Accepted Manuscript Endoscopic middle cranial fossa reconstruction via a subtemporal keyhole: A technical note Fuminari Komatsu, M.D., Ph.D, Masaaki Imai, M.D., Ph.D, Akihiro Hirayama, M.D., Ph.D, Naokazu Hayashi, M.D., Ph.D., Shinri Oda, M.D., Ph.D, Masami Shimoda, M.D., Ph.D, Mitsunori Matsumae, M.D., D.M.Sc PII:
S1878-8750(17)31454-7
DOI:
10.1016/j.wneu.2017.08.153
Reference:
WNEU 6403
To appear in:
World Neurosurgery
Received Date: 30 April 2017 Revised Date:
22 August 2017
Accepted Date: 23 August 2017
Please cite this article as: Komatsu F, Imai M, Hirayama A, Hayashi N, Oda S, Shimoda M, Matsumae M, Endoscopic middle cranial fossa reconstruction via a subtemporal keyhole: A technical note, World Neurosurgery (2017), doi: 10.1016/j.wneu.2017.08.153. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Komatsu et al.
ACCEPTED MANUSCRIPT
Endoscopic middle cranial fossa reconstruction via a subtemporal keyhole: A technical note
RI PT
Fuminari Komatsu, M.D., Ph.D.1, Masaaki Imai, M.D., Ph.D.1, Akihiro Hirayama, M.D., Ph.D.1, Naokazu Hayashi, M.D., Ph.D.1, Shinri Oda, M.D., Ph.D.1, Masami Shimoda, M.D., Ph.D.1, and Mitsunori Matsumae, M.D., D.M.Sc.2
Department of Neurosurgery, Tokai University Hachioji Hospital, Tokyo, Japan
2
Department of Neurosurgery, Tokai University School of Medicine, Kanagawa, Japan
M AN U
SC
1
Corresponding author: Fuminari Komatsu
Department of Neurosurgery, Tokai University Hachioji Hospital
TE D
1838 Ishikawa-machi, Hachioji, Tokyo, 192-0032, Japan E-mail: [email protected]
EP
Tel: +81 42-639-1111, Fax: +81 42-639-1112
AC C
Key words: endoscopy, minimally invasive surgery, skull base
Abbreviations list:
CSF, cerebrospinal fluid; CT, computed tomography; DTF, deep temporal fascia; IAM, internal acoustic meatus; MCF, middle cranial fossa; MR, magnetic resonance; STF, superficial temporal fascia; TM, temporal muscle; VDF, vascularized deep temporal fascial flap
1
Komatsu et al.
ACCEPTED MANUSCRIPT
Abstract Background Skull base reconstruction is an essential technique for repairing cerebrospinal fluid (CSF)
RI PT
leakage. A reliable method for middle cranial fossa (MCF) reconstruction with minimal invasiveness has not been reported. An initial case of endoscopic MCF reconstruction via a subtemporal keyhole is described. Case description
SC
A 57-year-old man developed severe meningitis and was diagnosed with spontaneous CSF leakage from bone defects on the tegmen tympani. Endoscopic MCF reconstruction via a
M AN U
subtemporal keyhole was carried out. Three skin incisions, including one subtemporal incision for a subtemporal keyhole and two temporal line incisions on the superior temporal line, were made, and a 0-degree endoscope was introduced into the subcutaneous space. The deep temporal fascia (DTF) was bluntly dissected and separated from both the superficial
TE D
temporal fascia and temporal muscle, and the DTF was incised to shape a pedicled flap under endoscopic view. Blood supply to the pedicled DTF flap was confirmed with indocyanine green angiography. A subtemporal keyhole was then made, and a 30-degree endoscope was used to explore the extradural space of the MCF floor, visualizing the bone
EP
defects on the tegmen tympani well. The vascularized DTF flap passed easily through the subtemporal keyhole and adequately overlaid the bone defects. The patient’s postoperative
AC C
course was uneventful, and CSF leakage disappeared without mastication problems. Conclusions
This purely endoscopic technique using a vascularized DTF flap provided reliable MCF reconstruction through a subtemporal keyhole. This technique is also expected to be applicable for MCF reconstruction after subtemporal keyhole surgery for skull base tumors.
2
Komatsu et al.
ACCEPTED MANUSCRIPT
Introduction Reconstruction of the skull base is an essential technique to repair cerebrospinal fluid (CSF) leakage attributed to spontaneous, post-traumatic, and postoperative conditions. Endoscopic
RI PT
endonasal surgery established minimally invasive reconstruction methods using the vascularized septal mucosal flap for CSF leakage from the anterior midline skull base, and these methods have been widely accepted for postoperative skull base reconstruction
following surgery for anterior midline skull base tumors, contributing to the development of
SC
endoscopic endonasal skull base surgery.1-4
On the other hand, excellent results of transcranial keyhole surgery for tumors have been
M AN U
reported so far,5, 6 but skull base reconstruction through a keyhole, especially subtemporal keyhole surgery to the middle cranial fossa (MCF), has only been discussed. Therefore, we previously investigated a novel reconstruction technique in a cadaver study and reported the potential advantages of endoscopic subtemporal MCF reconstruction using the deep
TE D
temporal fascia (DTF) (Fig. 1).7 The newly developed endoscopic technique is able to harvest a vascularized DTF flap, to allow access to the whole surface of the MCF floor, and to apply the vascularized DTF flap on the MCF via a subtemporal keyhole with minimal invasiveness. The nuances of and initial clinical experience with endoscopic subtemporal
EP
MCF reconstruction are presented.
