CLINICAL ACUTE PRESENTATION OF LUMBAR FACET JOINT GANGLIA WITH BILATERAL SCIATICA

ABSTRACT Facet joint ganglia are benign cystic lesions located adjacent to a facet joint. The majority is asymptomatic. However, can cause important low-back pain and radiculopathy. Neurogenic deficit, claudication, and cauda equina syndrome have also been reported. The authors report two cases of acute low back pain with bilateral sciatica, dorsal foot dysesthesia, and hallux dorsiflexion/extension deficit, due to the presence of encapsulated cysts adjacent to the facet joints causing a significant reduction of the spinal canal. Urgent surgical decompression was performed in both patients with an uneventful recovery. Symptomatic facet joint ganglia is a highly unusual cause of back pain, although it can present with acute onset of bilateral sciatica and canal stenosis requiring urgent surgical decompression. This paper highlights facet joint synovial as a differential diagnosis of lumbar pain and describes two different surgical approaches with good outcomes. Level of Evidence IV; Case Series.


INTRODUCTION
2][3] Facet joint synovial cyst, ganglion, and ligamentum flavum cyst are described in the literature as varying manifestations of the same entity.][6][7] The first case of radiculopathy caused by a lumbar ganglion was described in 1968 by Kao et al., 8 A history of progressive low--back pain, and radiculopathy are the most common presentation.9,11,12 It can be unilateral, bilateral at a single or multilevel, and the majority are asymptomatic, incidentally found on magnetic resonance imaging (MR). 3,4,7,12,139,14,15 Cauda equina syndrome caused by lumbar facet joint ganglion is extremely rare and warrants emergent surgery. 9,16he authors describe 2 case reports about lumbar facet joint ganglia presented with acute bilateral sciatica and motor-sensitive deficits.

CASE REPORT
The authors presents 2 case reports with a past medical history of low back pain presenting with an acute bilateral sciatica, dorsal foot dysesthesia, and hallux dorsiflexion/extension deficit, within 3 days.
The first case is a 56 years old female with low back pain aggravated over a period of 12 hours with a bilateral foot drop, followed by right lower limb limping 24 hours later, and on the 3rd day, presented to the clinic with a trendelenburg gait.
The second, a 61 years male with worsening of low back pain over a period of 10 days and sudden aggravation within 3 days, initially with limping on the left side with progression to the involvement of both lower limbs.
On examination of the spine, both had a moderate paravertebral spasm with a painful decreased range of motion.Neurological examination showed dysesthesia to the anterolateral aspect of both legs and dorsal feet and no sphincter disturbances or perineal sensory deficits.The motor deficit was evident in the lower limbs with decreased muscle strength at the hallux and toes extensors, gluteus medius, and peroneal muscles.The tibialis anterior muscle had normal strength.(Table 1) Both patients underwent an imaging study.
In the first case, standing lumbar x-rays showed a grade 1 spondylolisthesis at L4 -L5 (Figure 1), and an MR-myelogram demonstrated a compressive intracanalar lesion, causing a secondary stenotic spinal canal at L4-5 (Figure 2).An MR was also performed that showed two large rounded encapsulated cysts adjacent to the facet joints bilaterally, causing a significant reduction of the spinal canal area with a significant compromise of the L5 nerve roots.(Figure 3)     In the second case, the X-ray images showed a degenerative disc disease at L3-L4, L4-L5, and L5-S1 without changes in vertebral body alignment (Figure 4).The MR showed a right-sided L3-L4 and L4-L5 foraminal disc herniation, compressing the nerve roots and a ganglion adjacent to the L4-L5 left facet joints producing acute critical canal stenosis and at L5-S1 a central disc protrusion.(Figure 5) In the face of these clinical and imaging findings, both patients underwent surgical spinal canal decompressing and ganglia excision.
The surgical strategy in the first case was a L4 laminectomy with L3-4 and L4-5 flavectomy, with bilateral ganglia excision.Because of the segmental instability at L4-L5 shown on the pre-op radiographs and the extensive decompression, a postero-lateral instrumented L4-L5 fusion was performed.(Figure 6) The second case was treated with L3, L4, and L5 left hemilaminectomy and hemiflavectomy, L4-L5 foraminotomy, and ganglia excision.(Figure 7) Postoperatively, both patients presented an improvement in pain and neurologic deficit.Complete motor and sensory recovery was noted at 8 weeks in case 1 and at 5 weeks in case 2.

