Pontine encephalocele and abnormalities of the posterior fossa following transclival endoscopic endonasal surgery

Clinical article

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  • 1 Departments of Neurological Surgery,
  • 2 Otolaryngology, and
  • 3 Radiology, University of Pittsburgh Medical Center; and
  • 4 Department of Epidemiology, University of Pittsburgh, Pennsylvania
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Object

Transclival endoscopic endonasal surgery (EES) has recently been used for the treatment of posterior fossa tumors. The optimal method of reconstruction of large clival defects following EES has not been established.

Methods

A morphometric analysis of the posterior fossa was performed in patients who underwent transclival EES to compare those with observed postoperative anatomical changes (study group) to 50 normal individuals (anatomical control group) and 41 matched transclival cases with preserved posterior fossa anatomy (case-control group) using the same parameters. Given the absence of clival bone following transclival EES, the authors used the line between the anterior commissure and the basion as an equivalent to the clival plane to evaluate the location of the pons. Four parameters were studied and compared in the two populations: the pontine location/displacement, the maximum anteroposterior (AP) diameter of the pons, the maximum AP diameter of the fourth ventricle, and the cervicomedullary angle (CMA). All measurements were performed on midsagittal 3-month postoperative MR images in the study group.

Results

Among 103 posterior fossa tumors treated with transclival EES, 14 cases (13.6%) with postoperative posterior fossa anatomy changes were identified. The most significant change was anterior displacement of the pons (transclival pontine encephalocele) compared with the normal location in the anatomical control group (p < 0.0001). Other significant deformities were expansion of the AP diameter of the pons (p = 0.005), enlargement of the fourth ventricle (p = 0.001), and decrease in the CMA (p < 0.0001). All patients who developed these changes had undergone extensive resection of the clival bone (> 50% of the clivus) and dura. Nine (64.3%) of the 14 patients were overweight (body mass index [BMI] > 25 kg/m2). An association between BMI and the degree of pontine encephalocele was observed, but did not reach statistical significance. The use of a fat graft as part of the reconstruction technique following transclival EES with dural opening was the single significant factor that prevented pontine displacement (p = 0.02), associated with 91% lower odds of pontine encephalocele (OR = 0.09, 95% CI 0.01–0.77). The effect of fat graft reconstruction was more pronounced in overweight/obese individuals (p = 0.04) than in normal-weight patients (p = 0.52). Besides reconstruction technique, other noticeable findings were the tendency of younger adults to develop pontine encephalocele (p = 0.05) and the association of postoperative meningitis with the development of posterior fossa deformities (p = 0.05). One patient developed a transient, recurrent subjective diplopia; all others remained asymptomatic.

Conclusions

Significant changes in posterior fossa anatomy that have potential clinical implications have been observed following transclival transdural EES. These changes are more common in younger patients or those with meningitis and may be associated with BMI. The use of a fat graft combined with the vascularized nasoseptal flap appears to minimize the risk of pontine herniation following transclival EES with dural opening.

Abbreviations used in this paper:AC-B = anterior commissurebasion; AP = anteroposterior; BMI = body mass index; CMA = cervicomedullary angle; EES = endoscopic endonasal surgery; ICP = intracranial pressure; IQR = interquartile range.

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Contributor Notes

Address correspondence to: Paul A. Gardner, M.D., Department of Neurosurgery, UPMC Presbyterian, 200 Lothrop St., Ste. B400, Pittsburgh, PA 15213. email: gardpa@upmc.edu.

Please include this information when citing this paper: published online February 7, 2014; DOI: 10.3171/2013.12.JNS13756.