AC C
Case description
A 57-year-old man developed severe meningitis with otorrhea and aural fullness. He had no history of head injury or otolaryngological diseases, and his body mass index was 23.0 kg/m2, indicating that he was not obese. Computed tomography (CT) and 3-dimensional CT revealed effusion in the left tympanic cavity and mastoid air cells (Fig. 2A). A group of small temporal bone defects, each with a diameter of approximately 2 mm, and slight pneumocephalus around the bone defects were seen on the tegmen tympani (Fig. 2B, C). Another bone defect, which was 3.5 mm in diameter and apart from the pneumocephalus,
3
Komatsu et al.
ACCEPTED MANUSCRIPT
was observed lateral to the groove for the greater superficial petrosal nerve (Fig. 2C). Magnetic resonance (MR) cisternography did not show any encephalocele. The clinical diagnosis was spontaneous CSF leakage from the bone defects on the tegmen tympani.
RI PT
Endoscopic subtemporal MCF reconstruction was carried out (Video 1). The institutional ethics committee approved this approach, and informed consent was obtained from the
patient. After insertion of the spinal drainage, the head was fixed so that the sagittal plane was parallel to the ground, and three skin incisions, including one subtemporal incision for a
SC
subtemporal keyhole and two temporal line incisions, were made. The anterior temporal line incision was located 2.0 cm anterior to the vertebral line on the zygomatic root, and the
M AN U
anterior and posterior temporal line incisions were 4.0 cm apart on the superior temporal line (Fig. 1A). A 4-mm 0-degree endoscope and a dissector were inserted from one temporal line incision, and the subcutaneous space was explored with blunt soft tissue dissection. As the dissection proceeded, an assistant elevated the cutaneous tissue using
TE D
other dissectors through another temporal line and/or subtemporal incisions to create working space (Fig. 3A). The DTF was separated from the superficial temporal fascia (STF), and then the DTF was elevated from the temporal muscle (Fig. 3B). Thus, the DTF was separated from both the STF and temporal muscle. Furthermore, the DTF was incised,
EP
shaping the pedicled DTF flap attached on the upper rim of the zygomatic arch (Fig. 3C, D). Blood supply from the middle temporal artery to the harvested DTF flap was shown by
AC C
indocyanine green angiography under microscopy (Fig. 3E). After harvesting the DTF flap, a subtemporal keyhole was placed after splitting of the temporal muscle along the subtemporal incision just above the zygomatic root. A 4-mm 30-degree endoscope was advanced into the extradural space of the MCF with elevation of the temporal dura mater to inspect the MCF floor. The groove for the greater superficial petrosal nerve was not exposed. The angled endoscope provided good visualization of the irregular surface of the MCF floor and detected the bone defects on the tegmen tympani and lateral to the groove for the greater superficial petrosal nerve (Fig. 3F, G). The bone defects on the tegmen
4
Komatsu et al.
ACCEPTED MANUSCRIPT
tympani were covered by membranous tissue. No obvious dural tear was observed on the temporal dura mater. It was impossible to distinguish which bone defect was responsible for the CSF leakage. The vascularized DTF flap was applied on the MCF floor through the
RI PT
subtemporal keyhole, and all temporal bone defects were adequately overlaid by the vascularized DTF flap and then fixed by fibrin glue (Fig. 3H). Rigid reconstruction was not performed because of the small bone defects. The subtemporal keyhole was closed with
care to preserve the blood supply to the DTF flap. Surgical time was 3.5 hours. The spinal
SC
drainage was removed immediately after the operation. The patient’s postoperative course was uneventful. CSF leakage and the effusion in the tympanic cavity on CT disappeared
M AN U
postoperatively (Fig. 2D). Gadolinium-enhanced MR imaging showed the DTF flap on the MCF floor (Fig 2E). An audiogram showed no conductive hearing loss. No signs of intracranial hypertension, such as papilledema, elevated opening pressure on lumbar puncture, and empty sella on MR imaging, were seen postoperatively. The patient had no
Discussion
TE D
difficulties with mastication. No recurrence was observed for 18 months.
Vascularized pedicle tissue has been recommended for skull base reconstruction because it
EP
significantly decreases the incidence of CSF leakage,1, 2, 8, 9 and the vascularized temporal
muscle flap has been commonly used for MCF reconstruction.10, 11 Although a temporal
AC C
muscle flap is effective to repair CSF leakage from the MCF, postoperative pain, mastication problems, trismus, and poor cosmetic results continue.11, 12 In addition, massive and bulky temporal muscle cannot be passed through the subtemporal keyhole, and rotational flexibility to temporal bone defects is limited. Therefore, a temporal muscle flap has not been used for subtemporal keyhole surgery. Novel endoscopic technique enables harvesting of the vascularized DTF flap from three small skin incisions with preservation of the temporal muscle, and it overcomes the disadvantages of the temporal muscle flap. The DTF anatomically receives its blood supply
5
Komatsu et al.
ACCEPTED MANUSCRIPT
from the middle temporal artery,7, 13, 14 and a robust blood supply to the DTF flap was confirmed by indocyanine green angiography. Regarding endoscopic manipulation in the MCF, a 30-degree endoscope provided good visualization of the irregular surface of the
RI PT
MCF floor even behind corners, and it detected temporal bone defects precisely with superb magnification. The thin but durable DTF flap had a small volume of tissue, and it therefore passed easily through the subtemporal keyhole. The DTF flap had a narrow pedicle, a long arc of rotation, and distant reach, contributing to coverage of a large surface on the MCF at
SC
an arbitrary location even under endoscopy.7 Rigid reconstruction using autograft bone or synthetic material was not performed in the present case because of the small bone defects,
M AN U
but it would be technically possible if needed. The CSF leakage from the temporal bone defects was successfully repaired, and preservation of the temporal muscle contributed to no mastication problems and excellent cosmetic results.
Potential complications include injury of the internal carotid artery in the carotid canal.