DISCUSSION
This pathology prevalence is not well-known.13]16 Facet joint arthritis generates effusion that causes protrusion of the synovial membrane through defects in the joint capsule.0][11] Ulus et al. found a prevalence of 75% facet arthropathy and 37,5% spondylolisthesis. 2 The clinical findings depend on its location, volume, and relation to neural structures. 4,9Nevertheless, despite the symptoms being often correlated to the side of the synovial cyst, Lyons et.al., reported that 21% of patients with large ganglia present with bilateral or contralateral symptoms. 7his case series describes 2 patients with acute bilateral sciatica, sudden limping, and motor weakness at the gluteus medius, peroneal muscles, hallux, and toes extensors.These clinical examination points to a bilateral L5 nerve root deficit, and we must consider it as a differential diagnosis of disc herniation, lumbar stenosis, facet joint syndrome, pathological fracture, or another intracanalar lesion.This sudden onset presentation requires a prompt investigation.
Plain radiographs are useful in assessing spinal segmental instability and help to exclude other conditions, such as spondylosis, degenerative spondylolisthesis, and metastatic lesions. 47,12 They are usually described as round or oval collections arising from the medial aspect of the facet joint and projecting beyond the visible margins of the joint with hypointense "inner cores" on T1-weighted MR sequences and hyperintense centers with hypointense rims on T2-weighted sequences. 1,3,5,9,12,15,16owever an accurate MR diagnosis can be difficult because the ganglia content exhibits variable signal intensity. 4,12Apostolaki et al. describe four patterns of MR in their study. 12he imaging exams evidence an L4-L5 "acute" canal stenosis, consistent with the clinical exam.In the first case, the acute onset could be associated with intracystic hemorrhage and acute distention of the cyst in an unstable segment due to spondylolisthesis.An association between the acute distension of the cyst and acute disc herniation could be the explanation for the second case. 11,12,15lthough conservative treatment shows temporary improvement, some authors suggest doing it for 6 months before considering surgical options. 4Conservative management includes bed rest, analgesia, and physical therapy.However, a more invasive attitude can be adopted with CT-guided intra-articular corticosteroid injection, needle aspiration of cystic contents, or percutaneous rupture. 4,5,9,14,16urgical excision and decompression is the preferred treatment in symptomatic patients.However, there is no consensus, and therefore a few surgical strategies have been reported.The gold standard technique reported was laminectomy and flavectomy, although it has been associated with ganglia recurrence.Morishita et al., reported that 4.69% of the segments treated with posterior decompression surgery without fusion developed recurrent symptomatic facet joint, particularly those submitted to bilateral posterior decompression. 13he development of facet joint ganglia within the early postoperative period supports the instability hypothesis as the major role in the development of this pathology. 7,9,10,13,17The introduction of minimally invasive techniques made it possible to overcome this problem, allowing less damage to the posterior stabilizing structures.Lalanne et al. recommended an individual evaluation to assess the segment's instability and the need for instrumented fusion. 99][20] On the contrary, patients with evidence of prior instability on standing radiographs are more likely to be treated with decompression and posterior instrumented spinal fusion. 9,16oth patients underwent surgical treatment.A grade 1 spondylolisthesis at L4-L5 level was reported in the first case and a posterolateral instrumented fusion was performed.Still, the other patient underwent a hemilaminectomy and decompression as a stand-alone procedure.

MR and CT
Regarding postoperative results, both patients had an uneventful recovery, pain improvement, and neuro deficits.

CONCLUSION
To conclude, a symptomatic facet joint ganglia is a rare condition and its acute presentation is even more exceptional.When it occurs, a comprehensive objective examination should be performed in order to define possible differential diagnoses and guide subsequent investigations.MR is the imaging of choice as it allows the identification of this pathology and the associated degenerative changes that can lead to canal stenosis.Urgent surgical decompression is mandatory and the surgical technique must be individualized for each patient.

Figure 1 .
Figure 1.X-ray images of the first case.A -X-ray in AP view.B -X-ray in lateral view of a Grade 1 spondylolisthesis at L4-L5 level, without indirect signs of lumbar spinal stenosis.

Figure 2 .
Figure 2. MR-myelogram of the first case with an spine canal lesion at L4-5 level.

Figure 3 .
Figure 3. MR of the first case with two large cysts adjacent to the facet joints bilaterally at L4-L5 level.A -MR T2 sagittal views.B -MR T2 axial views.

Figure 4 .
Figure 4. X-ray images of the second case.A -X-ray in AP view.B -X-ray in lateral view with degenerative disc disease at L3-L4, L4-L5, and L5-S1.
Each author contributed individually and significantly to the development of the manuscript.CC and JM were the main contributors to writing the manuscript.LB, JM, and JC performed the surgery, followed up the patients, and collected clinical data.CC, AB, NL, and JM performed the literature search, revised the manuscript, and contributed to the intellectual concept of the study.

Table 1 .
Motor function and reflexes examination.