Krantiveer Vasantrao Narayanrao Naik Shikshan Prasarak Sanstha's, Institute of Pharmaceutical Education & Research, Canada Corner, Nashik - (422002) Maharashtra, India
Due to impingement upon the corticomedullary junction, retro-odontoid pseudotumor typically cause cervical neck pain or myelopathy. These tumours are characterized by soft tissue development surrounding the longitudinal ligament of the axis. As a sign of atlantoaxial instability, retro-odontoid pseudotumor development is caused by aberrant granulation tissue development, usually posterior to the odontoid process. Dorsal decompression, ventral decompression (both transoral and trans nasal), and other surgical procedures are covered. No more decompression was carried out during the posterior C1-2 fixing procedure. During a year of posterior fixation, there were no noticeable signs, and a follow-up MRI revealed that the ROP had completely resolved with C1-2 bone fusion. With only C1-2 fusion and no decompression, the ROP with C1-2 instability may be completely cured. Discuss about the surgical methods used in the past and now to reduce and eventually reverse a retro-odontoid pseudotumor and pannus. A mass lesion located along the dura posterior to the odontoid process is called a retro odontoid pseudo tumour. Cervical retro-odontoid pseudo myelopathy, a neurological disease, was one of the surgical reasons for the high cervical lateral approach. rheumatoid arthritis-unrelated tumour that is severely squeezing the spinal cord. Ligaments play a crucial part in the CCJ's mechanical stability. Particularly important for controlling the CCJ are the longitudinal and alar ligaments, which connect to the posterior odontoid process. Soft tissue proliferation, also known as pseudotumor, in the area of the transverse ligament of the atlantoaxial (AA) junction has been associated with a wide spectrum of congenital and acquired disorders.
This retro-odontoid pseudo tumoral lesion has been described by multiple authors as synovial cysts, deteriorated transverse ligaments, herniated discs, ganglion cysts, and damaged transverse ligaments. tendons or imitation gout (Cai et al.,2001) (Griesdale et al.,2004). The ligaments surrounding the atlantoaxial junction, leading to long-term inflammation and the development of granulation and fibrotic tissue (Robles et al.,2019) (Fiani et al.,2021). There have been about 70 occurrences of synovial lesions or ganglion lesions at the C1–C2 level documented in the past; all of these cases were connected to atlantoaxial dysfunction or trauma. (Theodotou et al.,2016) (Yang et al.,2021). In 1974, Anderson and D'Alonzo created the first three categories for odontoid fractures connected to pannus development. (Sinha et al.,2017). According to a 1991 theory by Crokard et al., injury to the C1–C2 ligamentous structures causes chronic atlanto-axial instability, which can then cause a retro-odontoid pannus to form. Degenerative articular cysts and non-inflammatory retro-odontoid pseudotumor have been reported in very few occurrences in recent times. (Crokard et al.,1991) (Isono et al.,2001) (Joly et al.,2004) (Tanaka et al.,2010) (Cihanek et al.,2007) (Ito et al.,2000). The brainstem may develop syringomyelia as a result of mechanical displacement, such as morphological changes, (Thornburg et al.,1999) (Spetzler et al.,1988).
Pseudotumor formation can be indirectly caused by a multitude of etiologists. The most common causes are congenital abnormalities such neurofibromatosis, Down syndrome, and Marquee syndrome, as well as rheumatoid arthritis (RA) and severe trauma. When RA is present, inflammatory synovial joint infiltrates cause the posterior longitudinal ligament (PLL) to buckle, which results in the formation of pannus. (Goel et al.,2015). While the method described here may not be novel, it can be regarded as a novel approach to treating retro-odontoid pseudotumor, which are increasingly common in senior patients. Its inclusion in the surgical strategy of posterior cervical fusion or decompression alone is still up for debate (Suetsuna et al.,2006) (Takami et al.,2007). Early detection of cervical myelopathy in the context of an odontoid pseudotumor combined with timely surgical assessment can lower morbidity and enhance results related to spinal cord compression. Furthermore, in order to support patients in maintaining their initial functional state, early intervention is essential (Bakhsheshian et al.,2017).