TE D
Endoscopic manipulation in the MCF may bring the risks of carotid injury in some cases of osseous deficiency on the petrous internal carotid artery. Pre-operative evaluation of neuroimages and careful identification using anatomical landmarks and navigation are mandatory.
hemostatic agents.
EP
In contrast, venous bleeding from the venous system would be properly controlled by
The risk of facial nerve palsy with this technique is also a potential concern in two phases.
AC C
First, the frontal branch of the facial nerve must be carefully protected during the harvest of the DTF flap. The anterior temporal line incision should not extend anteriorly, and dissection must be kept within the appropriate layers, to avoid the running course of the frontal branch of the facial nerve. Second, the greater superficial petrosal nerve must be preserved during extradural dissection of the MCF. Facial nerve monitoring would contribute to avoiding this complication. Although this is a case report and the patient still requires a long period of follow-up, this technique appears to be an effective, safe, and reliable approach for MCF reconstruction
6
Komatsu et al.
ACCEPTED MANUSCRIPT
with minimal invasiveness. This technique is also expected to be useful in MCF reconstruction after purely endoscopic or endoscope-assisted subtemporal keyhole surgery
RI PT
for skull base tumors.15, 16
Conclusions
An initial case of endoscopic MCF reconstruction by subtemporal keyhole surgery was
described. The vascularized DTF flap was flexible, long, and large enough to overlay bone
SC
defects on the MCF, overcoming the problems related to temporal muscle. This endoscopic
M AN U
technique could be a valid alternative for MCF reconstruction.
Acknowledgements
The authors greatly appreciate the assistance of Professor Manfred Tschabitscher of Brescia
TE D
University, Italy, for teaching the endoscopic anatomy related to this surgical technique, and Dr. Mika Komatsu of Ohta Neurosurgical Clinic, Japan, for cooperation with previous
AC C
Funding
EP
anatomical studies and cordial advice regarding this study.
This study did not receive any specific grants from funding agencies in the public, commercial, or not-for-profit sectors.
Declaration of interest Conflicts of interest: none
Role of the funding source Not applicable. 7
Komatsu et al.
ACCEPTED MANUSCRIPT
References 1.
Hadad G, Bassagasteguy L, Carrau RL, Mataza JC, Kassam A, Snyderman CH, et al.
RI PT
A novel reconstructive technique after endoscopic expanded endonasal approaches: vascular pedicle nasoseptal flap. Laryngoscope. 2006;116:1882-1886. 2.
Kassam AB, Thomas A, Carrau RL, Snyderman CH, Vescan A, Prevedello D, et al.
SC
Endoscopic reconstruction of the cranial base using a pedicled nasoseptal flap.
3.
M AN U
Neurosurgery. 2008;63:ONS44-52; discussion ONS-53.
Thorp BD, Sreenath SB, Ebert CS, Zanation AM. Endoscopic skull base reconstruction: a review and clinical case series of 152 vascularized flaps used for surgical skull base defects in the setting of intraoperative cerebrospinal fluid leak.
4.
TE D
Neurosurg Focus. 2014;37:E4.
Horiguchi K, Nishioka H, Fukuhara N, Yamaguchi-Okada M, Yamada S. A new
EP
multilayer reconstruction using nasal septal flap combined with fascia graft dural suturing for high-flow cerebrospinal fluid leak after endoscopic endonasal surgery.
5.
AC C
Neurosurg Rev. 2016;39:419-427. Taniguchi M, Perneczky A. Subtemporal keyhole approach to the suprasellar and petroclival region: microanatomic considerations and clinical application.
Neurosurgery. 1997;41:592-601. 6.
Berhouma M, Jacquesson T, Jouanneau E. The fully endoscopic supraorbital transeyebrow keyhole approach to the anterior and middle skull base. Acta Neurochir (Wien). 2011;153:1949-1954. 8
Komatsu et al.
ACCEPTED MANUSCRIPT
7.
Komatsu M, Komatsu F, Di Ieva A, Inoue T, Tschabitscher M. Endoscopic reconstruction of the middle cranial fossa through a subtemporal keyhole using a
RI PT
pedicled deep temporal fascial flap: a cadaveric study. Neurosurgery. 2012;70:157161; discussion 162. 8.
Fattahi T, Dipasquale J. Utility of the pericranial flap in frontal sinus and anterior
Taha M, Carroll T, McMahon J. Vascularized temporoparietal fascial flap for the
M AN U
9.
SC
cranial fossa trauma. Int J Oral Maxillofac Surg. 2009;38:1263-1267.
treatment of a traumatic cerebrospinal fluid fistula in the middle cranial fossa. Technical note. J Neurosurg. 2009;111:393-395. 10.
Cantu G, Solero CL, Riccio S, Colombo S, Pompilio M, Aboh IV, et al. Surgery for
2010;20:55-60.
Gonen L, Handzel O, Shimony N, Fliss DM, Margalit N. Surgical management of
EP
11.
TE D
malignant maxillary tumors involving the middle cranial fossa. Skull Base.
spontaneous cerebrospinal fluid leakage through temporal bone defects--case series
12.
AC C
and review of the literature. Neurosurg Rev. 2016;39:141-150; discussion 150. Olson KL, Manolidis S. The pedicled superficial temporalis fascial flap: a new
method for reconstruction in otologic surgery. Otolaryngol Head Neck Surg. 2002;126:538-547.
13.
Krayenbuhl N, Isolan GR, Hafez A, Yasargil MG. The relationship of the frontotemporal branches of the facial nerve to the fascias of the temporal region: a
9
Komatsu et al.
