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A case of sphenoid sinus meningoencephalocele repaired by an image-guided endoscopic endonasal approach
Auris Nasus Larynx 38 (2011) 632–637 www.elsevier.com/locate/anl
A case of sphenoid sinus meningoencephalocele repaired by an image-guided endoscopic endonasal approach Hiromi Sano a, Yoshinori Matsuwaki a,*, Nobuyoshi Kaito b, Tatsuhiro Joki b, Tetsushi Okushi a, Hiroshi Moriyama a a
Department of Otorhinolaryngology, Jikei University School of Medicine, Tokyo, Japan b Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan Received 1 June 2010; accepted 18 January 2011 Available online 9 March 2011
Abstract We report a Japanese patient with a complaint of unilateral watery nasal discharge. Analysis of the nasal discharge showed it to contain high levels of sugar and transferrin, which indicated cerebrospinal fluid (CSF) rhinorrhea. A diagnosis of sphenoid sinus meningoencephalocele was easily made on the basis of the CT, MRI and nasal discharge findings. We performed surgery by an image-guided endoscopic endonasal approach (IGEEA). An image guidance system (IGS) was used to confirm the position of the bone defect and the prolapsed brain lobe. We resected the brain lobe, and used fat tissue and fascia to create an extracranial–intracranial blockade. As of 18 months after the operation, there is no evidence of infection or CSF leakage. The IGEEA enabled us to successfully repair the middle skull base using a multi-layer sealing technique, while the IGS allowed us to confirm the anatomical structures and successfully avoid causing collateral damage to the surrounding tissues. This case exemplifies the beneficial effect that of the development of surgical support equipment on the operative approach that is now indicated for sphenoid sinus meningoencephaloceles: the endonasal approach has largely replaced other approaches, such as lateral rhinotomy. # 2011 Elsevier Ireland Ltd. All rights reserved. Keywords: Image guidance system; Endoscopic endonasal approach; Meningoencephalocele; Cerebrospinal fluid leakage; Meningitis
1. Introduction Meningoencephalocele is a disease in which the dura mater and the cerebral parenchyma have prolapsed [1]. Most cases consist of a congenital anomaly in which there is protrusion of brain matter to the surface of the head, and in approximately 10% of cases the meningoencephalocele prolapses into the paranasal sinuses [2]. More than half of patients with a meningoencephalocele show prolapse into the ethmoid sinus, whereas sphenoid sinus meningoencephaloceles are rare [3]. Surgery for sphenoid sinus meningoencephaloceles can be performed by a transcranial, lateral rhinotomy, sublabial transseptal (Hardy’s method) or endonasal approaches. For the patient reported here, we * Corresponding author at: 3-25-8 Nishishinbashi, Minato-ku, Tokyo 1058461, Japan. Tel.: +81 3 3433 1111x3601; fax: +81 3 3435 8463. E-mail address: [email protected] (Y. Matsuwaki).
applied an image-guided endoscopic endonasal approach (IGEEA) [4] to successfully repair the middle fossa skull base using a multi-layer sealing technique. The details of this case are presented together with some discussion.
2. Case report Patient: a 53-year-old Japanese male. Chief complaint: unilateral watery nasal discharge. History of the disease: watery nasal discharge from the left nasal cavity started in June 2008, and the patient visited a neighborhood ENT clinic. Anti-allergy drugs were ingested, but there was no improvement. No nasal flow was noted when the patient was in the dorsal position, and it was clear that the flow of the nasal discharge differed by body position. Accordingly, cerebrospinal fluid (CSF) rhinorrhea was suspected, and the patient was referred to our office in
0385-8146/$ – see front matter # 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.anl.2011.01.015
H. Sano et al. / Auris Nasus Larynx 38 (2011) 632–637
the Department of ENT, Jikei University School of Medicine Hospital for further examination on July 24, 2008. Disease history: craniotomy had been performed in 2006 for an occipital meningioma. Initial examination findings: There were no noteworthy intranasal findings or clear findings of body surface anomalies. 2.1. Image findings A paranasal CT scan (Fig. 1, upper) revealed a soft tissue density in the left sphenoid sinus and a bone defect in the lateral aspect of the sphenoid sinus. A T1-weighted, transverse-section cephalic MRI (Fig. 1, lower left) revealed an iso-density area in the left sphenoid sinus that was continuous with the parenchyma and was surrounded by a low-intensity area suggestive of CSF. T2-weighted, coronalsection images (Fig. 1, lower right) revealed an architecture of white matter and gray matter in the left sphenoid sinus that consisted of CSF (white) and continuous brain lobe (gray). 2.2. Examination of the nasal discharge Watery nasal discharge was collected from the left nasal cavity. Analysis revealed it to contain sugar at 65 mg/dl and transferrin at 195 mg/dl, resulting in a diagnosis of CSF rhinorrhea.
