Childs Nerv Syst DOI 10.1007/s00381-015-2746-y
ORIGINAL PAPER
Endoscopic transnasal repair of cerebrospinal fluid leaks with and without an encephalocele in pediatric patients: from infants to children Jingying Ma 1 & Qian Huang 1 & Xiaokui Li 2 & Dongsheng Huang 3 & Junfang Xian 4 & Shunjiu Cui 1 & Yunchuan Li 1 & Bing Zhou 1
Received: 19 February 2015 / Accepted: 5 May 2015 # Springer-Verlag Berlin Heidelberg 2015
Abstract Purpose The diagnosis and management of pediatric cerebrospinal fluid (CSF) leak and encephalocele are challenging. The current study aimed to identify patient characteristics, review operative techniques, and evaluate the efficacy and safety of endoscopic endonasal repair in a pediatric population. Methods We retrospectively reviewed the records of pediatric patients who underwent transnasal endoscopic repair of CSF leak with or without a meningocele or an encephalocele at Beijing Tongren Hospital, Capital Medical University, between July 2003 and May 2014. All patients had preoperative radiological evaluations and underwent endoscopic endonasal repair of their skull base defects. Results Altogether, 23 children (mean age 7.0 years) underwent the procedures. Sixteen cases were congenital, and 7 patients had trauma history. The herniations or defects included meningoencephaloceles in 15 cases, meningoceles in 4 cases, and CSF leak in 4 cases (2 patients had bilateral leaks). The leak or herniation sites were ethmoid roof in 10 patients (one was bilateral), cribriform plate in 5, lateral to the
* Bing Zhou [email protected] 1
Department of Otolaryngology–Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, 1 Dongjiaominxiang Lane, Dongcheng District, Beijing 100730, China
2
Department of Anesthesiology, Beijing New Century Women’s and Children’s Hospital, Beijing, China
3
Department of Pediatrics, Beijing Tongren Hospital, Capital Medical University, Beijing, China
4
Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
foramen cecum in 3, posterior wall of the frontal sinus in 1, sphenoid sinus in 2, lateral recess of the sphenoid sinus in 1, and sella turcica base in 2. All subjects had favorable clinical outcomes without recurrence during a follow-up of 6– 123 months (mean 61.1 months). Conclusions The endoscopic endonasal approach was the preferred method for repairing CSF leaks with or without an encephalocele in pediatric patients. Compared to traditional operations, this endoscopic procedure is minimally invasive, efficient, and safe. Keywords Cerebrospinal fluid leak . Endoscopy . Encephalocele . Pediatric
Introduction Skull base defects are rarely identified in children. Causes of these defects include accidental trauma and iatrogenic trauma. They may also appear spontaneously or be congenital. Previous reports have shown that the incidence of congenital cerebrospinal fluid (CSF) leak with anterior basal encephalocele is approximately one in 4000–5000 live births [3, 15]. Congenital encephalocele is an open neural tube defect that allows herniation of the meninges and brain matter through a structural defect in the cranium [9]. Although these congenital defects are present at birth, it is likely that they are not diagnosed until the patient has symptoms of a CSF leak, meningitis, a facial deformity, or nasal obstruction. Over the past century, there have been many advances in surgical approaches to repairing skull base defects. As severe complications have been frequently reported following intracranial procedures, the focus has moved to extracranial approaches, including external ethmoidectomy and a transnasal approach. In 1989, Papay et al. reported clinical application of
Childs Nerv Syst
transnasal endoscopic CSF rhinorrhea repair [11]. The transnasal endoscopic approach has now been widely used in adults and has become the first-line treatment for repairing their anterior skull base defects. The general principles and results of endoscopic transnasal surgery in adults, however, cannot be directly extrapolated to infants and children. Thus, to date, this approach has not been evaluated in the pediatric population. The aim of the current study was to extend clinical experience with this procedure to pediatric patients and evaluate the effectiveness of endoscopic endonasal repair for CSF leak with or without the presence of encephalocele in that population.
Materials and methods From July 2003 to May 2014, a total of 23 pediatric patients (15 male, 8 female) underwent transnasal endoscopic repair for CSF leaks, meningoceles, and encephaloceles in the Department of Otolaryngology–Head and Neck Surgery of Beijing Tongren Hospital, Capital Medical University. Two patients underwent a bilateral operation. Patients’ ages ranged from 3 months to 14.0 years (mean 7.0 years). Formal consent is not required for this type of study. Preoperative preparation We reviewed the symptoms and signs, duration of symptoms at diagnosis, skull base defect localizations, causes, management, graft materials, recurrences, and complications. The infants underwent physical examination through a 2.7-mm endoscope and others throughout a 4.0-mm endoscope. All patients underwent computed tomography (CT) of the sinuses with a 2-mm slice bony window. When a mass in the nasal cavity was suspected, magnetic resonance (MR) images were obtained for a differential diagnosis. In cases of rhinorrhea, MRI cisternography (MRC) was undertaken to localize the leakage site. Operative procedures All defects were repaired using the endoscopic transnasal approach for skull base defects with 4.0- or 2.7-mm rigid endoscopes and microinstruments. Surgery was performed under general anesthesia, which was given intravenously in combination with inhaled anesthesia. Mucosal shrinking to minimize bleeding was induced by applying cotton strips soaked in tetracaine with 1:100,000 epinephrine solution. The first step of the surgery was to adequately expose the entire defect. The surgical approach varied depending on the site and size of the defect identified by preoperative imaging. Routine ethmoidectomy was performed for defects in the ethmoid roof or cribriform plate. A Draf III procedure [16] was
performed for defects in the frontal sinus. Defects in the central sphenoid regions were approached via direct sphenoidotomy or transethmoidally. A transpterygoid approach [17] was used to access the sphenoid sinus for defects in the lateral recess of the sphenoid. Following defect exposure, bipolar cautery was used to coagulate and resect meningoceles and encephaloceles. When dissecting tight adhesions between the mucosa and bone, the mucosa was dissected about 5 mm around the leak site, and careful bipolar cautery coagulation was applied. A variety of soft tissue materials—temporalis fascia, free mucosal grafts from middle turbinates, vascularized nasoseptal [6] or middle turbinate [12] flaps—were used for underlay or overlay grafts. For rigid grafting, we used bone grafts from the nasal septum or middle turbinate. Finally, we placed absorbable packing material (e.g., Gelfoam) and/or iodoform gauze underneath the graft for 2–3 weeks. Postoperative care and follow-up All patients received intravenous antibiotic prophylaxis (thirdgeneration cephalosporin) postoperatively. Endoscopic cleanup included removing the iodoform gauze under general anesthesia within 3 weeks after the surgery. The patients were then evaluated endoscopically every 2–4 weeks until epithelialization of the mucous membrane was apparent and thereafter once a year. CT examination was performed in all patients 12– 24 months after the surgery.