ACCEPTED MANUSCRIPT
literature review applied to practical anatomical dissection. Neurosurg Rev. 2007;30:8-15. Beheiry EE, Abdel-Hamid FA. An anatomical study of the temporal fascia and
RI PT
14.
related temporal pads of fat. Plast Reconstr Surg. 2007;119:136-144. 15.
Komatsu F, Komatsu M, Di Ieva A, Tschabitscher M. Endoscopic extradural
SC
subtemporal approach to lateral and central skull base: a cadaveric study. World
Komatsu F, Komatsu M, Di Ieva A, Tschabitscher M. Endoscopic approaches to the trigeminal nerve and clinical consideration for trigeminal schwannomas: a cadaveric
EP
TE D
study. J Neurosurg. 2012;117:690-696.
AC C
16.
M AN U
Neurosurg. 2013;80:591-597.
10
Komatsu et al.
ACCEPTED MANUSCRIPT
Figure Legends Figure 1. Outline of the endoscopic subtemporal MCF reconstruction. A, The design of the skin
RI PT
incisions is shown. The green line indicates the subtemporal incision for subtemporal keyhole craniotomy, and the two yellow lines mark the temporal line incisions used for
endoscopic manipulation to harvest a pedicled DTF flap. B, Endoscopic harvest of the DTF flap is illustrated. The operator uses one temporal line incision to introduce the endoscope
SC
and a dissector (asterisk) to harvest the DTF. The assistant introduces another dissector (double asterisks) via another temporal line incision and creates a working space with skin
M AN U
elevation. The DTF is incised to form the pedicled flap with subcutaneous manipulation under endoscopy. C, Endoscopic exploration of the MCF is shown. The endoscope is introduced into the extradural space of the MCF floor through the subtemporal keyhole, and it illuminates the bone defect (red dimple) on the tegmen tympani. The pedicled DTF flap is
on the bone defect.
Figure 2.
TE D
reflected through the subtemporal incision. D, The pedicled DTF flap is adequately overlaid
EP
Pre-(A, B, C) and post-(D, E) operative neuro-images of the case presented. A, CT shows an effusion in the left tympanic cavity and mastoid air cells (yellow arrow). B, Slight
AC C
pneumocephalus around the left tegmen tympani is shown (white arrow). C, 3D-CT indicates a group of small bone defects (green dotted circle) on the left tegmen tympani and another bone defect (blue arrow) lateral to the groove for the greater superficial petrosal nerve. D, Postoperative CT shows disappearance of the effusion in the left tympanic cavity and mastoid air cells. E, Coronal view of gadolinium-enhanced MR image demonstrates the DTF flap (red arrow heads) overlaid on the MCF floor. IAM, internal acoustic meatus.
Figure 3.
11
Komatsu et al.
ACCEPTED MANUSCRIPT
Intra-operative findings of the case presented. Endoscopic harvest of a vascularized DTF flap is shown in A, B, C, and D. A, The operator inserts a 4-mm 0-degree endoscope through one temporal incision, while an assistant elevates the cutaneous tissue by dissectors
RI PT
(asterisks) through another temporal line and subtemporal incisions to create working space. The DTF is separated from the STF. B, The DTF is elevated from the temporal muscle. C, The DTF is incised to form the DTF flap. D, The harvested DTF flap measures 7.0 cm × 1.5 cm × 4.0 cm (length × width at base × width at distal end). E, Indocyanine green
SC
angiography of the harvested DTF flap under microscopy. The blood supply from the middle temporal artery to the harvested DTF flap is depicted by indocyanine green
M AN U
angiography under microscopy (white arrow). Endoscopic views of the extradural MCF floor are shown in F, G, and H. F, G, A 4-mm 30-degree endoscope is advanced into the extradural space of the MCF with elevation of the temporal dura mater, and the bone defects on the tegmen tympani (green dotted circle) (G) and lateral to the groove for the greater
TE D
superficial petrosal nerve (blue arrow) (F) are detected. The bone defects on the tegmen tympani are covered by membranous tissue. H, All temporal bone defects are adequately overlaid by the vascularized DTF flap. DTF, deep temporal fascia; STF, superficial
Video legends
EP
temporal fascia; TM, temporal muscle; VDF, vascularized deep temporal fascial flap
AC C
Endoscopic harvest of a vascularized DTF flap. After making three skin incisions, including a subtemporal and two other small incisions on the superior temporal line, a 4mm 0-degree endoscope and instruments are inserted into the subcutaneous layers. The STF and DTF are bluntly separated, and the space between the STF and DTF is connected through the three skin incisions. Then, the DTF is elevated from the temporal muscle via the two temporal line incisions. Thus, the DTF is separated from both the STF and temporal muscle. Furthermore, the DTF is incised, shaping the pedicled DTF flap attached on the upper rim of the zygomatic arch.
12
Komatsu et al.
ACCEPTED MANUSCRIPT
The blood supply from the middle temporal artery to the harvested DTF flap is depicted by indocyanine green angiography under microscopy. Endoscopic reconstruction of the MCF floor. A 30-degree endoscope is advanced into the
RI PT
extradural space of the MCF. First, a bone defect lateral to the groove for the greater superficial petrosal nerve (blue arrow) comes into view. Then, a group of bone defects on the tegmen tympani (green dotted circle) are identified, and these are covered with
membranous tissue. All temporal bone defects are adequately overlaid by the vascularized
AC C
EP
TE D
M AN U
muscle; VDF, vascularized deep temporal fascial flap
SC
DTF flap. DTF, deep temporal fascia; STF, superficial temporal fascia; TM, temporal
13
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
ACCEPTED MANUSCRIPT Highlights
Endoscopic middle cranial fossa reconstruction via a subtemporal keyhole for repairing
RI PT
cerebrospinal leakage is proposed.
A vascularized deep temporal fascial flap is harvested through three small skin incisions under
SC
endoscopic view.