633
2.3. Diagnosis and treatment A diagnosis of sphenoid sinus meningoencephalocele was made on the basis of the image and nasal discharge findings. The watery nasal discharge was surmised to be CSF rhinorrhea arising from the meningoencephalocele. One month before coming to our office the patient had experienced a 39 8C fever, and blood sampled at the time of hospitalization indicated a slightly elevated inflammatory response (white blood cell count: 10,800/ml; C-reactive protein: 1.93 mg/dl). Although bacterial culture of the CSF was negative, much continuous CSF leakage to left nasal cavity were observed, when he visited to our hospital. We administered an antibiotic, cefotaxime sodium 2 g/day, which shows good transfer to the CSF, and decided to perform surgery on a semi-emergency basis on August 6, 2008. The operative plan was to first perform IGEEA via the sphenoid sinus. The prolapsed portion of the brain lobe was to be resected, and the middle fossa skull base defect repaired via the sphenoid sinus. In the case of difficulty, wide sphenoidectomy or craniotomy would be performed in cooperation with the Neurosurgery Department. On August 6, 2008, IGEEA was performed under general anesthesia, and the left ethmoid sinus was opened. Then, working via the ethmoid sinus, the anterior wall of the left sphenoid sinus was detached, and a white cystic mass became evident in the sphenoid sinus (Fig. 2, upper left). Resection of the mass resulted in leakage of a clear, colorless
Fig. 1. Preoperative CT and MRI findings for the paranasal sinuses. Arrow shows the bone defect.
634
H. Sano et al. / Auris Nasus Larynx 38 (2011) 632–637
Fig. 2. Endoscopic and image-guided findings during surgery. Upper left: endoscopic finding of brain lobe in the sphenoid sinus. Upper right: image-guided findings show the position of the bone defect and the 708 endoscopic view of the sphenoidal recess. Lower left: endoscopic finding show the fat tissue inserted into the bone defect. Lower right: endoscopic finding of fascia inserted submucosally around the basal portion, which has been detached.
fluid that was assumed to be CSF, and the mass was thus surmised to be the meningoencephalocele that had been diagnosed preoperatively. Next, we confirmed the position of the bone defect and the prolapsed brain lobe using a Kolibri (BrainLAB, Germany) image guidance system (IGS) (Fig. 2, upper right). The diameter of the bone defect was about 9 mm. Because we were able to get a clear view of the sphenoid recess and perform the sealing by using a 708 endoscope, there was no need to perform wide sphenoidectomy or craniotomy. Although it was assumed that the prolapsed brain tissue had lost its function, it was provided with a rich blood supply. Therefore, a bipolar surgical instrument was employed to gradually cauterize and resect the tissue. The base portion was hidden by the mass itself, and thus monopolar cauterization was performed little by little while confirming the base portion with the IGS. After removing the mass, the sinus mucosa around the defect was partially detached. Then fat tissue that had been harvested from the quadriceps femoris in advance was inserted into the bone defect, harvested fascia was inserted submucosally around the basal portion that had been detached, and the communication with the cranium was blocked (Fig. 2, lower left, right). The graft materials were then immobilized using fibrin glue to create a double shield. Finally, in order to
stabilize the immobilized sites temporarily, the left sphenoid sinus was packed with fat and covered with Gelfoam1, and Bethckitin1 impregnated with antibiotics was inserted to immobilize. This completed the operation.