Results In all, 16 (69.6 %) of the defects were congenital, and 7 (30.4 %) had been caused by trauma. Among the 23 children, 12 had a major symptom of CSF rhinorrhea, 6 had a history of meningitis, 2 had recurrent pneumonia, and 12 complained of nasal obstruction. It should be noted that nine infants less than 1 year of age were identified by their symptoms of nasal obstruction, including mouth breathing and feeding difficulties. In 14 patients, nasal endoscopy found, upon the patients’ crying, a unilateral polypoid mass with enlargement in the nasal cavity. The clinical characteristics, including age, cause, symptom, type of herniation, and location, among other items of interest are shown in Table 1. CT clearly revealed skull base fractures or defects in 22 cases (Fig. 1a). Unilateral soft tissue shadows in the sinus with skull base defects were found in 14 patients (by CT in 7 cases, by CT and MRI for 7 cases) (Fig. 2a–c). MRC revealed lineshaped high-signal connections between high-signal intracranial CSF and high-signal CSF in the nasal cavity in 8 patients. The exact location of the CSF leak was detectable by CT or MRI in all but one patient, in whom it was identified during surgical exploration.
Childs Nerv Syst Table 1
Clinical characteristics of 23 patients with skull base defects
Age
Symptoms
Type of herniation
Location
Defect size (mm2)
Graft
4 months 6 years 10 years 4 months
Nasal obstruction Nasal obstruction Meningitis Nasal obstruction
ME ME M ME
Cribriform plate Base of sella turcica Ethmoid roof Ethmoid roof
4 150 16 4
TF PNSF+fascia lata UPM TF
12 months 14 years 13 years 13 years 12 months 16 months 8 years 11 years 11 months 12 years
Nasal obstruction, rhinorrea, meningitis Nasal obstruction Rhinorrea Nasal obstruction, rhinorrea Nasal obstruction Rhinorrea Meningitis Rhinorrea Nasal obstruction, rhinorrea, pneumonia Nasal obstruction, rhinorrea
ME ME None ME ME ME ME M ME None
3 months 10 years 12 years 13 years 7 months 11 years 5 months
Nasal obstruction Rhinorrea Rhinorrea, meningitis Rhinorrea, meningitis Nasal obstruction Meningitis Nasal obstruction
ME None M ME ME None ME
Ethmoid roof Cribriform plate (Bilateral) ethmoid roof Ethmoid roof Cribriform plate Ethmoid roof Ethmoid roof Ethmoid roof Cribriform plate (Right) ethmoid roof (Left) lateral wall of sphenoid Cribriform plate Posterior wall of frontal sinus Lateral recess of sphenoid Cribriform plate Cribriform plate Cribriform plate Base of sella turcica
150 50 4 18 None 9 144 120 45 25 4 None 25 4 64 None 6 None
Artificial bone+PNSF MTB+PNSF (Bilateral) MTM MTB+PNSF None MTB+TF MTB+TF MTB+PNSF PMTF (Right) PSTF (Left) PSTF None TF TF MTB+MTM None PMTF None
5 months 13 years
Nasal obstruction, rhinorrhea, pneumonia Rhinorrea
ME None
Ethmoid roof Lateral wall of sphenoid
70 4
PNSF MTM
ME Meningo-encephalocele, M Meningocele, TF temporalis fascia, UPM mucosa of uncinate process, PNSF Pedicled nasoseptal flap, PMTF Pedicled middle turbinate flap, PSTF Pedicled superior turbinate flap, NSB nasoseptal bone, MTB middle turbinate bone, MTM middle turbinate mucosa
The herniations were identified as meningoencephaloceles in 15 cases, meningoceles in 3 patients, and CSF leaks in 5 patients (2 patients had bilateral leaks). The leak sites were successfully located in the ethmoid roof in 10 patients (1 case was bilateral), cribriform plate in 5, posterior wall of the
frontal sinus in 1, sphenoid sinus in 2 (the leak on the other side was in the ethmoid roof), lateral recess of the sphenoid sinus in 1, and base of the sella turcica in 2. In the other three patients, encephaloceles were located lateral to the foramen cecum and anterior to the cribriform plate. The defect in the
Fig. 1 Ten-year-old patient with traumatic cerebrospinal fluid (CSF) leak at the posterior wall of the frontal sinus. An improved Draf III procedure was performed to reveal the leak location, which was repaired with temporalis fascia. At the 24-month follow-up, the patient was doing well without further seizures, infection, or CSF leak. a Coronal computed
tomography (CT) shows a skull base defect (white arrow). b Defect in the posterior wall of the right frontal sinus shown by the Draf III approach (white arrow). c Postoperative CT scan shows that the defect had been repaired (white arrow)
Childs Nerv Syst Fig. 2 Coronal (a) and sagittal (b) CT scans demonstrate a large intranasal mass with an associated anterior skull base defect (white arrow). c MRI shows that a meningoencephalocele is clearly visible in the left nasal fossa (white arrow)
posterior wall of the frontal sinus was repaired using a Draf III procedure (Fig. 1b, c), and the defect in the sphenoid lateral recess was repaired via transpterygoid intervention. The others underwent routine endoscopic sinus operations. The defects measured 4–150 mm2. In four patients, no defect was found after removal of a nasal mass. Pathologic assessment of these masses identified them as brain tissue, so no further repair was necessary. The soft reconstructive materials for 13 defects in 11 patients consisted of temporalis fascia (n=4), free mucosal grafts from the uncinate process (n=2) and middle turbinate (n=2), a vascularized nasoseptal flap (n=3, one with fascia lata), and a vascularized middle turbinate flap (n=4). For the other seven relatively larger skull base defects, we used a multilayer repair technique that consisted of combined soft tissue graft and rigid graft, including nasoseptal bone with a vascularized nasoseptal flap (n=3), middle turbinate bone with temporalis fascia (n=2), middle turbinate bone with mucosa (n=1), and artificial bone with a vascularized nasoseptal flap (n=1). The mean duration of the operation was 134 min (range 60–240 min). The mean amount of bleeding was 20.0 ml (range 5–50 ml). None of our patients developed any intraoperative or postoperative complications or required further revision surgery. We had a 100 % success rate with a mean follow-up of 61.1 months (range 6–123 months).