A 30-degree endoscope well visualizes bone defects on the middle cranial fossa via a subtemporal
M AN U
keyhole.
AC C
EP
TE D
Temporal bone defects are adequately overlaid by the vascularized deep temporal fascial flap.
1
S1878-8750(17)31454-7
DOI:
10.1016/j.wneu.2017.08.153
Reference:
WNEU 6403
To appear in:
World Neurosurgery
Received Date: 30 April 2017 Revised Date:
22 August 2017
Accepted Date: 23 August 2017
Please cite this article as: Komatsu F, Imai M, Hirayama A, Hayashi N, Oda S, Shimoda M, Matsumae M, Endoscopic middle cranial fossa reconstruction via a subtemporal keyhole: A technical note, World Neurosurgery (2017), doi: 10.1016/j.wneu.2017.08.153. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Komatsu et al.
ACCEPTED MANUSCRIPT
Endoscopic middle cranial fossa reconstruction via a subtemporal keyhole: A technical note
RI PT
Fuminari Komatsu, M.D., Ph.D.1, Masaaki Imai, M.D., Ph.D.1, Akihiro Hirayama, M.D., Ph.D.1, Naokazu Hayashi, M.D., Ph.D.1, Shinri Oda, M.D., Ph.D.1, Masami Shimoda, M.D., Ph.D.1, and Mitsunori Matsumae, M.D., D.M.Sc.2
Department of Neurosurgery, Tokai University Hachioji Hospital, Tokyo, Japan
2
Department of Neurosurgery, Tokai University School of Medicine, Kanagawa, Japan
M AN U
SC
1
Corresponding author: Fuminari Komatsu
Department of Neurosurgery, Tokai University Hachioji Hospital
TE D
1838 Ishikawa-machi, Hachioji, Tokyo, 192-0032, Japan E-mail: [email protected]
EP
Tel: +81 42-639-1111, Fax: +81 42-639-1112
AC C
Key words: endoscopy, minimally invasive surgery, skull base
Abbreviations list:
CSF, cerebrospinal fluid; CT, computed tomography; DTF, deep temporal fascia; IAM, internal acoustic meatus; MCF, middle cranial fossa; MR, magnetic resonance; STF, superficial temporal fascia; TM, temporal muscle; VDF, vascularized deep temporal fascial flap
1
Komatsu et al.
ACCEPTED MANUSCRIPT
Abstract Background Skull base reconstruction is an essential technique for repairing cerebrospinal fluid (CSF)
RI PT
leakage. A reliable method for middle cranial fossa (MCF) reconstruction with minimal invasiveness has not been reported. An initial case of endoscopic MCF reconstruction via a subtemporal keyhole is described. Case description
SC
A 57-year-old man developed severe meningitis and was diagnosed with spontaneous CSF leakage from bone defects on the tegmen tympani. Endoscopic MCF reconstruction via a
M AN U
subtemporal keyhole was carried out. Three skin incisions, including one subtemporal incision for a subtemporal keyhole and two temporal line incisions on the superior temporal line, were made, and a 0-degree endoscope was introduced into the subcutaneous space. The deep temporal fascia (DTF) was bluntly dissected and separated from both the superficial
TE D
temporal fascia and temporal muscle, and the DTF was incised to shape a pedicled flap under endoscopic view. Blood supply to the pedicled DTF flap was confirmed with indocyanine green angiography. A subtemporal keyhole was then made, and a 30-degree endoscope was used to explore the extradural space of the MCF floor, visualizing the bone
EP
defects on the tegmen tympani well. The vascularized DTF flap passed easily through the subtemporal keyhole and adequately overlaid the bone defects. The patient’s postoperative
AC C
course was uneventful, and CSF leakage disappeared without mastication problems. Conclusions
This purely endoscopic technique using a vascularized DTF flap provided reliable MCF reconstruction through a subtemporal keyhole. This technique is also expected to be applicable for MCF reconstruction after subtemporal keyhole surgery for skull base tumors.
2
Komatsu et al.
ACCEPTED MANUSCRIPT
Introduction Reconstruction of the skull base is an essential technique to repair cerebrospinal fluid (CSF) leakage attributed to spontaneous, post-traumatic, and postoperative conditions. Endoscopic
RI PT
endonasal surgery established minimally invasive reconstruction methods using the vascularized septal mucosal flap for CSF leakage from the anterior midline skull base, and these methods have been widely accepted for postoperative skull base reconstruction
following surgery for anterior midline skull base tumors, contributing to the development of
SC
endoscopic endonasal skull base surgery.1-4
On the other hand, excellent results of transcranial keyhole surgery for tumors have been
M AN U
reported so far,5, 6 but skull base reconstruction through a keyhole, especially subtemporal keyhole surgery to the middle cranial fossa (MCF), has only been discussed. Therefore, we previously investigated a novel reconstruction technique in a cadaver study and reported the potential advantages of endoscopic subtemporal MCF reconstruction using the deep
TE D
temporal fascia (DTF) (Fig. 1).7 The newly developed endoscopic technique is able to harvest a vascularized DTF flap, to allow access to the whole surface of the MCF floor, and to apply the vascularized DTF flap on the MCF via a subtemporal keyhole with minimal invasiveness. The nuances of and initial clinical experience with endoscopic subtemporal
EP
MCF reconstruction are presented.
AC C
Case description
A 57-year-old man developed severe meningitis with otorrhea and aural fullness. He had no history of head injury or otolaryngological diseases, and his body mass index was 23.0 kg/m2, indicating that he was not obese. Computed tomography (CT) and 3-dimensional CT revealed effusion in the left tympanic cavity and mastoid air cells (Fig. 2A). A group of small temporal bone defects, each with a diameter of approximately 2 mm, and slight pneumocephalus around the bone defects were seen on the tegmen tympani (Fig. 2B, C). Another bone defect, which was 3.5 mm in diameter and apart from the pneumocephalus,
3
Komatsu et al.