METHOD AND TECHNIQUES
1] Patients:
Included were consecutive adult (over 20 years of age) patients who underwent surgery between April 2006 and March 2019 for nonrheumatic pseudotumor. Patients who received treatment for rheumatoid pseudotumor in the same time frame served as the control group. Physicians made the diagnosis of rheumatoid arthritis and gathered data from medical records. Patients who underwent surgery and had a follow-up period shorter than a year were not included. The medical data that was collected included age, sex, previous medical history, cervical pain, neurological signs and symptoms, radiological findings, surgical procedures, difficulties, duration of follow-up, and postoperative symptoms. Neurological signs and symptoms were evaluated using the grip strength test, the grasp-and-release test, the patella tendon reflex, and the modified Rankin Scale (MRS) scores. (Ono et al.,1987). Between 2009 and 2012, five patients who did not have inflammatory illnesses received treatment. All of the patients had irregularities at the cranio-cervical junction and/or lower cervical spondylotic degeneration. There was no proof of atlanto-axial instability. The pre- and post-operative Nurkic scores, pre- and post-operative X-rays, CT scans, and MRIs were all part of the clinical and radiological examination. In one instance, a pannus eggshell calcification was visible on a CT scan. In instances of C0–C1 fusion, all patients had either an occipitocervical fixation (two patients) or a C1–C2 fixation (C1 lateral mass and C2 isthmus-pedicle screws). (Barbagallo et al.,2013). Over the course of three months, a female patient, age 83, developed chronic cervical myelopathy. There was a cystic odontoid mass with a distinct retro-odontoid compressive mass, as shown by computed tomography and magnetic resonance imaging investigations. The transoral extraction was a revolutionary, minimally invasive procedure. Histologic validation of CPPD was acquired. (Klineberg et al.,2014). Three patients (two females and one male) with a cystic retro-odontoid pseudotumor that significantly compressed the spinal cord and was unrelated to rheumatoid arthritis were included in this investigation. 74.7 years old was the mean (range, 73–77 years old). The neurosurgical cervical spine scale (NCSS) was used to evaluate the state of the nervous system.15) At least three months following surgery, a postoperative functional assessment was carried out. (Arima et al.,2019). With the C-2 nerve root sectioned at the C-2 ganglion, the posterior aspect of the C1-2 facet joint was revealed. Anatomical cartilage of the C1-2 facet Bone grafts were placed into the joints after the joint was removed using a high-speed drill. Fig. 1). (Goto et al.,2002).
Figure 1: Photos taken during surgery demonstrating the identification and mobilization of the right C-2 nerve root and the placement of a bone graft into the right C1-2 facet joint following the sectioning of the C-2 nerve root.
Surgical Technique:
Cervical retro-odontoid pseudo myelopathy, a neurological disease, was one of the surgical reasons for the high cervical lateral approach. rheumatoid arthritis-unrelated tumour that is severely squeezing the spinal cord. Cases exhibiting clinical symptoms or indicators associated with instability at the C1/2 joints were not considered surgical candidates. In the initial weeks following surgery, a cervical collar was utilized to lessen the patient's suffering. Had slight paralysis of the face and spinal accessory nerves on the side of the surgical approach, which resolved completely approximately a month following the procedure. In every case, the final functional assessment revealed an acceptable or satisfactory level of functional recovery. (Takami et al.,2017). The C-1 lateral mass screw entered the body at the point where the lateral mass and inferior aspect of the C-1 arches met (Fig. 2). The A screw was advanced about 10 degrees medially and superiorly toward the C-1 anterior tubercle while being observed under a fluoroscope. The screws had a diameter of 3.5 mm and a length ranging from 8 to 26 mm (Fig. 3). The C-1 lateral mass screw and the C-2 pars/pedicle screw (SYNTHES, West Chester, PA, USA) were firmly fastened using a rod. The patient was immobilized on the first postoperative day and had to spend several weeks wearing a soft collar. (Takami et al.,2017 a)
Figure 2A: Photo utilizing a spine model to illustrate the entrance locations for the C-1 lateral mass screw (a), C-2 pedicle screw (b), and C-2 pars interarticularis screw (c). B: A photo displaying the intended sagittal plane screw paths for the C-2 pedicle/pars interarticularis screw and the C-1 lateral mass screw. An arrow points to the bone grafts inserted into the facet joints of the C1-2
Figure 2B: An image displaying the titanium rods and screws for cancellous bone. The screw has a partially moveable head
Patients were put under general anaesthesia and made to lie horizontal. All patients had posterior fixation, with the exception of those who were severely disabled and at a higher risk of perioperative problems. Altitudinal interval and cervical alignments were taken into consideration during a neurosurgery meeting that determined whether to perform C1-2 fixation or occipitocervical (O-C) fixation on an individual basis. (Niwa et al.,2021). To realign C1 and decompress the spinal cord, the neck was positioned in the neutral position. Patients with AAD who experienced severe spinal cord compression even after being repositioned in the neutral neck position also underwent C1 laminectomy. The iliac crest bone or the C1 lamina were used to create autologous bone transplants (Niwa et al.,2021 a).
