Arq Neuropsiquiatr 2007;65(2-A):279-282

Hospital São José / Complexo Hospitalar Santa Casa de Porto Alegre RS, Brazil: 1Medical, Resident in Neurosurgery at Hospital SãoJosé - Complexo Hospitalar Santa Casa (HSJ/CHSC). 2N e u ro s u rgeon at Hospital Tacchini - Bento Gonçalves, RS. 3Medical Student,Complexo Hospitalar Santa Casa / Fundação Faculdade Federal de Ciências Médicas de Porto Alegre (FFFCMPA). 4N e u ro s u rgeon atHSJ-CHSC.

Received 2 August 2006, received in final form 27 October 2006. Accepted 18 December 2006.

D r. Arthur de Azambuja Pereira Filho - Avenida Oscar Pereira 3008 - 91710-000 Porto Alegre RS - Brasil. E-mail: art h u r p e re i r a f i l h o @gmail.com

SYMPTOMATIC THORACIC SPINAL CORD COMPRESSION CAUSED BY POSTSURGICALPSEUDOMENINGOCELE

Arthur de Azambuja Pereira Filho1, Gustavo de David2,Gustavo de Azambuja Pereira Filho3, Albert Vincent Berthier Brasil4

ABSTRACT - We re p o rt the first case of symptomatic thoracic spinal cord compression caused by postsur-gical pseudomeningocele. A 49-year-old man sought treatment for pro g ressive loss of strength in the low-er extremities ten months after full neurological re c o v e ryfor a thoracic (T11) intradural-extramedullaryschwannoma. Magnetic resonance imaging revealed a postsurgical thoracic (T11-T12) pseudomeningo-cele. The surgical approach showed an inadequate dural closure with spontaneous cere b rospinal fluid fis-tula. The defect was sealed with suture, muscle and biological glue covering. The patient had a good re c o v-e ry. Pseudomeningocele must take part of the diff e rential diagnosis of myelopathy after thoracic spinesurgery.

KEY WORDS: pseudomeningocele, spinal cord compression, myelopathy.

Compressão medular torácica sintomática causada por pseudomeningocele pós-operatória

RESUMO - Relatamos o primeiro caso de compressão medular torácica sintomática causada por pseudo-meningocele pós-operatória. Paciente masculino, 49 anos, apresentou perda pro g ressiva de força nase x t remidades inferiores dez meses após recuperação neurológica completa de ciru rgia para remoção deschwannoma intradural-extramedular torácico. A ressonância magnética dorsal revelou pseudomeningo-cele (T11-T12). A abordagem cirúrgica mostrou fechamento dural inadequado com fistula liquórica espon-tânea. O defeito foi corrigido com sutura, músculo e cola biológica. O paciente teve boa evolução pós-operatória. Pseudomeningocele deve fazer parte do diagnóstico diferencial de mielopatia surgida apóscirurgia na coluna dorsal.

PALAVRAS-CHAVE: pseudomeningocele, compressão medular, mielopatia.

Pseudomeningoceles are defined as extraduralcollections of cere b rospinal fluid (CSF) with no duralcovering, which usually result from an inadvertent me-ningeal tear or inadequate closure during spinal sur-g e ry1 - 4. Most pseudomeningoceles remain embed-ded in the paraspinal soft tissue and cause no symp-t o m s5. Pseudomeningocele is an extremely rare causeof spinal cord compression. Few cases have been re-p o rted in the literature and in all of them the spinalc o rd compression was located in the cervical re g i o n6 - 9.

We describe a case of symptomatic thoracic spinalc o rdcompression caused by postsurgical pseudome-ningocele. To our knowledge, this is the first re p o rt-ed case of a thoracic postsurgical pseudomeningo-cele causing symptomatic spinal cord compression.

CASEH i s t o ry and examination – A 49-year-old Caucasian man

sought treatment after experiencing the development ofp ro g ressive motor loss in the lower extremities for the lastt h ree months. The patient had undertaken a previous neu-ro s u rgical approach for a thoracic schwannoma ten monthsearlier, with a history of full neurological recovering afterthe surgery.

The patient’s neurological examination showed de-c reased strength in both the lower limbs (he could walkwith aid), with bilateral Babinsky sign, without sensory,bowel or bladder findings. All other aspects of neurologi-cal examination were intact.

The palpation of the operative wound showed noabnormality.

N e u roimaging investigation – Magnetic resonance imag-

280 Arq Neuropsiquiatr 2007;65(2-A)

ing (MRI) revealed a postsurgical thoracic pseudomeningo-cele extending from T11 to T12 (Fig 1).

S u rgical treatment – An external cere b rospinal fluidlumbar drain was placed preoperatively and kept closedduring all the surgical pro c e d u re. The previous wound wasreopened and a high tension encapsulated cere b ro s p i n a lfluid collection was identified. The pseudomeningocele wasincised and the defect in the dural closure was seen withthe aid of a Valsalva maneuver (Fig 2). The defect wassealed with suture and muscle with biological glue cover-ing. Continuous CSF drainage was perf o rmed for five days.

Postoperative course – The patient had a good postop-erative re c o v e ry. The lower limbs` strength had a mildi m p rovement immediately. The patient was discharged 4days after the surgery.

