Abstract

Background: A postoperative discal/annular cyst following lumbar discectomy may reproduce the symptoms/signs of a recurrent lumbar disc herniation (i.e., back pain and radiculopathy).

Case Description: A 21-year-old rugby player developed leg pain after an uncomplicated lumbar microdiscectomy. The repeat lumbar magnetic resonance imaging confirmed a postoperative lumbar annular/ discal cyst, for which he underwent repeat surgery. The diagnosis was further confirmed histopathologically at surgery.

Conclusion: Although rare, postoperative discal/annular cysts may be potential causes of recurrent postoperative pain and lumbar radiculopathy mimicking recurrent disc herniations.

Keywords: Annular cyst, Back pain, Disc herniation, Discal cyst, Radiculopathy

INTRODUCTION

Postoperative annular cysts may reproduce symptoms and signs (i.e., low back pain and radiculopathy) similar to recurrent disc herniations.[ 3 - 6 ] They are typically unilateral lesions and only rarely bilateral.[ 11 ] Magnetic resonance imaging studies generally show spherical extradural masses with low signal intensities on T1-weighted images and high signal intensities on T2-weighted studies. The optimal management is often repeated surgical intervention for their resection.

CASE PRESENTATION

A 21-year-old rugby player underwent an uncomplicated discectomy at the L4/5 level [ Figure 1 ]. Two weeks later, he returned with recurrent left-sided radicular symptoms/signs. The repeat MR showed an annular cyst at the site of his previous discectomy [ Figure 2 ]. Six weeks after the original surgery, he underwent a second operation for resection of the histologically confirmed discal/annular cyst. After the second surgery, the patient was asymptomatic and joined a rugby training camp 2 weeks later.

Literature review

From 2007 to 2021, we found 20 reports involving 37 patients with similar postoperative discal cysts [ Table 1 ]. These discal cysts likely developed secondary to an iatrogenic annular injury occurring in the course of the original discectomy.[ 2 ] Accompanying histological and epidemiological aspects for this case were comparable to those found in other series.

Figure 1:

(a) Preoperative magnetic resonance imaging (MRI) spine T2-weighted images showing L4–L5 intervertebral disc protrusion, sagittal T2 image (a). (b) Preoperative MRI spine T2-weighted images showing L4–L5 intervertebral disc protrusion, axial T2, image (b).

Figure 2:

Magnetic resonance imaging spine T2-weighted images show discal cyst at L4–L5 level, (a) sagittal images show discal cyst (see arrow) at L4-5 level, (b) coronal images show discal cyst (see arrow) at L4-5 level, and (c) sagittal images.

Table 1:

Summary of case studies.

DISCUSSION

Discal cysts, known as a pre-membranous hematomas, are extremely rare lesions. Notably, they are directly related to synovial cysts, ganglion cysts, and Tarlov perineural cysts.[ 8 , 11 ] Discal cysts are frequently misdiagnosed as recurrent postoperative disc herniations.[ 10 ] On MR, these lesions have a low T1 signal and high T2 signal and typically demonstrate a direct connection between the cyst and the corresponding intervertebral disc. Operative findings document intralesional bloody-to-clear serous fluid within a fibrous cyst wall. Postoperatively, patients’ radicular symptoms/signs typically markedly improve.[ 9 ]

Treatment of discal/annular cysts

Multiple modalities have been utilized to treat the symptoms/signs of discal/annular cysts.[ 7 ] Medical therapy often includes the use of anti-inflammatory agents or corticosteroids. CT-guided aspiration of cysts is frequently attempted and often unsuccessful. Surgery may include microsurgical/endoscopic excision of the cyst and partial hemilaminectomy with microscopic cyst excision (69.6 %) (i.e., direct resection resulting in good clinical outcomes and minimizing risk of recurrence).[ 1 , 12 ] In our case, the patient underwent the latter procedure, and within 2 weeks resumed rugby without further sequelae.

CONCLUSION

Postoperative discal cysts can present with the classical signs and symptoms of recurrent lumbar disc herniation. Optimal management typically includes direct surgical resection rather than often reported failed attempts at cyst aspiration.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Disclaimer

The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Journal or its management. The information contained in this article should not be considered to be medical advice; patients should consult their own physicians for advice as to their specific medical needs.

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