Pathophysiology:
Soft tissue proliferation, also known as pseudotumor, in the area of the transverse ligament of the atlantoaxial (AA) junction has been associated with a wide spectrum of congenital and acquired disorders. (Fiani et al.,2021). Three subtypes of RA-associated pannus have been discovered by histopathology; they are known as inflammatory, mixed, and fibrous pannus, respectively. Hyper vascular, hypo vascular, and fibrous pannus are the other names for these subtypes. (Shi et al.,2019). Type II odontoid fractures, which happen where the odontoid base and axis body meet, are the most prevalent kind linked to non-union or malunion. A fibrous mass of soft tissue surrounds the fracture site as a result of malalignment and increased motion at the broken section, which increases the risk of chronic irritation. During 2007. (Anderson and D’ALONZO et al.,1974) (Sinha et al.,2017). Retro-odontoid pseudotumor may occur as a result of inflammatory deposits and amyloid growth. (Wada et al.,2015).
Last but not least, retro-odontoid pseudotumor has been linked to pigmented villonodular synovitis (PVNS) in previous case reports. Up to 36% of cases of PVNS, a proliferative, destructive, non-malignant tumour of synovial membranes, can impact the cervical spine. (Finn et al.,2007) (Roguski et al.,2014). Furthermore, deposition illnesses such gout, amyloid arthropathy, and calcium pyrophosphate dihydrate deposition disease (CPPD) can induce pseudotumor. The underlying disease process of CPPD is called chondrocalcinosis, and it is brought on by calcium pyrophosphate dihydrate crystals that accumulate in the synovium, capsule structures, and tendons (Sekijima et al.,2010).
CLINICAL DISCUSSION
A non-neoplastic lump in the retro-odontoid area that affects seniors is called a pseudotumor. In terms of pseudotumor pathogenesis. (Sze et al.,1986). Eleven of these thirteen instances happened at the craniovertebral junction (CVJ), while two happened at the lower tailbone. This high frequency of dural penetration at the CVJ was not mentioned in any of the previous research. A few earlier investigations have described an unusual dura mater morphology at the CVJ. The two layers that comprise the posterior wall of the thecal sac are the rectus capitis tendon and the outer layer of the cranial dura mater. (Ito et al.,2020). The recommended technique for atlantoaxial fixation has been the C1-2 transarticulaire screw placement; when combined with autologous bone graft and cable, which has a high fusion rate, can completely stop motion at the C1-2 joint. (Magerl et al.,1985) (Dickman and Sonntag et al.,1998) (Haid et al.,2001) (Haid et al.,2001). The AAI's persistent mechanical stress causes transverse ligamentous hypertrophy and recurrent tears, which lead to the development of reactive tissue with fibrous granulation. Most patients have no symptoms at all, though they may report persistent cervical pain. When ROP reaches a serious and mature stage, it may compress the cervical spinal cord and cause neurological problems. Occasionally, a further incident in our case, a ground-level fall can decompensate the clinical state. Pathophysiological, fibrocyte-rich tissue is between the dens and the cross-sectional ligament, or between the odontoid process and the anterior arch of the C1 (Goel et al.,2004) (Yamaguchi et al.,2006). Because the pathology was obvious, total excision of the mass was formerly thought to be the best course of action for treating pseudotumor. Total excision has been achieved using the transoral method, as said by Crokard (Sinha et al.,2017a). The transoral method was thought to be the best course of action for removing the retro-odontoid mass and decompressing the neural structures in individuals with symptomatic spinal cord compression. (Crokard et al.,1986) (Moskovich and Crockard et al.,1990). There isn't a single recommended treatment plan for retro-odontoid pseudotumor. (Sinha et al.,2017b). Took a transoral technique and directly excised the pseudotumor. Previous research has described retro-odontoid