ACCEPTED MANUSCRIPT
was observed lateral to the groove for the greater superficial petrosal nerve (Fig. 2C). Magnetic resonance (MR) cisternography did not show any encephalocele. The clinical diagnosis was spontaneous CSF leakage from the bone defects on the tegmen tympani.
RI PT
Endoscopic subtemporal MCF reconstruction was carried out (Video 1). The institutional ethics committee approved this approach, and informed consent was obtained from the
patient. After insertion of the spinal drainage, the head was fixed so that the sagittal plane was parallel to the ground, and three skin incisions, including one subtemporal incision for a
SC
subtemporal keyhole and two temporal line incisions, were made. The anterior temporal line incision was located 2.0 cm anterior to the vertebral line on the zygomatic root, and the
M AN U
anterior and posterior temporal line incisions were 4.0 cm apart on the superior temporal line (Fig. 1A). A 4-mm 0-degree endoscope and a dissector were inserted from one temporal line incision, and the subcutaneous space was explored with blunt soft tissue dissection. As the dissection proceeded, an assistant elevated the cutaneous tissue using
TE D
other dissectors through another temporal line and/or subtemporal incisions to create working space (Fig. 3A). The DTF was separated from the superficial temporal fascia (STF), and then the DTF was elevated from the temporal muscle (Fig. 3B). Thus, the DTF was separated from both the STF and temporal muscle. Furthermore, the DTF was incised,
EP
shaping the pedicled DTF flap attached on the upper rim of the zygomatic arch (Fig. 3C, D). Blood supply from the middle temporal artery to the harvested DTF flap was shown by
AC C
indocyanine green angiography under microscopy (Fig. 3E). After harvesting the DTF flap, a subtemporal keyhole was placed after splitting of the temporal muscle along the subtemporal incision just above the zygomatic root. A 4-mm 30-degree endoscope was advanced into the extradural space of the MCF with elevation of the temporal dura mater to inspect the MCF floor. The groove for the greater superficial petrosal nerve was not exposed. The angled endoscope provided good visualization of the irregular surface of the MCF floor and detected the bone defects on the tegmen tympani and lateral to the groove for the greater superficial petrosal nerve (Fig. 3F, G). The bone defects on the tegmen
4
Komatsu et al.
ACCEPTED MANUSCRIPT
tympani were covered by membranous tissue. No obvious dural tear was observed on the temporal dura mater. It was impossible to distinguish which bone defect was responsible for the CSF leakage. The vascularized DTF flap was applied on the MCF floor through the
RI PT
subtemporal keyhole, and all temporal bone defects were adequately overlaid by the vascularized DTF flap and then fixed by fibrin glue (Fig. 3H). Rigid reconstruction was not performed because of the small bone defects. The subtemporal keyhole was closed with
care to preserve the blood supply to the DTF flap. Surgical time was 3.5 hours. The spinal
SC
drainage was removed immediately after the operation. The patient’s postoperative course was uneventful. CSF leakage and the effusion in the tympanic cavity on CT disappeared
M AN U
postoperatively (Fig. 2D). Gadolinium-enhanced MR imaging showed the DTF flap on the MCF floor (Fig 2E). An audiogram showed no conductive hearing loss. No signs of intracranial hypertension, such as papilledema, elevated opening pressure on lumbar puncture, and empty sella on MR imaging, were seen postoperatively. The patient had no
Discussion
TE D
difficulties with mastication. No recurrence was observed for 18 months.
Vascularized pedicle tissue has been recommended for skull base reconstruction because it
EP
significantly decreases the incidence of CSF leakage,1, 2, 8, 9 and the vascularized temporal
muscle flap has been commonly used for MCF reconstruction.10, 11 Although a temporal
AC C
muscle flap is effective to repair CSF leakage from the MCF, postoperative pain, mastication problems, trismus, and poor cosmetic results continue.11, 12 In addition, massive and bulky temporal muscle cannot be passed through the subtemporal keyhole, and rotational flexibility to temporal bone defects is limited. Therefore, a temporal muscle flap has not been used for subtemporal keyhole surgery. Novel endoscopic technique enables harvesting of the vascularized DTF flap from three small skin incisions with preservation of the temporal muscle, and it overcomes the disadvantages of the temporal muscle flap. The DTF anatomically receives its blood supply
5
Komatsu et al.
ACCEPTED MANUSCRIPT
from the middle temporal artery,7, 13, 14 and a robust blood supply to the DTF flap was confirmed by indocyanine green angiography. Regarding endoscopic manipulation in the MCF, a 30-degree endoscope provided good visualization of the irregular surface of the
RI PT
MCF floor even behind corners, and it detected temporal bone defects precisely with superb magnification. The thin but durable DTF flap had a small volume of tissue, and it therefore passed easily through the subtemporal keyhole. The DTF flap had a narrow pedicle, a long arc of rotation, and distant reach, contributing to coverage of a large surface on the MCF at
SC
an arbitrary location even under endoscopy.7 Rigid reconstruction using autograft bone or synthetic material was not performed in the present case because of the small bone defects,
M AN U
but it would be technically possible if needed. The CSF leakage from the temporal bone defects was successfully repaired, and preservation of the temporal muscle contributed to no mastication problems and excellent cosmetic results.
Potential complications include injury of the internal carotid artery in the carotid canal.
TE D
Endoscopic manipulation in the MCF may bring the risks of carotid injury in some cases of osseous deficiency on the petrous internal carotid artery. Pre-operative evaluation of neuroimages and careful identification using anatomical landmarks and navigation are mandatory.
hemostatic agents.
