Percutaneous treatment of lumbar synovial cysts with bleomycin: A case report

Abstract

Lumbar synovial cysts (LSC) that protrude into the spinal canal can cause lower back pain, neurogenic claudication, and radiculopathy. Often diagnosed in the elderly population (typically ∼60 years of age) with a slight preponderance for females, their underlying etiology is thought to be due to degeneration of the adjacent facet joint, with the most common location at the level of L4–L5. Treatment of LSC can be conservative (with NSAIDs and physical therapy), percutaneous (with rupture), or surgically (with decompression with or without fusion). Percutaneous treatment of LSC involves rupturing the cyst by injecting it with steroids and local anesthetics. Although this option is less invasive than surgery, multiple studies have documented recurrence with this method and patients eventually undergoing surgical intervention. In this report, we document a case where a patient who presented with a symptomatic LSC underwent successful percutaneous treatment with bleomycin.

Lumbar synovial cysts (LSC) that protrude into the spinal canal can cause lower back pain, neurogenic claudication, and radiculopathy. Often diagnosed in the elderly population (typically ∼60 years of age) with a slight preponderance for females, their underlying etiology is thought to be due to degeneration of the adjacent facet joint, with the most common location at the level of L4–L5. Treatment of LSC can be conservative (with NSAIDs and physical therapy), percutaneous (with rupture), or surgically (with decompression with or without fusion).^1,2

Percutaneous treatment of LSC involves rupturing the cyst by injecting it with steroids and local anesthetics. ³ Although this option is less invasive than surgery, multiple studies have documented recurrence with this method, and patients eventually undergo surgical intervention.^1–6

In this report, we document a case where a patient who presented with a symptomatic LSC underwent successful percutaneous treatment with bleomycin.

Case report

A 47-year-old woman presented with severe back pain and right L4 radiculopathy. The visual analog scale (VAS) at presentation was 10, the worst pain. MRI revealed severe facet arthropathy without listhesis bilaterally at L4–5 and a synovial cyst at right L4–5 projecting into the central spinal canal (Figure 1(A)). Despite six weeks of physical therapy and medical management, symptoms persisted, affecting her work and mobility.

Figure 1.

(A) Under CT guidance, 22 g 3.5-inch spinal needles were percutaneously placed into both facet joints. Contrast was injected, filling the right bilobed L4–5 synovial cyst. (B) Decreased opacification of the cyst and contrast extravasation toward the midline (indicated by arrows) shows synovial cyst rupture. (C) One-month follow-up MRI T2 axial scan, performed due to recurrent symptoms, shows a right L4–5 synovial cyst with morphology different from the prior CT intervention images.

She underwent percutaneous CT-guided synovial cyst rupture and bilateral facet steroid injections under moderate conscious sedation (Figure 1(B)). Initial relief for approximately 1 month was followed by a recurrence of symptoms attributed to a residual cyst identified on a follow-up unenhanced MRI (Figure 1(C)).

Subsequent treatment involved a second cyst rupture procedure, which did not yield significant improvement. A third intervention consisted of injecting 1.5 units of Bleomycin in 25% albumin into the right L4–5 facet joint for a 10-min dwell time, resulting in symptom improvement within a month (VAS 1) and resolution of radiculopathy at three months (VAS 0).

No side effects or complications were reported, and at 18-month follow-up, the patient remained pain-free from her radicular pain. However, she reported ongoing back pain (VAS 4) due to disc herniation (not shown in figures) and facet arthropathy. The patient was without recurrence of cyst-related symptoms (Figure 2).

Figure 2.

Imaging after bleomycin injection (A) one-month follow-up after sclerotherapy shows a decrease in the size of the right L4–5 synovial cyst. (B) Three-month follow-up shows complete resolution of the synovial cyst and left L4–5 facet joint effusion.

Discussion

Previous studies have postulated that LSC most likely derives from degeneration of the adjacent facet joint. Synovial cysts are distinguished from ganglion cysts as they have a characteristic synovial wall lining, whereas ganglion cysts do not. Often occurring at L4–L5, with an incidence of ∼0.6%, they can occur in other locations within the spine. Depending on the severity of symptoms, treatment options for LSC range from conservative therapy with a combination of NSAIDs, bed rest, and/or physical therapy all the way to surgical decompression with or without fusion.^1,5,6

With the first case documented by Casselman, ⁷ the advent of percutaneous intervention via steroids and local anesthetics for the treatment of LSC arrived. A few notable studies that focused on the long-term outcomes of percutaneous treatment of LSCs have demonstrated improved outcomes in ∼50–60% of patients, thus reducing the need for surgical intervention.^1–4 However, a notable percentage of patients still experience cyst recurrence likely from an inability to rupture small cysts due to inadequate pressurization of the joint, thickness or calcification of the cyst wall and thus resistance to pressurization maneuvers, or increased viscosity of the cystic fluid due to previous hemorrhage or elevated protein content. ⁵ Although rare, the complications associated with this minimally invasive technique include dural puncture, subarachnoid space injection, and neural or vascular injury. ⁶

Numerous studies have documented the use of surgical intervention in the treatment of LSC, as its goal is the definitive removal of the entire cyst thereby reducing the likelihood of recurrence. Open surgical decompression with fusion of the culprit facet joints has been the only treatment modality found to have the lowest rate of recurrence of 0% according to one study; however, this is the most invasive option, and its risks cannot be ignored. The most common complications associated with spinal surgery include CSF leak, bleeding, infection, and postoperative instability. One of the larger case series documented a complication rate of ∼6% in 194 patients treated with lumbar surgery. Additionally, one of the largest case series addressing surgical efficacy of surgical decompression for the treatment of LSCs showed that ∼8–9% of patients still endorsed long-term low back pain postoperatively. Since most patients who develop LSCs are elderly and tend to have multiple comorbidities that can negatively impact their candidacy for surgery, other treatment modalities should be considered. ⁵

Bleomycin (first discovered in 1966 by Umezawa et al.) has both antitumoral and antibiotic properties; its mechanism of action involves the breakage of DNA strands via free radical generation. ⁸ Commonly used in the treatment of various cystic lesions, even intracranial cysts such as cystic craniopharyngiomas and Rathke's cleft cyst, due to its efficacy of sclerosing the endothelial lining and low risk–benefit ratio profile, bleomycin has been utilized.^8,9 The senior author's previous experience with using bleomycin to treat a variety of vascular malformations has shown that there is no clinically significant damage to normal surrounding tissues. ¹⁰ The dose of bleomycin used for this patient was determined by the average dose the senior author uses in the pediatric population for vascular malformations located in the head and neck, such as the pharyngeal airway/oral cavity, mucosal lesions, and the orbit. In addition, contrast was not injected before bleomycin injection to avoid dilution of the medication, and prior percutaneous rupture attempts demonstrated communication of the cyst with the facet joint.

In conclusion, although the use of intracystic bleomycin has not been used as a treatment modality for percutaneous treatment of LSC, there is enough evidence in the literature to suggest that its success rate in treating cystic lesions would portend a similar outcome in patients with symptomatic LSC. Further studies would still need to be conducted to evaluate the long-term effects of intracystic bleomycin use as the less-invasive alternative percutaneous treatment for LSC; however, the positive outcomes seen in this case provide hope in utilizing this novel approach moving forward.