Discussion
dehiscence in the skull base and provide important bony details to help choose the surgical approach. In contrast, MRI is able to clearly distinguish brain parenchyma and CSF that have herniated into the sinus. Efficacy and safety of endoscopic repair Surgical repair of skull base defects is performed to prevent meningitis, intracranial abscess, and the growth’s influence on nasal obstruction, oral breathing, and feeding difficulties. Traditionally, these defects have been managed via craniotomy or lateral rhinotomy. A number of studies have reported a 40 % recurrence rate with these approaches, however, and significant morbidity including anosmia, memory deficits, loss of smell, and intracranial hemorrhage [1]. In the past, timing of the repair focused on allowing adequate time for growth to avoid those complications. Since the early 1980s, however, the transnasal endoscopic approach has progressively become the first-line treatment for repairing anterior skull base defects in adults, with success rates up to 90 % [16]. These results, however, cannot be simply applied to pediatric patients whose nasal cavities are narrow. Our study shows that endoscopic endonasal repair of skull base defects is a safe and efficient approach in pediatric patients, which is in line with prior reports [7, 8]. Importantly, all of our patients had a quick recovery without complications. Also, there is no age limit for endoscopic endonasal surgery. Notably, the youngest reported patient was 1.5 months [5]. The youngest patient in our study was 3 months, and nine children were younger than 1 year of age.
Clinical feature and diagnosis Special considerations for pediatric patients A pediatric skull base defect is rare and challenging in regard to diagnosis and management. Nasal encephaloceles are sometimes asymptomatic, whereas others manifest as nasal obstruction, oral breathing, and headache. Others are associated with CSF rhinorrhea or, rarely, meningitis. The defect may present at birth as a mass in the nose causing upper airway obstruction [14]. Nasal obstruction was observed in 12 of our 23 patients, including nine infants less than 1 year of age. Therefore, encephalocele should be suspected when a child presents with a unilateral nasal mass. It can be confirmed by endoscopy and/or radiologic imaging. CT may locate
The endoscopic endonasal technique still has some indications. Experience in the management of intracranial pathologies of otolaryngologists is an important premise. Minimizing the potential serious risk of pneumonia, meningitis, and other intracranial complications is paramount in the decision making process. The choice of timing for the surgery should be discussed. Among our patients, two had rhinorrhea and recurrent pneumonia. We chose a Btime window^ during which to perform their operations based on when their temperatures returned to normal after antibiotic treatment by their pediatricians. After surgery,
Childs Nerv Syst
neither patient had a recurrence of pneumonia, presumably because rhinorrheal stimulation was no longer present. The endoscopic procedure is technically difficult in pediatric patients because of their narrow nasal cavities. Thin, rigid endoscopes (external diameter 2.7 mm) and some microinstruments can be applied and are helpful. It may be difficult to maintain fluid balance in pediatric patients, particularly in those with mannitol therapy or blood loss. As suggested by Abdel-Aziz et al. [2], oversedation of infants should be avoided as it may result in decreased respiratory effort and increased intracranial pressure secondary to hypercarbia. Careful surgery and application of electric coagulation and cotton strips soaked in epinephrine can reduce bleeding. The use of minor cotton strips also could protect the mucosa. Cooperation between experienced surgeons and anesthetists is thus critical for obtaining the best clinical outcomes. Endoscopic operative approach The appropriate surgical approach varies depending on the exact site and size of the defect, equipment availability, and the experience of the surgeon. Lesions in the ethmoid roof and on the cribriform plate are not difficult to manage with ethmoidectomy. In three infants of our study, the roots of brain tissue were found lateral to the foramen cecum, anterior to the cribriform plate. We postulated that in one patient a congenital meningoencephalocele had originated from the foramen cecum. The protuberant tissue had enlarged along with the development of the fetus. Although the protuberant mass in the nasal cavity was large, there was no leak or a very mild leak in the skull base after cerebral tissue removal. No further skull base reconstruction is required. If the CSF leak or an encephalocele originates from the frontal sinus, the surgeon must simultaneously repair the skull base defect and maintain the patency of the frontal sinus. In our study, the defect in a 10-year-old child with traumatic CSF rhinorrhea was on the posterolateral wall of the frontal sinus, so we used a Draf III approach to expose the defect area. Although postoperative CT showed that this approach had an effect on the patient’s frontal sinus development (Fig. 2a, c), it was less effective than an open approach. A simple defect in the central sphenoid or perisellar regions can be approached through either a sphenoidotomy or the transethmoidal approach. For patients with CSF rhinorrhea or encephalocele on the lateral recess of the sphenoid, the sphenoid and pterygoid processes are usually overpneumatized, thereby causing unsatisfactory exposure of the area by routine transnasal endoscopy. The pterygoid approach should be used in these cases [13]. Castelnuovo et al. suggested that, in the presence of sufficient pneumatization, Sternberg’s canal—a lateral craniopharyngeal canal resulting from incomplete fusion of various sphenoid bone components—may be the site of origin of congenital meningoceles
