Postoperative pseudomeningocele is a rare, but still existing, complication after spinal surgeries. It may be asymptomatic or presented with back pain, radicular pain or headaches. Many pseudomeningoceles resolve spontaneously, others require revision surgery with dural repair. We present a female patient who underwent duroplasty treatment for a massive postoperative lumbar pseudomeningocele measuring 22.57 cm in length after broad laminectomy. A 71-year-old female with previous thoracolumbar T10-L5 instrumentation surgery, underwent a L2-5 broad laminectomy due to severe canal stenosis at the L2-5 level. Intraoperatively, an accidental spotted durotomy occurred at the level of L4-5. Primary repair was not feasible, so artificial dura was placed. Postoperatively the patient presented with cerebrospinal fluid (CSF) leak, which was treated with external lumbar drain and bedrest. Three months later, our patient presented to our outpatient clinic with a large 15 cm long bulging mass at the surgical site without any neurological deficit. A lumbar CT scan was conducted and a gigantic lumbar pseudomeningocele of 22.57 cm length and 6.29 cm width from the level of T11 to S2 was observed. We performed a revision surgery with duroplasty and there was no recurrence of CSF leak or pseudomeningocele after 7 months follow-up.

Pseudomeningoceles are rare post-operative complications. Although treatment options are controversial, they should be recognized soon enough in order to avoid central nervous infections, neurological deficits and further comorbidities.

duroplasty, post-operative lumbar pseudomeningocele, revision surgery

Pseudomeningocele consists of an extradural collection of cerebrospinal fluid (CSF) after spinal surgeries at the site of the wound and the cause is frequently iatrogenic. The incidence of pseudomeningoceles following spinal lumbar surgeries varies between 0.07%–2%.^[1] Incidental or iatrogenic durotomy has been estimated to occur in 1% to 17% of spinal surgery cases.^[2] They may be asymptomatic or present with back pain, radicular pain, nausea, dizziness or headaches.^[3] Pseudomeningoceles more than 8 cm in size are described as giant pseudomeningoceles and those more than 5 cm as large.^[2] MRI scan is the gold standard for diagnosis as pseudomeningoceles appear hypointense on T1 weighted sequences and hyperintense on T2 weighted sequences respectively.

Management options for pseudomeningoceles are debatable. Small or medium-sized and asymptomatic ones shall be observed and treated conservatively, as they may resolve spontaneously.^[4] In symptomatic patients though, revision surgery may be required to repair the CSF leak and treat caused symptoms. A few case reports are found in the literature and our aim is to add our experience and repair method to the existing literature.^[2–8]

Pseudomeningoceles develop when breach of the dura and the arachnoid layers occurs and CSF leaks into the paraspinal tissues. Unrepaired small dural tears with an arachnoid breach may result in one-way CSF flow like a valve mechanism. This valve mechanism leads to the formation of a cyst surrounded by fibrous connective tissue overtime.^{[6, 8]} When the leak is continuous and there is free space, a fibrous cystic wall develops forming an evolving cavity filled with CSF.

Up to this day, few studies have described lumbar postoperative pseudomeningoceles.^[2–8] Hyndman and Gerber were the first to report post-operative pseudomeningoceles in 1946.^[9] Raudenbush et al. described three cases with compressive pseudomeningoceles and neurological defect which were treated with decompression and dural repair.‌^[2] Solomon et al. reported four cases of large asymptomatic pseudomeningoceles that resolved spontaneously, as three of the patients denied surgical treatment and the fourth showed resolution while waiting for surgery.^[4] Gupta and Narayan also reported two patients with pseudomeningoceles that were treated with dura repair as the defect was easily seen at revision surgery.^[5]

To our knowledge, this is the largest pseudomeningocele of 22.57 cm reported ever in the literature. A previous study of Enke et al. described their case of giant pseudomeningocele and it was measured 8 cm and was the largest lumbar one to date regarding their review of literature.^{[1, 3]} Weng et al. also reported a case series of 11 patients treated for their giant pseudomeningoceles and these were measured between 8-11 cm in length.^[8] Last but not least, Surapaneni et al. reported their case of giant pseudomeningocele that measured 14×2.8 cm and was surgically treated.^[3]

Our patient developed the pseudomeningocele 3 months postoperatively. Several risk factors predispose for pseudomeningocele formation including advanced age, history of previous surgery in the same area, the lumbar area in opposition to cervical or thoracic, resident involvement and the length of the incision.^{[10, 11]} Takahashi et al. retrospectively examined 1014 cases of post-operative pseudomeningoceles and found a slight female predominance, higher incidence in older patients with degenerative spondylolisthesis (9%) or juxtafacet cysts (18.2%).^[11] Smorgick et al. also report older age, previous surgery, and degenerative spine disease as risk factors.^[10] Our patient had all the aforementioned risk factors: advanced age, female sex, two previous surgeries at the very same site for degenerative spinal disease.

However, this delay in development may be attributed to the local use of anti-adhesive agents in order to prevent postoperative adhesions, as they may interfere with fibroblast migration and normal healing.^[4] Additionally, literature demonstrates that when a pseudomeningocele is observed immediate repair is required in order to prevent fistula formation and infection. Our patient proceeded to surgery 9 months after the laminectomy without any signs of infection or fistula formation.

Treatment options remain controversial among surgeons as the site, the size and the neurological defect play key role to the treatment strategy.^[12] Surgical options include observation, surgical direct repair, patch techniques (autografts, allografts or fibrin glue), application of dural blood patch or CSF diversion (lumbar shunt or subarachnoid drain).^{[3, 13, 14]} In our case, we didn’t find a clear CSF leak so we decided to fill the cavity with patches from autograft adipose tissue and artificial dura and fibrin glue followed by meticulous closure of surgical layers. It is difficult to discern which technique is the most efficacious as very few data exist in literature and these data refer successful results.^[2–8] One thing is for sure that prevention is probably the best approach.^[13]

Although pseudomeningoceles are rare postoperative complications, a neurosurgeon should maintain a high index of suspicion when an accidental durotomy occurs intraoperatively and re-evaluate the patient postoperatively. Early recognition is significant for such a complication, because it can cause neurological deficit or be a site of central nervous infection and cause further significant comorbidities. Treatment options are still controversial, nevertheless symptomatic patients should be re-operated as soon as possible.

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The authors have declared that no competing interests exist.