2.4. Postoperative course Postoperatively, the unilateral watery rhinorrhea had disappeared, and the immobilized gauze, Bethckitin1 was partially removed on the 3rd postoperative day and completely removed on the 6th postoperative day. An antibiotic, cefotaxim sodium, was used from prior to the surgery through the 7th postoperative day. The postoperative course was good, with no evidence of infection or CSF leakage. This was partly because we did not perform spinal drainage due to the risk of causing meningitis by suctioning secretion from the sphenoid sinus into the cranial cavity and also because we were able to achieve sufficient sealing during the operation. The patient was released from the hospital on the 15th postoperative day. Pathological examination of the meningoencephalocele revealed brain tissue containing numerous inflammatory cells, mainly lymphocytes (Fig. 3).
H. Sano et al. / Auris Nasus Larynx 38 (2011) 632–637
635
At 18 months after the operation, neither a postoperative CT or MRI (Fig. 4, upper left, right) nor the intranasal findings (Fig. 4, lower left, right) indicated recurrence of the meningoencephalocele or CSF leakage. We also confirmed good aeration of the left sphenoid sinus.
3. Discussion
Fig. 3. Pathological findings for the meningoencephalocele. Resected brain tissue was stained by H-E and observed at high-power magnification (400).
Meningoencephaloceles are classified as occipital, sincipital and basal meningoencephaloceles of the cranial vault or cranioschisis in accordance with the location of the bone defect [5]. The occipital type is the most common, accounting for approximately 70% of all meningoencephaloceles, whereas basal meningoencephaloceles, which are deeply involved in the field of ENT, account for only 10% (a prevalence of one in 35,000–40,000) [1,6]. Based on the site of the bony defect and protrusion, basal meningoencephaloceles are further classified as transethmoidal, sphenoethmoidal, transsphenoidal and frontosphenoidal types [9]. Herniation into the ethmoid sinus accounts for a majority of cases, whereas sphenoid sinus meningoencephaloceles are extremely rare [1]. Only 58 cases of sphenoid sinus meningoencephalocele were previously reported in the
Fig. 4. Postoperative CT, MRI and endoscopic findings after 18 months. Upper left and right: postoperative CT and MRI findings for the paranasal sinuses. Lower left: postoperative endoscopic view from middle nasal meatus. Lower right: postoperative endoscopic view of sphenoidal recess.
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H. Sano et al. / Auris Nasus Larynx 38 (2011) 632–637
Table 1 Stratification of treatment approaches taken for sphenoid meningoencephalocele as function of historical period the data shown in parentheses represent the percentage of total cases in each time period. 1977 I. Transcranial II. Lateral rhinotomy III. Sublabial transseptal IV. Endonasal I + III I + IV Observation Total
1977–1992
1993
Total
8 (57.1) 2 (14.3)
6 (26.1) 0
6 (28.6) 0
20 (34.5) 2 (3.4)
0
4 (17.4)
1 (4.8)
5 (8.6)
0 0 0 4 (28.6) 14
4 1 1 7 23
(17.4) (4.3) (4.3) (30.4)
13 (61.9) 0 0 1 (4.8%) 21
17 1 1 12 58
(29.3) (1.7) (1.7) (20.7)
world, and were summarized in Table 1. Within the basal meningoencephaloceles, transsphenoidal variant accounts for 5% of basal herniations [1]. In addition, meningoencephaloceles can be classified on the basis of their origin: congenital, postoperative, traumatic and idiopathic [6]. The patient we have described had no anomalies or trauma, and although he had previously undergone surgery for an occipital meningioma, the present meningoencephalocele was in a different location. As a result, we surmise that this meningoencephalocele was idiopathic in nature or caused by indirect pressure arising from the previous surgery. Idiopathic meningoencephaloceles are often discovered by accident at the time of detailed examinations performed to determine the cause of CSF leakage or meningitis, or when examining an intranasal mass, etc. Treatment methods for meningoencephaloceles consist of a conservative approach and surgery. The objective of surgery for a sphenoid sinus meningoencephalocele is complete extracranial–intracranial blockade. The surgery can be performed by a transcranial, lateral rhinotomy, sublabial transseptal (Hardy’s method) or endonasal approach [1–15]. In the past, the transcranial approach was considered to provide the broadest field of view, making it easy to repair defects in the dura mater or base of the skull. In fact, for almost all of the early