or CSF fistulas [4]. It should be emphasized that, as an effect of intracranial pressure, normal spikes of CSF pressure may facilitate the development of small holes, resulting in herniation of dura/arachnoid or brain tissue [17]. There was a rare case of a 12-year-old girl who had an encephalocele in the lateral sphenoid recess. The transpterygoid approach provided adequate space for manipulation of reconstruction materials around the defect with little trauma. Skull base reconstruction technique After identification of a skull base defect and its exposure by the appropriate approach, the base of an encephalocele should be cauterized with bipolar cautery to ensure hemostasis. In the setting of an encephalocele, the brain tissue that has herniated into the nasal cavity is no longer functional and is considered to be a potential source of intracranial infection if not resected. Another important step is removal of the mucosa surrounding the defect site to allow the graft to adhere firmly to the skull base. Careful dissection of the intracranial dural border enables intracranial placement of the graft. This step is of great value for preventing recurrences related to skull growth in pediatric patients. The choice of graft material and its placement depends on the size of the defect and the experience of the surgeon. In our opinion, pedicled or free nasal mucosa or fascia is suitable if it is large enough to cover the fistula. We prefer an inlay technique with a rigid buttress (bone from the nasal septum or turbinates) and a vascularized flap (nasoseptal or middle turbinate) if the defect is large or the intracranial pressure is high. Vascularized flaps are not the only reconstructive tissue used, but when used, it is imperative that they adhere to the bony skull base. With regard to pediatric patients, it may be preferred to obtain grafts from the nasal cavities to avoid another incision. If there is no suitable nasal mucosa, we use temporalis fascia or fascia lata, because the healing process in fascia is rapid [10]. It is critical for the repair to have proper placement of the graft with tight packing for structural support. We place multiple layers of Gelfoam or other absorbable packing material underneath the graft. Iodoform gauze can promote growth of granulation tissue and be helpful for leak prevention. A removable finger cot can be placed under the packing material for additional support.
Conclusion The transnasal endoscopic approach for treating anterior skull base defects is minimally invasive, efficient, and safe in pediatric patients. Preoperative imaging, including CT and MRI, are of paramount importance in detection of the defect site and for choosing an appropriate operative approach and the proper reconstructive graft material. It must be emphasized that a
Childs Nerv Syst
skilled surgeon with experience in endoscopic nasal surgery is required to perform this surgical procedure. The appropriate instruments also play an important role in the operation. In the near future, larger clinical trials with longer follow-up times are warranted to confirm our conclusion.
8.
9. Conflict of interest The authors declare that they have no competing interests . Funding This study was funded by the Capital Medical Development Foundation of China (No. 2009-1035).
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Aarabi B, Leibrock LG (1992) Neurosurgical approaches to cerebrospinal fluid rhinorrhea. Ear Nose Throat J 71:300–305 Abdel-Aziz M, EI-Bosraty H, Qotb M, EI-Sonbaty M, Abdel-Badie H, Zynabdeen M (2010) Nasal encephalocele: endoscopic excision with anesthetic consideration. Int J Pediatr Otorhinolaryngol 74: 869–873 Blumenfeld R, Skolnik EM (1965) Intranasal encephaloceles. Arch Otolaryngol 82:527–531 Castelnuovo P, Dallan I, Pistochini A, Battaglia P, Locatelli D, Bignami M (2007) Endonasal endoscopic repair of Sternberg’s canal cerebrospinal fluid leaks. Laryngoscope 117:345–349 Di Rocco F, Couloigner V, Dastoli P, Sainte-Rose C, Zerah M, Roger G (2010) Treatment of anterior skull base defects by a transnasal endoscopic approach in children. J Neurosurg Pediatr 6:459–463 Hadad G, Bassagasteguy L, Carrau RL, Mataza JC, Kassam A, Snyderman CH, Mintz A (2006) A novel reconstructive technique after endoscopic expanded endonasal approaches: vascular pedicle nasoseptal flap. Laryngoscope 116:1882–1886 Kassam A, Thomas AJ, Snyderman C, Carrau R, Gardner P, Mintz A, Kanaan H, Horowitz M, Pollack IF (2007) Fully endoscopic