At a 6-months re v i e w, the patient’s neurological exam-ination was normal and the postoperative MRI showed re s-olution of the pseudomeningocele (Fig 3).

The patient agreed with the publication of his case.

DISCUSSION

The most common causes of spinal cord compre s-sion are: trauma, neoplasia, degenerative disease,epidural or subdural spinal hematoma, inflammato-ry disease and infection1 0 - 1 7. Postoperative peudo-meningocele is an extremely rare cause of spinal cord

Fig 1. T2-weighted sagittal spinal MRI demonstrates large CSF

collection at T11-T12 levels.

Fig 2. Transoperative photography demonstrates the pseudomeningocele`s cavity and the defect in the dur -

al closure (arrow).

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c o m p re s s i o n6 - 9. A postlaminectomy pseudomeningo-cele was re p o rted first in 1946 by Hyndman and Ger-ber in a review of extradural cysts1 8. In 1947, Swan-son and Fincher1 9 re p o rted the first three cases ofpseudomeningocele after a lumbar discectomy. Wi n-kler and Powers2 0 re p o rted two additional cases ofpseudomeningocele after a lumbar discectomy andt reated both patients with an excision of the menin-gocele and spinal fusion. Myelopathy due to pseudo-meningocele was only re p o rted four times, but in allcases the spinal cord compression was located in thecervical region6-9.

The incidence of a postsurgical pseudomeningo-cele is unknown as many cases probably are asymp-t o m a t i c2 1. Swanson and Fincher1 9 re p o rted a 0.068%incidence of pseudomeningoceles in 1700 explorato-ry laminectomies. Teplick et al.2 noted that 2% of 400laminectomy patients who underwent postoperativeCT scanning had a pseudomeningocele.

The term pseudomeningocele reflects the absenceof a true meningeal layer lining the cyst wall2 1. Thef o rmation of a pseudomeningocele begins with atear in the dura that is closed incompletely or goesunnoticed at the time of a laminectomy. If the arach-noid remains intact, there may be herniation of thearachnoid through the dural opening resulting in anarachnoid-lined cyst2 , 2 0 , 2 2 , 2 3. More commonly, the duraand arachnoid are lacerated, and the CSF pours into

the paraspinal soft tissue. The CSF may be absorbedi n i t i a l l y, but the CSF collection eventually becomesencapsulated by fibrous tissue1,2,24,25.

The optimal selection of diagnostic imaging tech-niques is debated in the literature. CT scanning hasbeen considered in the diagnosis of postoperativepseudomeningocele. Identification of the neck of thepseudomeningocele is improved with the intrathe-cal administration of water-soluble contrast2 , 2 6 , 2 7.Although myelography demonstrates the pseudo-meningocele, the communication between themeningocele sac and the thecal sac usually is not wellvisualized. The use of MRI in the evaluation of post-operative pseudomeningoceles has been re p o rt e dsince 19882 7 , 2 8. MRI studies can provide excellent def-inition of the meningocele and its communicationwith the dural sac. It is considered the g o l d - s t a n d a rdmethod in diagnosing postoperative pseudomeningo-c e l e s2 8. Digital subtraction myelography is also re p o rt-ed in the literature with good results29.

Pseudomeningoceles can be either symptomaticor not. According to Lee et al.2 1, it may be diff i c u l tto determine the real source of symptoms in patientswith a history of local surg e ry and radiological evi-dence of a pseudomeningocele. Tension of the cystagainst the spinal cord or the nerve roots, entrap-ment of nerve roots into the dural defect, or peri-radicular fibrosis can be responsible for the patient’scomplaints21,26.

The treatment of a postoperative pseudomenin-gocele is somewhat controversial. Asymptomaticpseudomeningoceles may be left untreated; howev-e r, it may be difficult to confirm that the pseudo-meningocele is truly asymptomatic. The definitivet reatment of a symptomatic postoperative pseudo-meningocele is surgical and re q u i res adequate expo-s u rein order to localize the dural defect2 6. The durashould be closed primarily, if at all possible. Fibringlue along the suture line may be helpful1 , 2 6. Theremoval of the entire pseudomeningocele sac is un-n e c e s s a ryaccording to the literature2 6. Some authorsrefer other options for the treatment of pseudome-ningoceles, such as peritoneal shunt3 0 and mechani-cal compre s s i o n3 1, but we consider these techniquesas alternative treatments and our pre f e rence is almostalways for the aggressive surgical repair.

Lumbar spinal fluid drainage is a common pro c e-d u re to reduce the risks of CSF fistula after varioustransdural neuro s u rgical pro c e d u re s3 2. Although it isan effective pro c e d u re, some serious complicationsmay ensue. Common adverse events observed with

Fig 3. Postoperative T1-weighted sagittal spinal MRI shows the

resolution of the pseudomeningocele.

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lumbar spinal fluid drainage are infections, pneumo-cephalus, hematoma, and CSF overd r a i n a g e3 2. In thep resent case, we decided to maintain the lumbardrainage for five days, and no complication occurre d .No evidence of treatment failure was observed sixmonths after the procedure.

In conclusion, pseudomeningocele must take partof the diff e rential diagnosis of pro g ressive myelopa-thy after thoracic spine surg e ry. Surgical tre a t m e n tof this entity seems to be effective.

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