reported cases a transcranial approach was used for surgical repair of sphenoid sinus meningoencephaloceles. However, as a result of the subsequent development and application of endoscopic sinus surgery (ESS) and IGS, there has been a strong trend toward application of the endonasal approach due to its lesser invasiveness. Table 1 presents the historical data on the numbers of surgeries that were performed for sphenoid sinus meningoencephaloceles using the various approaches [1–15]. We compared the data with each surgical approach during three time periods: prior to the widespread use of ESS (1977), after the widespread use of ESS (1978) and after the widespread use of IGS (1993). The transcranial approach is still used for child patients today, and for that reason there has not been any great change in the percentage of patients treated by that approach over the years. However, prior to 1977, there had been absolutely no
opportunity to select the endonasal approach. In contrast, at present (1993), with further development of the IGS, the endonasal approach is much more frequently selected and is now employed for 61.9% of cases of sphenoid sinus meningoencephalocele. But most of the cases, which were reported previously, operations were high invasive even if the endonasal approach was selected. For example, opening all sinuses bilaterally and resecting upper and middle turbinate and the posterior part of nasal septum, such as wide sphenoidectomy. In the case described here, we approached unilaterally via middle nasal meatus to the sphenoid sinus by using 708 endoscopy with IGS and preserved upper, middle and inferior turbinates. Although ESS and IGS are nowadays popular surgical method, we were able to perform with less invasion compared to the previous reported cases by combining these two procedures. We think that the development and popularization of IGS has directly expanded the indication for the endonasal approach, because it can intuitively show the surgical anatomy. Coupled with that trend, there has been a decrease in patients who are merely observed. The indications for IGS for ESS (IGESS) recommended by the AAO (American Academy of Otolaryngology) include lesions that are contiguous with the optic nerve or the internal carotid artery running in the vicinity of the sphenoid sinus, CSF rhinorrhea and skull base defects. IGESS is extremely useful for operation on sphenoid sinus meningoencephaloceles, and that can be surmised to be the reason that selection of the endonasal approach has become more frequent. Nevertheless, the endonasal approach cannot be indicated for all patients. For example, when the field of view is narrow, making it difficult to perform the necessary manipulations, or when the defective site is large and the manipulations would be difficult by the endonasal approach, it can be thought that other approaches should be considered. In the patient that we have described here, combined application of the endonasal approach and an IGS allowed us to confirm the anatomical positions and directions at all times, and successfully reconstruct the skull base without causing collateral damage to the internal carotid artery, optic nerve, vidian nerve, maxillary nerve and other surrounding tissues.
Conflict of interest None.
References [1] Formica F, Iammelli A, Paludetti G, Di Rocco C. Transsphenoidal meningoencephalocele. Childs Nerv Syst 2002;18:295–8. [2] Kai Y, Nagahiro S, Yoshioka S, Ushino Y. Application of the skull base technique to the repair of transsphenoidal meningoencephaloceles. Pediatr Neurosurg 1996;25:54–6.
H. Sano et al. / Auris Nasus Larynx 38 (2011) 632–637 [3] Myssiorek D, Cohen N. Intrasphenoidal meningoencephalocele: a case report. Am J Otolaryngol 1987;8:391–4. [4] Lam S, Huang C, Newman J, Anand V. Computer-aided image-guided endoscopic sinus surgery in unusual cases of sphenoid disease. Rhinology 2002;40:179–84. [5] Suwanwela C, Suwanwela N. A morphologic classification of sincipital encephalomeningoceles. J Neurosurg 1972;30:201–11. [6] Blaivie C, Lequeux T, Kampouridis S, Louryan S, Saussez S. Congenital transsphenoidal meningocele: case report and review of the literature. Am J Otolaryngol 2006;27:422–4. [7] Kobayashi S. A case of transsphenoidal meningoencephalocele. Neurol Surg 1998;11:1065–70. [8] Albernaz M, Horton W, Adkins W, Garen P. Intrasphenoidal encephalocele. Otolaryngol Head Neck Surg 1991;104:279–81. [9] Buchfelder M, Fahlbusch R, Huk W, Thierauf P. Intrasphenoidal encephaloceles—a clinical entity. Acta Neurochir (Wien) 1987;89: 10–5.