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expanded endonasal approach treating skull base lesions in pediatric patients. J Neurosurg 106:75–86 Locatelli D, Rampa F, Acchiardi I, Bignami M, Pistochini A, Casteknuovo P (2006) Endoscopic endonasal approaches to anterior skull base defects in pediatric patients. Childs Nerv Syst 22: 1411–1418 Mahajan C, Rath GP, Dash HH, Bithal PK (2011) Perioperative management of children with encephalocele: an institutional experience. J Neurosurg Anesthesiol 23:352–356 Martínez-Lage JF, Pérez-Espejo MA, Palaózn JH, López Hernández F, Puerta P (2006) Autologous tissues for dural grafting in children: a report of 56 cases. Childs Nerv Syst 22:139–144 Papay FA, Benninger MS, Levine HL, Lavertu P (1989) Transnasal transseptal endoscopic repair of sphenoidal cerebral spinal fluid fistula. Otolaryngol Head Neck Surg 101:595–597 Prevedello DM, Barges-Coll J, Fernandez-Miranda JC, Morera V, Jacobson D, Madhok R, dos Santos MC, Zanation A, Snyderman CH, Gardner P, Kassam AB, Carrau R (2009) Middle turbinate flap for skull base reconstruction: cadaveric feasibility study. Laryngoscope 119:2094–2098 Sautter NB, Batra PS, Citardi MJ (2008) Endoscopic management of sphenoid sinus cerebrospinal fluid leaks. Ann Otol Rhinol Laryngol 117:32–39 Steven RA, Rothera MP, Tang V, Bruce IA (2011) An unusual cause of nasal airway obstruction in a neonate: trans-sellar, trans-sphenoidal cephalocoele. J Laryngol Otol 125:1075– 1078 Suwanwela C, Suwanwela N (1972) A morphological classification of sincipital encephalomeningoceles. J Neurosurg 36: 201–211 Wormald PJ (2003) Salvage frontal sinus surgery: the endoscopic modified Lothrop procedure. Laryngoscope 113:276– 283 Zhou B, Han DM, Cui SJ, Zhang JL, Huang Q, Xian JF, Zhang L, Wei YX (2007) Endoscopic transpterygoid intervention of meningoencephalocele within lateral recess of sphenoid. Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 42:328–333, Chinese)
ORIGINAL PAPER
Endoscopic transnasal repair of cerebrospinal fluid leaks with and without an encephalocele in pediatric patients: from infants to children Jingying Ma 1 & Qian Huang 1 & Xiaokui Li 2 & Dongsheng Huang 3 & Junfang Xian 4 & Shunjiu Cui 1 & Yunchuan Li 1 & Bing Zhou 1
Received: 19 February 2015 / Accepted: 5 May 2015 # Springer-Verlag Berlin Heidelberg 2015
Abstract Purpose The diagnosis and management of pediatric cerebrospinal fluid (CSF) leak and encephalocele are challenging. The current study aimed to identify patient characteristics, review operative techniques, and evaluate the efficacy and safety of endoscopic endonasal repair in a pediatric population. Methods We retrospectively reviewed the records of pediatric patients who underwent transnasal endoscopic repair of CSF leak with or without a meningocele or an encephalocele at Beijing Tongren Hospital, Capital Medical University, between July 2003 and May 2014. All patients had preoperative radiological evaluations and underwent endoscopic endonasal repair of their skull base defects. Results Altogether, 23 children (mean age 7.0 years) underwent the procedures. Sixteen cases were congenital, and 7 patients had trauma history. The herniations or defects included meningoencephaloceles in 15 cases, meningoceles in 4 cases, and CSF leak in 4 cases (2 patients had bilateral leaks). The leak or herniation sites were ethmoid roof in 10 patients (one was bilateral), cribriform plate in 5, lateral to the
* Bing Zhou [email protected] 1
Department of Otolaryngology–Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, 1 Dongjiaominxiang Lane, Dongcheng District, Beijing 100730, China
2
Department of Anesthesiology, Beijing New Century Women’s and Children’s Hospital, Beijing, China
3
Department of Pediatrics, Beijing Tongren Hospital, Capital Medical University, Beijing, China
4
Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
foramen cecum in 3, posterior wall of the frontal sinus in 1, sphenoid sinus in 2, lateral recess of the sphenoid sinus in 1, and sella turcica base in 2. All subjects had favorable clinical outcomes without recurrence during a follow-up of 6– 123 months (mean 61.1 months). Conclusions The endoscopic endonasal approach was the preferred method for repairing CSF leaks with or without an encephalocele in pediatric patients. Compared to traditional operations, this endoscopic procedure is minimally invasive, efficient, and safe. Keywords Cerebrospinal fluid leak . Endoscopy . Encephalocele . Pediatric
Introduction Skull base defects are rarely identified in children. Causes of these defects include accidental trauma and iatrogenic trauma. They may also appear spontaneously or be congenital. Previous reports have shown that the incidence of congenital cerebrospinal fluid (CSF) leak with anterior basal encephalocele is approximately one in 4000–5000 live births [3, 15]. Congenital encephalocele is an open neural tube defect that allows herniation of the meninges and brain matter through a structural defect in the cranium [9]. Although these congenital defects are present at birth, it is likely that they are not diagnosed until the patient has symptoms of a CSF leak, meningitis, a facial deformity, or nasal obstruction. Over the past century, there have been many advances in surgical approaches to repairing skull base defects. As severe complications have been frequently reported following intracranial procedures, the focus has moved to extracranial approaches, including external ethmoidectomy and a transnasal approach. In 1989, Papay et al. reported clinical application of
Childs Nerv Syst
transnasal endoscopic CSF rhinorrhea repair [11]. The transnasal endoscopic approach has now been widely used in adults and has become the first-line treatment for repairing their anterior skull base defects. The general principles and results of endoscopic transnasal surgery in adults, however, cannot be directly extrapolated to infants and children. Thus, to date, this approach has not been evaluated in the pediatric population. The aim of the current study was to extend clinical experience with this procedure to pediatric patients and evaluate the effectiveness of endoscopic endonasal repair for CSF leak with or without the presence of encephalocele in that population.