EP
In contrast, venous bleeding from the venous system would be properly controlled by
The risk of facial nerve palsy with this technique is also a potential concern in two phases.
AC C
First, the frontal branch of the facial nerve must be carefully protected during the harvest of the DTF flap. The anterior temporal line incision should not extend anteriorly, and dissection must be kept within the appropriate layers, to avoid the running course of the frontal branch of the facial nerve. Second, the greater superficial petrosal nerve must be preserved during extradural dissection of the MCF. Facial nerve monitoring would contribute to avoiding this complication. Although this is a case report and the patient still requires a long period of follow-up, this technique appears to be an effective, safe, and reliable approach for MCF reconstruction
6
Komatsu et al.
ACCEPTED MANUSCRIPT
with minimal invasiveness. This technique is also expected to be useful in MCF reconstruction after purely endoscopic or endoscope-assisted subtemporal keyhole surgery
RI PT
for skull base tumors.15, 16
Conclusions
An initial case of endoscopic MCF reconstruction by subtemporal keyhole surgery was
described. The vascularized DTF flap was flexible, long, and large enough to overlay bone
SC
defects on the MCF, overcoming the problems related to temporal muscle. This endoscopic
M AN U
technique could be a valid alternative for MCF reconstruction.
Acknowledgements
The authors greatly appreciate the assistance of Professor Manfred Tschabitscher of Brescia
TE D
University, Italy, for teaching the endoscopic anatomy related to this surgical technique, and Dr. Mika Komatsu of Ohta Neurosurgical Clinic, Japan, for cooperation with previous
AC C
Funding
EP
anatomical studies and cordial advice regarding this study.
This study did not receive any specific grants from funding agencies in the public, commercial, or not-for-profit sectors.
Declaration of interest Conflicts of interest: none
Role of the funding source Not applicable. 7
Komatsu et al.
ACCEPTED MANUSCRIPT
References 1.
Hadad G, Bassagasteguy L, Carrau RL, Mataza JC, Kassam A, Snyderman CH, et al.
RI PT
A novel reconstructive technique after endoscopic expanded endonasal approaches: vascular pedicle nasoseptal flap. Laryngoscope. 2006;116:1882-1886. 2.
Kassam AB, Thomas A, Carrau RL, Snyderman CH, Vescan A, Prevedello D, et al.
SC
Endoscopic reconstruction of the cranial base using a pedicled nasoseptal flap.
3.
M AN U
Neurosurgery. 2008;63:ONS44-52; discussion ONS-53.
Thorp BD, Sreenath SB, Ebert CS, Zanation AM. Endoscopic skull base reconstruction: a review and clinical case series of 152 vascularized flaps used for surgical skull base defects in the setting of intraoperative cerebrospinal fluid leak.
4.
TE D
Neurosurg Focus. 2014;37:E4.
Horiguchi K, Nishioka H, Fukuhara N, Yamaguchi-Okada M, Yamada S. A new
EP
multilayer reconstruction using nasal septal flap combined with fascia graft dural suturing for high-flow cerebrospinal fluid leak after endoscopic endonasal surgery.
5.
AC C
Neurosurg Rev. 2016;39:419-427. Taniguchi M, Perneczky A. Subtemporal keyhole approach to the suprasellar and petroclival region: microanatomic considerations and clinical application.
Neurosurgery. 1997;41:592-601. 6.
Berhouma M, Jacquesson T, Jouanneau E. The fully endoscopic supraorbital transeyebrow keyhole approach to the anterior and middle skull base. Acta Neurochir (Wien). 2011;153:1949-1954. 8
Komatsu et al.
ACCEPTED MANUSCRIPT
7.
Komatsu M, Komatsu F, Di Ieva A, Inoue T, Tschabitscher M. Endoscopic reconstruction of the middle cranial fossa through a subtemporal keyhole using a
RI PT
pedicled deep temporal fascial flap: a cadaveric study. Neurosurgery. 2012;70:157161; discussion 162. 8.
Fattahi T, Dipasquale J. Utility of the pericranial flap in frontal sinus and anterior
Taha M, Carroll T, McMahon J. Vascularized temporoparietal fascial flap for the
M AN U
9.
SC
cranial fossa trauma. Int J Oral Maxillofac Surg. 2009;38:1263-1267.
treatment of a traumatic cerebrospinal fluid fistula in the middle cranial fossa. Technical note. J Neurosurg. 2009;111:393-395. 10.
Cantu G, Solero CL, Riccio S, Colombo S, Pompilio M, Aboh IV, et al. Surgery for
2010;20:55-60.
Gonen L, Handzel O, Shimony N, Fliss DM, Margalit N. Surgical management of
EP
11.
TE D
malignant maxillary tumors involving the middle cranial fossa. Skull Base.
spontaneous cerebrospinal fluid leakage through temporal bone defects--case series
12.
AC C
and review of the literature. Neurosurg Rev. 2016;39:141-150; discussion 150. Olson KL, Manolidis S. The pedicled superficial temporalis fascial flap: a new
method for reconstruction in otologic surgery. Otolaryngol Head Neck Surg. 2002;126:538-547.
13.
Krayenbuhl N, Isolan GR, Hafez A, Yasargil MG. The relationship of the frontotemporal branches of the facial nerve to the fascias of the temporal region: a
9
Komatsu et al.
ACCEPTED MANUSCRIPT
literature review applied to practical anatomical dissection. Neurosurg Rev. 2007;30:8-15. Beheiry EE, Abdel-Hamid FA. An anatomical study of the temporal fascia and
RI PT
14.
related temporal pads of fat. Plast Reconstr Surg. 2007;119:136-144. 15.