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[10] Gibson W. Sphenoid sinus revisited. Laryngoscope 1984;94:185–91. [11] Kaufman B, Yonas H, White R, Miller C. Acquired middle cranial fossa fistulas: normal pressure and nontraumatic in origin. Neurosurgery 1979;5:466–72. [12] Schick B, Brors D, Prescher A. Sternberg’s canal—cause of congenital sphenoidal meningocele. Eur Arch Otorhinolaryngol 2000;257:430–2. [13] Laedrach K, Remonda L, Lukes A, Schroth G, Reveh J. Evaluation of the contribution of CAS in combination with the subcranial/subfrontal approach in anterior skull base surgery. Skull Base 2001;11:59–76. [14] Socher J, Cassano M, Filheiro C, Cassano P, Felippu A. Diagnosis and treatment of isolated sphenoid sinus disease: a review of 109 cases. Acta Otolaryngol 2008;128:1004–10. [15] Cappabianca P, Cavallo LM, Esposito F, De Divitiis O, Messina A, De Divitiis E. Extended endoscopic endonasal approach to the midline skull base: the evolving role of transsphenoidal surgery. Adv Tech Stand Neurosurg 2008;151–99.
A case of sphenoid sinus meningoencephalocele repaired by an image-guided endoscopic endonasal approach Hiromi Sano a, Yoshinori Matsuwaki a,*, Nobuyoshi Kaito b, Tatsuhiro Joki b, Tetsushi Okushi a, Hiroshi Moriyama a a
Department of Otorhinolaryngology, Jikei University School of Medicine, Tokyo, Japan b Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan Received 1 June 2010; accepted 18 January 2011 Available online 9 March 2011
Abstract We report a Japanese patient with a complaint of unilateral watery nasal discharge. Analysis of the nasal discharge showed it to contain high levels of sugar and transferrin, which indicated cerebrospinal fluid (CSF) rhinorrhea. A diagnosis of sphenoid sinus meningoencephalocele was easily made on the basis of the CT, MRI and nasal discharge findings. We performed surgery by an image-guided endoscopic endonasal approach (IGEEA). An image guidance system (IGS) was used to confirm the position of the bone defect and the prolapsed brain lobe. We resected the brain lobe, and used fat tissue and fascia to create an extracranial–intracranial blockade. As of 18 months after the operation, there is no evidence of infection or CSF leakage. The IGEEA enabled us to successfully repair the middle skull base using a multi-layer sealing technique, while the IGS allowed us to confirm the anatomical structures and successfully avoid causing collateral damage to the surrounding tissues. This case exemplifies the beneficial effect that of the development of surgical support equipment on the operative approach that is now indicated for sphenoid sinus meningoencephaloceles: the endonasal approach has largely replaced other approaches, such as lateral rhinotomy. # 2011 Elsevier Ireland Ltd. All rights reserved. Keywords: Image guidance system; Endoscopic endonasal approach; Meningoencephalocele; Cerebrospinal fluid leakage; Meningitis
1. Introduction Meningoencephalocele is a disease in which the dura mater and the cerebral parenchyma have prolapsed [1]. Most cases consist of a congenital anomaly in which there is protrusion of brain matter to the surface of the head, and in approximately 10% of cases the meningoencephalocele prolapses into the paranasal sinuses [2]. More than half of patients with a meningoencephalocele show prolapse into the ethmoid sinus, whereas sphenoid sinus meningoencephaloceles are rare [3]. Surgery for sphenoid sinus meningoencephaloceles can be performed by a transcranial, lateral rhinotomy, sublabial transseptal (Hardy’s method) or endonasal approaches. For the patient reported here, we * Corresponding author at: 3-25-8 Nishishinbashi, Minato-ku, Tokyo 1058461, Japan. Tel.: +81 3 3433 1111x3601; fax: +81 3 3435 8463. E-mail address: [email protected] (Y. Matsuwaki).
applied an image-guided endoscopic endonasal approach (IGEEA) [4] to successfully repair the middle fossa skull base using a multi-layer sealing technique. The details of this case are presented together with some discussion.
