at the final follow-up, the author reported the result of the Odontoid process healing; the screws were loosening due to the nonbone grafting technique. Intra-atlantoaxial facet full-endoscopic fusion probably leads to early recovery and good bone healing in our patient.

Grisel syndrome is an unusual condition that must be considered in children and adults with painful torticollis associated with upper respiratory tract infection. We want to emphasize the critical role of early diagnosis and treatment and describe this case as the first case to manage this condition using full-endoscopic techniques.

CONCLUSION

The use of a full-endoscopy in atlantoaxial bone graft and transarticular fixation of C1–2 allows direct visualization of the screw entry point, C1–2 facet, decreases the soft tissue trauma, and can be able to dissect the vertebral artery and C2 nerve root. This successful case doesn’t mean a conclusion of the benefit of this procedure and Grisel syndrome, but it can be an alternative to blind percutaneous surgery via posterior approaches. Further research on full-endoscopic applications for atlantoaxial complex diseases in a more extensive series of patients will allow more informative results.

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