Ossified pseudomeningocoele following laminectomy: case reports and review of the literature

Rapid ossification of a giant post-operative occipital pseudomeningocele following posterior fossa surgery

Pseudomeningocele formation following posterior fossa surgery is a well-recognised complication, occurring in up to 33% of operated cases in some series. Ossification of a cranial pseudomeningocele is, however, an exceptionally rare event with only three prior reported cases. We present the unique case of a paediatric patient who developed rapid ossification of a giant occipital pseudomeningocele following posterior fossa surgery. An 8-year-old female patient underwent a midline posterior fossa craniotomy for resection of an exophytic brainstem low-grade glioma. Post-surgery, the patient developed pan-ventricular hydrocephalus and a large occipital pseudomeningocele, which initially increased in size despite a successful endoscopic third ventriculostomy (ETV) being performed. At approximately 3 months post-surgery, reduction of the pseudomeningocele was observed with associated prominent ossification of the pseudomeningocele wall on computed tomography (CT) imaging. Surgical excision was subsequently undertaken, and intra-operatively, a large ossified pseudomeningocele was found. Follow-up MRI 1 month later demonstrated almost complete resolution of the pseudomeningocele with an associated reduction in the degree of pan-ventricular ventriculomegaly. This case highlights that ossification of even giant pseudomeningoceles can occur over a time period of just a few months and clinicians should consider ossification whenever a change in size or consistency of a post-operative pseudomeningocele is encountered.

Calcified pseudomeningocele of the lumbar spine: a review

PURPOSE

In this article, we review the English literature of calcified pseudomeningoceles in the lumbar region.

METHODS

A systematic review using the Medline Database using the varied nomenclature for pseudomeningoceles, as well as reviewing the reference lists of relevant article found.

RESULTS

We discuss the different pathological theories on formation of a pseudomeningocele, the formation of a calcified wall and the optimal management for this entity. To date, 17 cases have been described, of which 13 are reviewed here. Calcification of pseudomeningocele is a rare entity and in the lumbar spine this occurs postsurgically. The only predisposing factor is prior surgery to the lumbar spine. Computer tomography, magnetic resonance imaging (MRI) and MRI myelography in combination are the preoperative investigations of choice. The radiological work-up can be preoperatively diagnostic and is important in the surgical planning.

CONCLUSIONS

The treatment is surgicel removal and the decision to treat is based on patient symptoms and correlating these with imaging. There is an average reported follow-up of 1.7 years postoperatively for these patients and the reported outcome after surgery is good.

Ossified pseudomeningocele following Chiari decompression surgery in a patient with Kleeblattschädel deformity

The authors present the case of a 3-year-old child with Kleeblattschädel, or cloverleaf skull deformity, and a Chiari malformation Type I who developed an ossified pseudomeningocele after posterior fossa decompression. To their knowledge, this is the first report of a postoperative ossified pseudomeningocele in a patient with Kleeblattschädel and the only case of an ossified pseudomeningocele located outside the lumbosacral region. A genetic basis for the ossification process seems likely given the child's history of premature cranial suture closure. The authors draw attention to this rare complication and review the available body of literature on this topic.

Pseudomeningocele in communication with the facet joint: demonstration by computerized tomography-arthrography

Pseudomeningocele is an uncommon but well-known complication of lumbar spine operations. Although it is mostly asymptomatic and managed conservatively in most cases, it is claimed as a causative factor of failed back surgery syndrome and requires surgery in some cases. Usually, its diagnosis is confidently done with imaging modalities such as magnetic resonance imaging, computed tomography and myelography. In this report, we describe a case of pseudomeningocele that communicated with a facet joint. The diagnostic approach for this unusual lesion and its probable causes are discussed.

Spontaneous resolution of lumbar pseudomeningocoele

STUDY DESIGN

A case report of spontaneous resolution of a lumbar postdiscectomy pseudomeningocoele.

OBJECTIVES

To suggest the role of nonoperative treatment even in symptomatic pseudomeningocoeles.

SETTING

Withybush General Hospital, Haverfordwest, Pembrokeshire, South Wales, UK.

CASE REPORT

A 65-year-old lady underwent L4/L5 discectomy for lumbar disc prolapse in 1998. As the patient did not have relief of symptoms, an MRI was taken at 1 month following the operation, which showed a residual disc at L4/L5 and a pseudomeningocoele communicating with the subarachnoid space. The patient could not undergo further treatment because of the untimely demise of the surgeon. Over the next 3 months, the symptoms began to improve and the patient was totally asymptomatic and remained so for 3 years. In 2001, she was seen for a recurring leg pain and back pain and an MRI was done, which showed complete disappearance of the pseudomeningocoele but with recurrent disc lesion.

CONCLUSION

Although the current medical literature favours re-exploration and repair of the dural defect in symptomatic pseudomeningocoele, the authors are of the opinion that conservative treatment may have a role in the treatment of the above condition as illustrated by the above example.