2. Case report Patient: a 53-year-old Japanese male. Chief complaint: unilateral watery nasal discharge. History of the disease: watery nasal discharge from the left nasal cavity started in June 2008, and the patient visited a neighborhood ENT clinic. Anti-allergy drugs were ingested, but there was no improvement. No nasal flow was noted when the patient was in the dorsal position, and it was clear that the flow of the nasal discharge differed by body position. Accordingly, cerebrospinal fluid (CSF) rhinorrhea was suspected, and the patient was referred to our office in
0385-8146/$ – see front matter # 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.anl.2011.01.015
H. Sano et al. / Auris Nasus Larynx 38 (2011) 632–637
the Department of ENT, Jikei University School of Medicine Hospital for further examination on July 24, 2008. Disease history: craniotomy had been performed in 2006 for an occipital meningioma. Initial examination findings: There were no noteworthy intranasal findings or clear findings of body surface anomalies. 2.1. Image findings A paranasal CT scan (Fig. 1, upper) revealed a soft tissue density in the left sphenoid sinus and a bone defect in the lateral aspect of the sphenoid sinus. A T1-weighted, transverse-section cephalic MRI (Fig. 1, lower left) revealed an iso-density area in the left sphenoid sinus that was continuous with the parenchyma and was surrounded by a low-intensity area suggestive of CSF. T2-weighted, coronalsection images (Fig. 1, lower right) revealed an architecture of white matter and gray matter in the left sphenoid sinus that consisted of CSF (white) and continuous brain lobe (gray). 2.2. Examination of the nasal discharge Watery nasal discharge was collected from the left nasal cavity. Analysis revealed it to contain sugar at 65 mg/dl and transferrin at 195 mg/dl, resulting in a diagnosis of CSF rhinorrhea.
633
2.3. Diagnosis and treatment A diagnosis of sphenoid sinus meningoencephalocele was made on the basis of the image and nasal discharge findings. The watery nasal discharge was surmised to be CSF rhinorrhea arising from the meningoencephalocele. One month before coming to our office the patient had experienced a 39 8C fever, and blood sampled at the time of hospitalization indicated a slightly elevated inflammatory response (white blood cell count: 10,800/ml; C-reactive protein: 1.93 mg/dl). Although bacterial culture of the CSF was negative, much continuous CSF leakage to left nasal cavity were observed, when he visited to our hospital. We administered an antibiotic, cefotaxime sodium 2 g/day, which shows good transfer to the CSF, and decided to perform surgery on a semi-emergency basis on August 6, 2008. The operative plan was to first perform IGEEA via the sphenoid sinus. The prolapsed portion of the brain lobe was to be resected, and the middle fossa skull base defect repaired via the sphenoid sinus. In the case of difficulty, wide sphenoidectomy or craniotomy would be performed in cooperation with the Neurosurgery Department. On August 6, 2008, IGEEA was performed under general anesthesia, and the left ethmoid sinus was opened. Then, working via the ethmoid sinus, the anterior wall of the left sphenoid sinus was detached, and a white cystic mass became evident in the sphenoid sinus (Fig. 2, upper left). Resection of the mass resulted in leakage of a clear, colorless
Fig. 1. Preoperative CT and MRI findings for the paranasal sinuses. Arrow shows the bone defect.