Materials and methods From July 2003 to May 2014, a total of 23 pediatric patients (15 male, 8 female) underwent transnasal endoscopic repair for CSF leaks, meningoceles, and encephaloceles in the Department of Otolaryngology–Head and Neck Surgery of Beijing Tongren Hospital, Capital Medical University. Two patients underwent a bilateral operation. Patients’ ages ranged from 3 months to 14.0 years (mean 7.0 years). Formal consent is not required for this type of study. Preoperative preparation We reviewed the symptoms and signs, duration of symptoms at diagnosis, skull base defect localizations, causes, management, graft materials, recurrences, and complications. The infants underwent physical examination through a 2.7-mm endoscope and others throughout a 4.0-mm endoscope. All patients underwent computed tomography (CT) of the sinuses with a 2-mm slice bony window. When a mass in the nasal cavity was suspected, magnetic resonance (MR) images were obtained for a differential diagnosis. In cases of rhinorrhea, MRI cisternography (MRC) was undertaken to localize the leakage site. Operative procedures All defects were repaired using the endoscopic transnasal approach for skull base defects with 4.0- or 2.7-mm rigid endoscopes and microinstruments. Surgery was performed under general anesthesia, which was given intravenously in combination with inhaled anesthesia. Mucosal shrinking to minimize bleeding was induced by applying cotton strips soaked in tetracaine with 1:100,000 epinephrine solution. The first step of the surgery was to adequately expose the entire defect. The surgical approach varied depending on the site and size of the defect identified by preoperative imaging. Routine ethmoidectomy was performed for defects in the ethmoid roof or cribriform plate. A Draf III procedure [16] was
performed for defects in the frontal sinus. Defects in the central sphenoid regions were approached via direct sphenoidotomy or transethmoidally. A transpterygoid approach [17] was used to access the sphenoid sinus for defects in the lateral recess of the sphenoid. Following defect exposure, bipolar cautery was used to coagulate and resect meningoceles and encephaloceles. When dissecting tight adhesions between the mucosa and bone, the mucosa was dissected about 5 mm around the leak site, and careful bipolar cautery coagulation was applied. A variety of soft tissue materials—temporalis fascia, free mucosal grafts from middle turbinates, vascularized nasoseptal [6] or middle turbinate [12] flaps—were used for underlay or overlay grafts. For rigid grafting, we used bone grafts from the nasal septum or middle turbinate. Finally, we placed absorbable packing material (e.g., Gelfoam) and/or iodoform gauze underneath the graft for 2–3 weeks. Postoperative care and follow-up All patients received intravenous antibiotic prophylaxis (thirdgeneration cephalosporin) postoperatively. Endoscopic cleanup included removing the iodoform gauze under general anesthesia within 3 weeks after the surgery. The patients were then evaluated endoscopically every 2–4 weeks until epithelialization of the mucous membrane was apparent and thereafter once a year. CT examination was performed in all patients 12– 24 months after the surgery.
Results In all, 16 (69.6 %) of the defects were congenital, and 7 (30.4 %) had been caused by trauma. Among the 23 children, 12 had a major symptom of CSF rhinorrhea, 6 had a history of meningitis, 2 had recurrent pneumonia, and 12 complained of nasal obstruction. It should be noted that nine infants less than 1 year of age were identified by their symptoms of nasal obstruction, including mouth breathing and feeding difficulties. In 14 patients, nasal endoscopy found, upon the patients’ crying, a unilateral polypoid mass with enlargement in the nasal cavity. The clinical characteristics, including age, cause, symptom, type of herniation, and location, among other items of interest are shown in Table 1. CT clearly revealed skull base fractures or defects in 22 cases (Fig. 1a). Unilateral soft tissue shadows in the sinus with skull base defects were found in 14 patients (by CT in 7 cases, by CT and MRI for 7 cases) (Fig. 2a–c). MRC revealed lineshaped high-signal connections between high-signal intracranial CSF and high-signal CSF in the nasal cavity in 8 patients. The exact location of the CSF leak was detectable by CT or MRI in all but one patient, in whom it was identified during surgical exploration.