pseudotumor as a reactive mass caused by mechanical stress resulting from atlantoaxial instability or ankylosis in the mid and lower cervical spine. For this reason, posterior fusion, such as O-C2 fusion or O-C4 fusion, has been considered the best course of action for halting the pathology's development. Furthermore, the retro-odontoid pseudotumor regressed and the neurological impairments improved following posterior fusion. (Yoshida et al.,1999) (Chikuda et al.,2009). Ligaments play a crucial part in the CCJ's mechanical stability. Particularly important for controlling the CCJ are the longitudinal and alar ligaments, which connect to the posterior odontoid process. (Werne et al.,2019). Though it is still debatable whether the procedure should be included in the surgical approach of posterior cervical fusion or relaxation alone, it can be thought of as an innovative solution for retro-odontoid pseudotumor, which is growing more common in senior patients (Suetsuna et al.,2006a) (Takami et al.,2007a).
Operative Technique:
1] Ventral Decompression:
Many different disorders can cause compression of the front upper cervical spinal cord. The most frequent consequence of compression of the ventral chord that necessitates surgical intervention is the development of an inflammatory pseudotumor. (Joaquim et al.,2019) (Landi et al.,2013) (Oseni et al.,2016). The anterior region of the upper cervical spinal cord can become compressed due to a number of different diseases. Growth of an inflammatory pseudotumor is the most common complication requiring an operation for compression of the ventral cord (Abdelgawaad et al.,2018).
It was demonstrated that the shift in degrees of rotation at C1/C2 caused odontoidectomies to create a redistribution of the axes along which rotation took place. After odontoidectomies, rotation at C1/C2 was reorganized throughout C2's body, resulting in a significant disruption of the body's inherent biomechanics. Although it is much less common, Fig. 3 presents an exemplary case of partial resection of the odontoid and C1. (Fiani et al.,2021a).
Figure 3: An example of a patient with a history of rheumatoid arthritis who presents with bilateral hand paralysis and severe posterior neck pain. (A) Retro-odontoid pannus and compressive upper cervical spinal cord stenosis are seen on preoperative midsagittal T2-weighted magnetic resonance imaging (MRI), in addition to sub axial cervical stenosis. Postoperative trans nasal excision of pannus is shown on (B) postoperative midsagittal T2-weighted MRI. Sub-axial cervical stenosis necessitated additional C1-6 decompressive laminectomy, occipital-T2 instrumentation, and fusion.
There are substantial differences between the access ranges offered by TO and EE techniques. For EE operations, the inferior border is the nasopalatine line (NPL). Even while each patient's NPL may differ depending on their spinal level, the TO technique offers more caudal access than EE surgery. When compared to EEA, the superior border of the TO method is limited. However, this limit can be increased by dividing the hard and soft palates. Conversely, this could lead to velopharyngeal insufficiency (VPI). (Fujii et al.,2015) (Perrini et al.,2014) (Komotar et al.,2012). Rates of VPI in both operations may be underreported since the pathophysiology involves iatrogenic fibrosis of the palate's soft tissue and pharyngeal wall, which may not appear medically for three to six months after surgery. This study showed that underlying illnesses other than rheumatoid pannus could also require surgical treatment. (Shriver et al.,2016)
2. Dorsal Decompression:
Retro-odontoid pseudotumor with symptoms can arise from a variety of aetiologies that do not include intrinsic instability of the cervical or CVJ. In these cases, the posterior treatment alternatives include immediate lesion excision or decrease of the lesion by posterior decompression without fixation. The former has been proven using laminectomy or C1 laminoplasty without the need for any fusion or instrumentation. (Suetsuna et al.,2006b).