634
H. Sano et al. / Auris Nasus Larynx 38 (2011) 632–637
Fig. 2. Endoscopic and image-guided findings during surgery. Upper left: endoscopic finding of brain lobe in the sphenoid sinus. Upper right: image-guided findings show the position of the bone defect and the 708 endoscopic view of the sphenoidal recess. Lower left: endoscopic finding show the fat tissue inserted into the bone defect. Lower right: endoscopic finding of fascia inserted submucosally around the basal portion, which has been detached.
fluid that was assumed to be CSF, and the mass was thus surmised to be the meningoencephalocele that had been diagnosed preoperatively. Next, we confirmed the position of the bone defect and the prolapsed brain lobe using a Kolibri (BrainLAB, Germany) image guidance system (IGS) (Fig. 2, upper right). The diameter of the bone defect was about 9 mm. Because we were able to get a clear view of the sphenoid recess and perform the sealing by using a 708 endoscope, there was no need to perform wide sphenoidectomy or craniotomy. Although it was assumed that the prolapsed brain tissue had lost its function, it was provided with a rich blood supply. Therefore, a bipolar surgical instrument was employed to gradually cauterize and resect the tissue. The base portion was hidden by the mass itself, and thus monopolar cauterization was performed little by little while confirming the base portion with the IGS. After removing the mass, the sinus mucosa around the defect was partially detached. Then fat tissue that had been harvested from the quadriceps femoris in advance was inserted into the bone defect, harvested fascia was inserted submucosally around the basal portion that had been detached, and the communication with the cranium was blocked (Fig. 2, lower left, right). The graft materials were then immobilized using fibrin glue to create a double shield. Finally, in order to
stabilize the immobilized sites temporarily, the left sphenoid sinus was packed with fat and covered with Gelfoam1, and Bethckitin1 impregnated with antibiotics was inserted to immobilize. This completed the operation.
2.4. Postoperative course Postoperatively, the unilateral watery rhinorrhea had disappeared, and the immobilized gauze, Bethckitin1 was partially removed on the 3rd postoperative day and completely removed on the 6th postoperative day. An antibiotic, cefotaxim sodium, was used from prior to the surgery through the 7th postoperative day. The postoperative course was good, with no evidence of infection or CSF leakage. This was partly because we did not perform spinal drainage due to the risk of causing meningitis by suctioning secretion from the sphenoid sinus into the cranial cavity and also because we were able to achieve sufficient sealing during the operation. The patient was released from the hospital on the 15th postoperative day. Pathological examination of the meningoencephalocele revealed brain tissue containing numerous inflammatory cells, mainly lymphocytes (Fig. 3).
H. Sano et al. / Auris Nasus Larynx 38 (2011) 632–637
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At 18 months after the operation, neither a postoperative CT or MRI (Fig. 4, upper left, right) nor the intranasal findings (Fig. 4, lower left, right) indicated recurrence of the meningoencephalocele or CSF leakage. We also confirmed good aeration of the left sphenoid sinus.
3. Discussion
Fig. 3. Pathological findings for the meningoencephalocele. Resected brain tissue was stained by H-E and observed at high-power magnification (400).
Meningoencephaloceles are classified as occipital, sincipital and basal meningoencephaloceles of the cranial vault or cranioschisis in accordance with the location of the bone defect [5]. The occipital type is the most common, accounting for approximately 70% of all meningoencephaloceles, whereas basal meningoencephaloceles, which are deeply involved in the field of ENT, account for only 10% (a prevalence of one in 35,000–40,000) [1,6]. Based on the site of the bony defect and protrusion, basal meningoencephaloceles are further classified as transethmoidal, sphenoethmoidal, transsphenoidal and frontosphenoidal types [9]. Herniation into the ethmoid sinus accounts for a majority of cases, whereas sphenoid sinus meningoencephaloceles are extremely rare [1]. Only 58 cases of sphenoid sinus meningoencephalocele were previously reported in the
Fig. 4. Postoperative CT, MRI and endoscopic findings after 18 months. Upper left and right: postoperative CT and MRI findings for the paranasal sinuses. Lower left: postoperative endoscopic view from middle nasal meatus. Lower right: postoperative endoscopic view of sphenoidal recess.