Childs Nerv Syst Table 1
Clinical characteristics of 23 patients with skull base defects
Age
Symptoms
Type of herniation
Location
Defect size (mm2)
Graft
4 months 6 years 10 years 4 months
Nasal obstruction Nasal obstruction Meningitis Nasal obstruction
ME ME M ME
Cribriform plate Base of sella turcica Ethmoid roof Ethmoid roof
4 150 16 4
TF PNSF+fascia lata UPM TF
12 months 14 years 13 years 13 years 12 months 16 months 8 years 11 years 11 months 12 years
Nasal obstruction, rhinorrea, meningitis Nasal obstruction Rhinorrea Nasal obstruction, rhinorrea Nasal obstruction Rhinorrea Meningitis Rhinorrea Nasal obstruction, rhinorrea, pneumonia Nasal obstruction, rhinorrea
ME ME None ME ME ME ME M ME None
3 months 10 years 12 years 13 years 7 months 11 years 5 months
Nasal obstruction Rhinorrea Rhinorrea, meningitis Rhinorrea, meningitis Nasal obstruction Meningitis Nasal obstruction
ME None M ME ME None ME
Ethmoid roof Cribriform plate (Bilateral) ethmoid roof Ethmoid roof Cribriform plate Ethmoid roof Ethmoid roof Ethmoid roof Cribriform plate (Right) ethmoid roof (Left) lateral wall of sphenoid Cribriform plate Posterior wall of frontal sinus Lateral recess of sphenoid Cribriform plate Cribriform plate Cribriform plate Base of sella turcica
150 50 4 18 None 9 144 120 45 25 4 None 25 4 64 None 6 None
Artificial bone+PNSF MTB+PNSF (Bilateral) MTM MTB+PNSF None MTB+TF MTB+TF MTB+PNSF PMTF (Right) PSTF (Left) PSTF None TF TF MTB+MTM None PMTF None
5 months 13 years
Nasal obstruction, rhinorrhea, pneumonia Rhinorrea
ME None
Ethmoid roof Lateral wall of sphenoid
70 4
PNSF MTM
ME Meningo-encephalocele, M Meningocele, TF temporalis fascia, UPM mucosa of uncinate process, PNSF Pedicled nasoseptal flap, PMTF Pedicled middle turbinate flap, PSTF Pedicled superior turbinate flap, NSB nasoseptal bone, MTB middle turbinate bone, MTM middle turbinate mucosa
The herniations were identified as meningoencephaloceles in 15 cases, meningoceles in 3 patients, and CSF leaks in 5 patients (2 patients had bilateral leaks). The leak sites were successfully located in the ethmoid roof in 10 patients (1 case was bilateral), cribriform plate in 5, posterior wall of the
frontal sinus in 1, sphenoid sinus in 2 (the leak on the other side was in the ethmoid roof), lateral recess of the sphenoid sinus in 1, and base of the sella turcica in 2. In the other three patients, encephaloceles were located lateral to the foramen cecum and anterior to the cribriform plate. The defect in the
Fig. 1 Ten-year-old patient with traumatic cerebrospinal fluid (CSF) leak at the posterior wall of the frontal sinus. An improved Draf III procedure was performed to reveal the leak location, which was repaired with temporalis fascia. At the 24-month follow-up, the patient was doing well without further seizures, infection, or CSF leak. a Coronal computed
tomography (CT) shows a skull base defect (white arrow). b Defect in the posterior wall of the right frontal sinus shown by the Draf III approach (white arrow). c Postoperative CT scan shows that the defect had been repaired (white arrow)
Childs Nerv Syst Fig. 2 Coronal (a) and sagittal (b) CT scans demonstrate a large intranasal mass with an associated anterior skull base defect (white arrow). c MRI shows that a meningoencephalocele is clearly visible in the left nasal fossa (white arrow)
posterior wall of the frontal sinus was repaired using a Draf III procedure (Fig. 1b, c), and the defect in the sphenoid lateral recess was repaired via transpterygoid intervention. The others underwent routine endoscopic sinus operations. The defects measured 4–150 mm2. In four patients, no defect was found after removal of a nasal mass. Pathologic assessment of these masses identified them as brain tissue, so no further repair was necessary. The soft reconstructive materials for 13 defects in 11 patients consisted of temporalis fascia (n=4), free mucosal grafts from the uncinate process (n=2) and middle turbinate (n=2), a vascularized nasoseptal flap (n=3, one with fascia lata), and a vascularized middle turbinate flap (n=4). For the other seven relatively larger skull base defects, we used a multilayer repair technique that consisted of combined soft tissue graft and rigid graft, including nasoseptal bone with a vascularized nasoseptal flap (n=3), middle turbinate bone with temporalis fascia (n=2), middle turbinate bone with mucosa (n=1), and artificial bone with a vascularized nasoseptal flap (n=1). The mean duration of the operation was 134 min (range 60–240 min). The mean amount of bleeding was 20.0 ml (range 5–50 ml). None of our patients developed any intraoperative or postoperative complications or required further revision surgery. We had a 100 % success rate with a mean follow-up of 61.1 months (range 6–123 months).
Discussion
dehiscence in the skull base and provide important bony details to help choose the surgical approach. In contrast, MRI is able to clearly distinguish brain parenchyma and CSF that have herniated into the sinus. Efficacy and safety of endoscopic repair Surgical repair of skull base defects is performed to prevent meningitis, intracranial abscess, and the growth’s influence on nasal obstruction, oral breathing, and feeding difficulties. Traditionally, these defects have been managed via craniotomy or lateral rhinotomy. A number of studies have reported a 40 % recurrence rate with these approaches, however, and significant morbidity including anosmia, memory deficits, loss of smell, and intracranial hemorrhage [1]. In the past, timing of the repair focused on allowing adequate time for growth to avoid those complications. Since the early 1980s, however, the transnasal endoscopic approach has progressively become the first-line treatment for repairing anterior skull base defects in adults, with success rates up to 90 % [16]. These results, however, cannot be simply applied to pediatric patients whose nasal cavities are narrow. Our study shows that endoscopic endonasal repair of skull base defects is a safe and efficient approach in pediatric patients, which is in line with prior reports [7, 8]. Importantly, all of our patients had a quick recovery without complications. Also, there is no age limit for endoscopic endonasal surgery. Notably, the youngest reported patient was 1.5 months [5]. The youngest patient in our study was 3 months, and nine children were younger than 1 year of age.