  • 1

    Acerbi F, , Genden E, & Bederson J: Circumferential watertight dural repair using nitinol U-clips in expanded endonasal and sublabial approaches to the cranial base. Neurosurgery 67:2 Suppl Operative 448456, 2010

    • Search Google Scholar
    • Export Citation
  • 2

    Belliveau MJ, & ten Hove MW: Idiopathic intracranial hypertension. CMAJ 183:1881, 2011

  • 3

    Dlouhy BJ, , Madhavan K, , Clinger JD, , Reddy A, , Dawson JD, & O'Brien EK, : Elevated body mass index and risk of postoperative CSF leak following transsphenoidal surgery. Clinical article. J Neurosurg 116:13111317, 2012

    • Search Google Scholar
    • Export Citation
  • 4

    Friesner D, , Rosenman R, , Lobb BM, & Tanne E: Idiopathic intracranial hypertension in the USA: the role of obesity in establishing prevalence and healthcare costs. Obes Rev 12:e372e380, 2011

    • Search Google Scholar
    • Export Citation
  • 5

    Gardner PA, , Prevedello DM, , Kassam AB, , Snyderman CH, , Carrau RL, & Mintz AH: The evolution of the endonasal approach for craniopharyngiomas. Historical vignette. J Neurosurg 108:10431047, 2008

    • Search Google Scholar
    • Export Citation
  • 6

    Honeybul S: Complications of decompressive craniectomy for head injury. J Clin Neurosci 17:430435, 2010

  • 7

    Honeybul S, & Ho KM: Long-term complications of decompressive craniectomy for head injury. J Neurotrauma 28:929935, 2011

  • 8

    Kelly DF, , Oskouian RJ, & Fineman I: Collagen sponge repair of small cerebrospinal fluid leaks obviates tissue grafts and cerebrospinal fluid diversion after pituitary surgery. Neurosurgery 49:885890, 2001

    • Search Google Scholar
    • Export Citation
  • 9

    Koutourousiou M, , Gardner PA, , Fernandez-Miranda JC, , Paluzzi A, , Wang EW, & Snyderman CH: Endoscopic endonasal surgery for giant pituitary adenomas: advantages and limitations. Clinical article. J Neurosurg 118:621631, 2013

    • Search Google Scholar
    • Export Citation
  • 10

    Koutourousiou M, , Gardner PA, , Tormenti MJ, , Henry SL, , Stefko ST, & Kassam AB, : Endoscopic endonasal approach for resection of cranial base chordomas: outcomes and learning curve. Neurosurgery 71:614625, 2012

    • Search Google Scholar
    • Export Citation
  • 11

    Leng LZ, , Brown S, , Anand VK, & Schwartz TH: “Gasket-seal” watertight closure in minimal-access endoscopic cranial base surgery. Neurosurgery 62:5 Suppl 2 ONSE342ONSE343, 2008

    • Search Google Scholar
    • Export Citation
  • 12

    Nishioka H, , Izawa H, , Ikeda Y, , Namatame H, , Fukami S, & Haraoka J: Dural suturing for repair of cerebrospinal fluid leak in transnasal transsphenoidal surgery. Acta Neurochir (Wien) 151:14271430, 2009

    • Search Google Scholar
    • Export Citation
  • 13

    Shin SS, , Gardner PA, , Stefko ST, , Madhok R, , Fernandez-Miranda JC, & Snyderman CH: Endoscopic endonasal approach for nonvestibular schwannomas. Neurosurgery 69:10461057, 2011

    • Search Google Scholar
    • Export Citation
  • 14

    Stiver SI: Complications of decompressive craniectomy for traumatic brain injury. Neurosurg Focus 26:6 E7, 2009

  • 15

    Wang S, , Wang C, , Passias PG, , Li G, , Yan M, & Zhou H: Interobserver and intraobserver reliability of the cervicomedullary angle in a normal adult population. Eur Spine J 18:13491354, 2009

    • Search Google Scholar
    • Export Citation
  • 16

    Yang XF, , Wen L, , Shen F, , Li G, , Lou R, & Liu WG, : Surgical complications secondary to decompressive craniectomy in patients with a head injury: a series of 108 consecutive cases. Acta Neurochir (Wien) 150:12411248, 2008

    • Search Google Scholar
    • Export Citation
  • 17

    Zanation AM, , Carrau RL, , Snyderman CH, , Germanwala AV, , Gardner PA, & Prevedello DM, : Nasoseptal flap reconstruction of high flow intraoperative cerebral spinal fluid leaks during endoscopic skull base surgery. Am J Rhinol Allergy 23:518521, 2009

    • Search Google Scholar
    • Export Citation

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