636
H. Sano et al. / Auris Nasus Larynx 38 (2011) 632–637
Table 1 Stratification of treatment approaches taken for sphenoid meningoencephalocele as function of historical period the data shown in parentheses represent the percentage of total cases in each time period. 1977 I. Transcranial II. Lateral rhinotomy III. Sublabial transseptal IV. Endonasal I + III I + IV Observation Total
1977–1992
1993
Total
8 (57.1) 2 (14.3)
6 (26.1) 0
6 (28.6) 0
20 (34.5) 2 (3.4)
0
4 (17.4)
1 (4.8)
5 (8.6)
0 0 0 4 (28.6) 14
4 1 1 7 23
(17.4) (4.3) (4.3) (30.4)
13 (61.9) 0 0 1 (4.8%) 21
17 1 1 12 58
(29.3) (1.7) (1.7) (20.7)
world, and were summarized in Table 1. Within the basal meningoencephaloceles, transsphenoidal variant accounts for 5% of basal herniations [1]. In addition, meningoencephaloceles can be classified on the basis of their origin: congenital, postoperative, traumatic and idiopathic [6]. The patient we have described had no anomalies or trauma, and although he had previously undergone surgery for an occipital meningioma, the present meningoencephalocele was in a different location. As a result, we surmise that this meningoencephalocele was idiopathic in nature or caused by indirect pressure arising from the previous surgery. Idiopathic meningoencephaloceles are often discovered by accident at the time of detailed examinations performed to determine the cause of CSF leakage or meningitis, or when examining an intranasal mass, etc. Treatment methods for meningoencephaloceles consist of a conservative approach and surgery. The objective of surgery for a sphenoid sinus meningoencephalocele is complete extracranial–intracranial blockade. The surgery can be performed by a transcranial, lateral rhinotomy, sublabial transseptal (Hardy’s method) or endonasal approach [1–15]. In the past, the transcranial approach was considered to provide the broadest field of view, making it easy to repair defects in the dura mater or base of the skull. In fact, for almost all of the early reported cases a transcranial approach was used for surgical repair of sphenoid sinus meningoencephaloceles. However, as a result of the subsequent development and application of endoscopic sinus surgery (ESS) and IGS, there has been a strong trend toward application of the endonasal approach due to its lesser invasiveness. Table 1 presents the historical data on the numbers of surgeries that were performed for sphenoid sinus meningoencephaloceles using the various approaches [1–15]. We compared the data with each surgical approach during three time periods: prior to the widespread use of ESS (1977), after the widespread use of ESS (1978) and after the widespread use of IGS (1993). The transcranial approach is still used for child patients today, and for that reason there has not been any great change in the percentage of patients treated by that approach over the years. However, prior to 1977, there had been absolutely no
opportunity to select the endonasal approach. In contrast, at present (1993), with further development of the IGS, the endonasal approach is much more frequently selected and is now employed for 61.9% of cases of sphenoid sinus meningoencephalocele. But most of the cases, which were reported previously, operations were high invasive even if the endonasal approach was selected. For example, opening all sinuses bilaterally and resecting upper and middle turbinate and the posterior part of nasal septum, such as wide sphenoidectomy. In the case described here, we approached unilaterally via middle nasal meatus to the sphenoid sinus by using 708 endoscopy with IGS and preserved upper, middle and inferior turbinates. Although ESS and IGS are nowadays popular surgical method, we were able to perform with less invasion compared to the previous reported cases by combining these two procedures. We think that the development and popularization of IGS has directly expanded the indication for the endonasal approach, because it can intuitively show the surgical anatomy. Coupled with that trend, there has been a decrease in patients who are merely observed. The indications for IGS for ESS (IGESS) recommended by the AAO (American Academy of Otolaryngology) include lesions that are contiguous with the optic nerve or the internal carotid artery running in the vicinity of the sphenoid sinus, CSF rhinorrhea and skull base defects. IGESS is extremely useful for operation on sphenoid sinus meningoencephaloceles, and that can be surmised to be the reason that selection of the endonasal approach has become more frequent. Nevertheless, the endonasal approach cannot be indicated for all patients. For example, when the field of view is narrow, making it difficult to perform the necessary manipulations, or when the defective site is large and the manipulations would be difficult by the endonasal approach, it can be thought that other approaches should be considered. In the patient that we have described here, combined application of the endonasal approach and an IGS allowed us to confirm the anatomical positions and directions at all times, and successfully reconstruct the skull base without causing collateral damage to the internal carotid artery, optic nerve, vidian nerve, maxillary nerve and other surrounding tissues.
Conflict of interest None.
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