Detailed three instances where this method was used to effectively resect nonrheumatic retro-odontoid pannus. Within a minimum of three months and a maximum of two years following surgery, all three patients showed improvement in their symptoms and no recurrence. This approach has several limitations: it cannot achieve complete resection when necessary; it is advised to limit caudal extension to the C3 level; it has a deep and narrow field of view; it poses a risk to the vertebral artery, facial and accessory nerves, and their associated branches; and it becomes necessary to respect the C2 nerve root when it crosses the operative field. But the posterolateral method can still be a good choice for lesions big enough to provide a noticeable mass impact and need direct excision for decompression. (Oohori et al.,2004)
As far back as 1910, a posterior transmural technique for the excision of a lesion situated ventrally was documented in the literature. (Zileli et al.,2020). For a unilateral hemilaminectomy to remove an intradural lesion. Since then, a posterior trans dural technique has been used to treat various extradural ventral lesions such as cysts, retro-odontoid pseudotumor, and herniated discs. (Schomacher et al.,2020)
POSTERIOR INSTRUMENTATION FOR TREATMENT OF PSEUDOTUMOR FORMATION
1] Occipital-Cervical Fusion:
More regression as compared to both anterior and circumferential techniques, as well as similar therapeutic gains in Nurkic score, all while reducing time to recovery and surgical problems (Bydon et al.,2015). Due to the previously described subluxation, individuals usually appear with cases of acute neck discomfort and myelopathy, which might progress to untimely death. (Larsson et al.,1989) (Boden et al.,1993). Odontoid process erosion may also be seen on MRI, which would further suggest posterior instrumentation during surgery because of possible C1-2 instability (Larsson et al.,1989a). When doing occipital surgical fusion, the surgeon uses intraoperative monitoring to evaluate tissue damage while gradually decompressing the medulla to prevent additional pseudotumor progression and to improve neurological results (Sekijima et al.,2010a).
2. C1–2 Fusion:
One of the most frequent areas where pseudotumor development occurs is the C1-2 synovial lining surrounding the odontoid. (Sekijima et al.,2010b). The goal of stabilizing the C1-2 level of the spinal axis is to eventually cause the inflammatory granulation tissue to retreat before neurological symptoms get worse or manifest. (Young and Boyko et al.,2002).
Reducing the longitudinal ligament's gradual deterioration, which would cause the atlas to move forward across the axis and ultimately result in irreversible atlantoaxial kyphosis, is another reason for C1-2 fusion. (Kandziora et al.,1999). The primary advantage of C1-2 fusion is that, compared to transoral/trans pharyngeal resections, it takes a less aggressive strategy and may result in an adequate degree of pseudotumor reabsorption, which could reduce or, in certain cases, completely eliminate neurological signs following surgery as measured by the Nurkic scoring scale. (Bydon et al.,2015a) (Lansen et al.,1990).
CONCLUSION
The pseudotumor was quickly eliminated with occipitocervical fusion, and the clinical symptoms improved favourably. When atlantoaxial causes this illness Joint overload or instability should be treated concurrently with fusion, even if preoperative dynamic imaging shows no signs of instability. Occipital-cervical fusion is the recommended anatomical procedure. There are various justifications for stabilizing C1-2 joints, as well as techniques for doing so, each with a unique set of risks and surgical challenges. Selecting the optimal procedure from the many that have been suggested is challenging because surgeons find it difficult to get enough experience in all of the techniques to make an informed decision. As a result, the theoretical assessment offered here is logical, and the conversation is really beneficial. The pros and cons of placing individual C-1 and C-2 screws versus C1-2 transarticulaire fixation are examined in this patient group afflicted with a retro-odontoid pseudotumor linked to persistent atlantoaxial instability.
REFERENCE
Prerana Borade, Mayuri Jagtap*, Avinash Darekar, Retro-Odontoid Pseudotumor: A Rare Entity, Int. J. Sci. R. Tech., 2024, 1(3) 31-40. https://doi.org/10.5281/zenodo.13885121
10.5281/zenodo.13885121