Clinical feature and diagnosis Special considerations for pediatric patients A pediatric skull base defect is rare and challenging in regard to diagnosis and management. Nasal encephaloceles are sometimes asymptomatic, whereas others manifest as nasal obstruction, oral breathing, and headache. Others are associated with CSF rhinorrhea or, rarely, meningitis. The defect may present at birth as a mass in the nose causing upper airway obstruction [14]. Nasal obstruction was observed in 12 of our 23 patients, including nine infants less than 1 year of age. Therefore, encephalocele should be suspected when a child presents with a unilateral nasal mass. It can be confirmed by endoscopy and/or radiologic imaging. CT may locate
The endoscopic endonasal technique still has some indications. Experience in the management of intracranial pathologies of otolaryngologists is an important premise. Minimizing the potential serious risk of pneumonia, meningitis, and other intracranial complications is paramount in the decision making process. The choice of timing for the surgery should be discussed. Among our patients, two had rhinorrhea and recurrent pneumonia. We chose a Btime window^ during which to perform their operations based on when their temperatures returned to normal after antibiotic treatment by their pediatricians. After surgery,
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neither patient had a recurrence of pneumonia, presumably because rhinorrheal stimulation was no longer present. The endoscopic procedure is technically difficult in pediatric patients because of their narrow nasal cavities. Thin, rigid endoscopes (external diameter 2.7 mm) and some microinstruments can be applied and are helpful. It may be difficult to maintain fluid balance in pediatric patients, particularly in those with mannitol therapy or blood loss. As suggested by Abdel-Aziz et al. [2], oversedation of infants should be avoided as it may result in decreased respiratory effort and increased intracranial pressure secondary to hypercarbia. Careful surgery and application of electric coagulation and cotton strips soaked in epinephrine can reduce bleeding. The use of minor cotton strips also could protect the mucosa. Cooperation between experienced surgeons and anesthetists is thus critical for obtaining the best clinical outcomes. Endoscopic operative approach The appropriate surgical approach varies depending on the exact site and size of the defect, equipment availability, and the experience of the surgeon. Lesions in the ethmoid roof and on the cribriform plate are not difficult to manage with ethmoidectomy. In three infants of our study, the roots of brain tissue were found lateral to the foramen cecum, anterior to the cribriform plate. We postulated that in one patient a congenital meningoencephalocele had originated from the foramen cecum. The protuberant tissue had enlarged along with the development of the fetus. Although the protuberant mass in the nasal cavity was large, there was no leak or a very mild leak in the skull base after cerebral tissue removal. No further skull base reconstruction is required. If the CSF leak or an encephalocele originates from the frontal sinus, the surgeon must simultaneously repair the skull base defect and maintain the patency of the frontal sinus. In our study, the defect in a 10-year-old child with traumatic CSF rhinorrhea was on the posterolateral wall of the frontal sinus, so we used a Draf III approach to expose the defect area. Although postoperative CT showed that this approach had an effect on the patient’s frontal sinus development (Fig. 2a, c), it was less effective than an open approach. A simple defect in the central sphenoid or perisellar regions can be approached through either a sphenoidotomy or the transethmoidal approach. For patients with CSF rhinorrhea or encephalocele on the lateral recess of the sphenoid, the sphenoid and pterygoid processes are usually overpneumatized, thereby causing unsatisfactory exposure of the area by routine transnasal endoscopy. The pterygoid approach should be used in these cases [13]. Castelnuovo et al. suggested that, in the presence of sufficient pneumatization, Sternberg’s canal—a lateral craniopharyngeal canal resulting from incomplete fusion of various sphenoid bone components—may be the site of origin of congenital meningoceles
or CSF fistulas [4]. It should be emphasized that, as an effect of intracranial pressure, normal spikes of CSF pressure may facilitate the development of small holes, resulting in herniation of dura/arachnoid or brain tissue [17]. There was a rare case of a 12-year-old girl who had an encephalocele in the lateral sphenoid recess. The transpterygoid approach provided adequate space for manipulation of reconstruction materials around the defect with little trauma. Skull base reconstruction technique After identification of a skull base defect and its exposure by the appropriate approach, the base of an encephalocele should be cauterized with bipolar cautery to ensure hemostasis. In the setting of an encephalocele, the brain tissue that has herniated into the nasal cavity is no longer functional and is considered to be a potential source of intracranial infection if not resected. Another important step is removal of the mucosa surrounding the defect site to allow the graft to adhere firmly to the skull base. Careful dissection of the intracranial dural border enables intracranial placement of the graft. This step is of great value for preventing recurrences related to skull growth in pediatric patients. The choice of graft material and its placement depends on the size of the defect and the experience of the surgeon. In our opinion, pedicled or free nasal mucosa or fascia is suitable if it is large enough to cover the fistula. We prefer an inlay technique with a rigid buttress (bone from the nasal septum or turbinates) and a vascularized flap (nasoseptal or middle turbinate) if the defect is large or the intracranial pressure is high. Vascularized flaps are not the only reconstructive tissue used, but when used, it is imperative that they adhere to the bony skull base. With regard to pediatric patients, it may be preferred to obtain grafts from the nasal cavities to avoid another incision. If there is no suitable nasal mucosa, we use temporalis fascia or fascia lata, because the healing process in fascia is rapid [10]. It is critical for the repair to have proper placement of the graft with tight packing for structural support. We place multiple layers of Gelfoam or other absorbable packing material underneath the graft. Iodoform gauze can promote growth of granulation tissue and be helpful for leak prevention. A removable finger cot can be placed under the packing material for additional support.
Conclusion The transnasal endoscopic approach for treating anterior skull base defects is minimally invasive, efficient, and safe in pediatric patients. Preoperative imaging, including CT and MRI, are of paramount importance in detection of the defect site and for choosing an appropriate operative approach and the proper reconstructive graft material. It must be emphasized that a
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skilled surgeon with experience in endoscopic nasal surgery is required to perform this surgical procedure. The appropriate instruments also play an important role in the operation. In the near future, larger clinical trials with longer follow-up times are warranted to confirm our conclusion.
8.
9. Conflict of interest The authors declare that they have no competing interests . Funding This study was funded by the Capital Medical Development Foundation of China (No. 2009-1035).
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