Komatsu F, Komatsu M, Di Ieva A, Tschabitscher M. Endoscopic extradural
SC
subtemporal approach to lateral and central skull base: a cadaveric study. World
Komatsu F, Komatsu M, Di Ieva A, Tschabitscher M. Endoscopic approaches to the trigeminal nerve and clinical consideration for trigeminal schwannomas: a cadaveric
EP
TE D
study. J Neurosurg. 2012;117:690-696.
AC C
16.
M AN U
Neurosurg. 2013;80:591-597.
10
Komatsu et al.
ACCEPTED MANUSCRIPT
Figure Legends Figure 1. Outline of the endoscopic subtemporal MCF reconstruction. A, The design of the skin
RI PT
incisions is shown. The green line indicates the subtemporal incision for subtemporal keyhole craniotomy, and the two yellow lines mark the temporal line incisions used for
endoscopic manipulation to harvest a pedicled DTF flap. B, Endoscopic harvest of the DTF flap is illustrated. The operator uses one temporal line incision to introduce the endoscope
SC
and a dissector (asterisk) to harvest the DTF. The assistant introduces another dissector (double asterisks) via another temporal line incision and creates a working space with skin
M AN U
elevation. The DTF is incised to form the pedicled flap with subcutaneous manipulation under endoscopy. C, Endoscopic exploration of the MCF is shown. The endoscope is introduced into the extradural space of the MCF floor through the subtemporal keyhole, and it illuminates the bone defect (red dimple) on the tegmen tympani. The pedicled DTF flap is
on the bone defect.
Figure 2.
TE D
reflected through the subtemporal incision. D, The pedicled DTF flap is adequately overlaid
EP
Pre-(A, B, C) and post-(D, E) operative neuro-images of the case presented. A, CT shows an effusion in the left tympanic cavity and mastoid air cells (yellow arrow). B, Slight
AC C
pneumocephalus around the left tegmen tympani is shown (white arrow). C, 3D-CT indicates a group of small bone defects (green dotted circle) on the left tegmen tympani and another bone defect (blue arrow) lateral to the groove for the greater superficial petrosal nerve. D, Postoperative CT shows disappearance of the effusion in the left tympanic cavity and mastoid air cells. E, Coronal view of gadolinium-enhanced MR image demonstrates the DTF flap (red arrow heads) overlaid on the MCF floor. IAM, internal acoustic meatus.
Figure 3.
11
Komatsu et al.
ACCEPTED MANUSCRIPT
Intra-operative findings of the case presented. Endoscopic harvest of a vascularized DTF flap is shown in A, B, C, and D. A, The operator inserts a 4-mm 0-degree endoscope through one temporal incision, while an assistant elevates the cutaneous tissue by dissectors
RI PT
(asterisks) through another temporal line and subtemporal incisions to create working space. The DTF is separated from the STF. B, The DTF is elevated from the temporal muscle. C, The DTF is incised to form the DTF flap. D, The harvested DTF flap measures 7.0 cm × 1.5 cm × 4.0 cm (length × width at base × width at distal end). E, Indocyanine green
SC
angiography of the harvested DTF flap under microscopy. The blood supply from the middle temporal artery to the harvested DTF flap is depicted by indocyanine green
M AN U
angiography under microscopy (white arrow). Endoscopic views of the extradural MCF floor are shown in F, G, and H. F, G, A 4-mm 30-degree endoscope is advanced into the extradural space of the MCF with elevation of the temporal dura mater, and the bone defects on the tegmen tympani (green dotted circle) (G) and lateral to the groove for the greater
TE D
superficial petrosal nerve (blue arrow) (F) are detected. The bone defects on the tegmen tympani are covered by membranous tissue. H, All temporal bone defects are adequately overlaid by the vascularized DTF flap. DTF, deep temporal fascia; STF, superficial
Video legends
EP
temporal fascia; TM, temporal muscle; VDF, vascularized deep temporal fascial flap
AC C
Endoscopic harvest of a vascularized DTF flap. After making three skin incisions, including a subtemporal and two other small incisions on the superior temporal line, a 4mm 0-degree endoscope and instruments are inserted into the subcutaneous layers. The STF and DTF are bluntly separated, and the space between the STF and DTF is connected through the three skin incisions. Then, the DTF is elevated from the temporal muscle via the two temporal line incisions. Thus, the DTF is separated from both the STF and temporal muscle. Furthermore, the DTF is incised, shaping the pedicled DTF flap attached on the upper rim of the zygomatic arch.
12
Komatsu et al.
ACCEPTED MANUSCRIPT
The blood supply from the middle temporal artery to the harvested DTF flap is depicted by indocyanine green angiography under microscopy. Endoscopic reconstruction of the MCF floor. A 30-degree endoscope is advanced into the
RI PT
extradural space of the MCF. First, a bone defect lateral to the groove for the greater superficial petrosal nerve (blue arrow) comes into view. Then, a group of bone defects on the tegmen tympani (green dotted circle) are identified, and these are covered with
membranous tissue. All temporal bone defects are adequately overlaid by the vascularized
AC C
EP
TE D
M AN U
muscle; VDF, vascularized deep temporal fascial flap
SC
DTF flap. DTF, deep temporal fascia; STF, superficial temporal fascia; TM, temporal
13
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
ACCEPTED MANUSCRIPT Highlights
Endoscopic middle cranial fossa reconstruction via a subtemporal keyhole for repairing
RI PT
cerebrospinal leakage is proposed.
A vascularized deep temporal fascial flap is harvested through three small skin incisions under
SC
endoscopic view.
A 30-degree endoscope well visualizes bone defects on the middle cranial fossa via a subtemporal
M AN U
keyhole.
AC C
EP
TE D
Temporal bone defects are adequately overlaid by the vascularized deep temporal fascial flap.
1
