Abstract
Purpose
To explore the outcomes of lateral attic wall (LAW) reconstruction using autogenous mastoid cortical bone in cases with poorly developed zygomatic root cells and/or a low tegmen or with significant anterior or lateral sigmoid sinus in tympanomastoid surgery.
Material and methods
Thirty-five ears with chronic suppurative otitis media, all of them either with poorly developed zygomatic root cells and/or a low tegmen (26/35 ears), or with significant anterior or lateral sigmoid sinus (9/35 ears), were included. LAWs were removed temporarily to offer exposure of the attic; after removal of the pathological conditions in the attic and the mastoid, LAW was reconstructed using autogenous mastoid cortical bone. The condition of the reconstructed LAW and tympanomastoid aeration was evaluated by computed tomographic scan or/and otoendoscopy.
Results
The pathological conditions in the attic, the antrum, and the mastoid could be removed with safety in all cases; no serious complications occurred, the new canal appeared to be of normal size and shape, and no dislocation or necrosis of the repaired part was noted. Most of the cases had no significant attic retraction and kept good tympanomastoid aeration postoperatively.
Conclusion
The reconstruction of LAW is especially suited to the cases in our study, and the reconstructed LAW can produce an almost normal anatomical external auditory canal, prevent the formation of attic retraction, and restore the mastoid cavity aeration in most of the cases.
1
Introduction
Excellent exposure of the attic can decrease the risk of injury to the facial nerve and the dura and reduce the residence of pathological conditions during tympanomastoid surgery, and an intact attic wall can prevent retraction pocket formation . The combined presence of a normal-sized ear canal protected by a solid bony wall and a tympanic membrane well placed in its normal position seems to provide the ideal basis for a stable hygienic condition of the ear . It would be also ideal if an aerated mastoid cavity with a pressure-regulation function for middle ear was restored even after mastoidectomy , but in cases either with poorly-developed zygomatic root cells and/or a low-lying dura, or with significant anterior or lateral sigmoid sinus, canal wall up (CWU) surgery is a significantly unsuitable technique to them. To deal with these conditions, canal wall down (CWD) surgery is the single choice, which leaves a large opened mastoid cavity. Since 2005, we have dealt with these cases by temporary removal of the attic wall, offering exposure by CWD surgery for pathological conditions extirpation, followed by reconstruction of the canal wall defect using autologenous mastoid cortical bone at the first-stage operation. The outcome of LAW reconstruction on the prevention of retraction pockets and the indications for the technique are discussed.
2
Patients and methods
2.1
Patients and indications
From January 2005 to July 2008, the reconstruction of the LAW using bone plate was carried out in 35 ears of 32 inpatients with chronic otitis media during the first-stage operation. All of them had poorly developed zygomatic root cells and/or a low tegmen (26/35 ears) or had significant anterior or lateral sigmoid sinus (9/35 ears), and the pathological conditions had extended to the mastoid. The cases with small cholesteatoma which was limited to the attic were not included because they could be treated only by sectum plasty , and the cases with extensive destruction of the posterior canal wall and mastoid cortex were also not the indications, or the cases with both low tegmen and significant anterior or lateral sigmoid sinus simultaneously were also excluded, as CWD mastoidectomy could be fitted to those cases. No evidence was shown the obstruction of the Eustachian tube by Valsalva maneuver. The patients consisted of 14 women and 18 men, 14 to 67 years of age, with an average age of 36.2 years. The protocol was approved by Institutional Committee of the Beijing Institute of Otolaryngology.
2.2
Routine high-resolution computed tomography scanning
Computed tomographic (CT) images were acquired in the axial, coronal, and sagittal planes using the Philips Brilliance 64 CT scanner. The imaging parameters were as follows: voltage, 120 Kv; current, 200 mA; matrix, 512 × 512; and reconstructing section thickness, 1 mm. These images were reconstructed using a bone algorithm. All CT images were reviewed on a PACS system (Huahai Medical Info-Tech Co, Ltd, Beijing, China) on the bone window setting (window width, 4000 HU, and window level, 700 HU).
2.3
Surgical technique
A traditional postauricular skin incision was followed by the elevation of anteriorly based dermal and musculoperiosteal flaps; the mastoid cortex was widely exposed. Bone plate was obtained by drilling the mastoid cortical bone and, if needed, from the squama of the temporal bone. The bone plate would be sculpted into a floodgate-like shelf, which was used as the repair material for the LAW. Then, a traditional atticotomy combination with mastoidectomy was performed while the posterior wall of the external auditory canal was left intact. After removal of the LAW, the epitympanic space, the supratubal recess, the mastoid antrum, the facial nerve, and the stapes could be visualized excellently; the pathological conditions, such as cholesteatoma or granulation, which surrounded the ossicular bone or located on the surface of the facial nerve or on the horizontal semicircular canal could be directly removed, and the low dura or the lateral or anterior sigmoid sinus injury could be avoided. The pathological conditions extending to the mastoid cavity were also removed. Then, a reconstruction procedure similar to that of the retrograde mastoidectomy with some modifications was taken. A 1- to 2-mm diamond burr was used to create a groove on the anterior root of the attic wall and the superioposterior canal wall, respectively. The groove was 1 to 2 mm wide and 2 mm deep and oriented parallel to the inferior canal to avoid torsion of the graft. Medially, the groove and subsequent reconstruction extended down and just posterior to the anterior malleolar spine and ligament, so it approximated well to the cut edge of the malleus precisely. The floodgate-like bone shelf was then fixed into the bilateral grooves ( Fig. 1 ). When the superioposterior canal wall was very thin due to a combination of the canaloplasty and subsequent mastoidectomy, instead of drilling a groove in the superioposterior canal wall, a groove was drilled on the edge of the shelf ( Fig. 2 ), which faced the posterior canal wall, and the shelf was inserted between the anterior root of the attic wall and the superioposterior canal wall. Then, the different kinds of the tympanoplasty were performed; the canal was packed with cotton wicks soaked with antibiotic ointment. The postauricular musculoperiosteal flap was repositioned.
The packing was removed 14 days later, and the condition of the canal wall was observed by otoendoscopy. Hearing assessment was performed 3 months postoperatively and the results would be discussed in another report. Postoperative CT scanning would be performed after 9 to 12 months if there was any evidence of residual or recurrent cholesteatoma. The conditions of the reconstructed LAW and the tympanomastoid aeration were evaluated by CT scanning. When air space was found to form throughout the entire mastoid cavity and tympanic cavity, it was judged as good recovery of tympanomastoid; otherwise, it was defined as poor recovery when the air space was seen only in tympanic cavity.
Second-look surgery was only performed in those cases where a suspicious mass existed in the epitympanium or mastoid cavity on CT imaging, or when a white mass expanded out from the sinus tympani when viewed by otoendoscopy. Sometimes, magnetic resonance imaging was needed to distinguish scar tissue formation from recurrent cholesteatoma in the mastoid cavity.
The mean follow-up time was 42 months (range, 20–66 months).
2
Patients and methods
2.1
Patients and indications
From January 2005 to July 2008, the reconstruction of the LAW using bone plate was carried out in 35 ears of 32 inpatients with chronic otitis media during the first-stage operation. All of them had poorly developed zygomatic root cells and/or a low tegmen (26/35 ears) or had significant anterior or lateral sigmoid sinus (9/35 ears), and the pathological conditions had extended to the mastoid. The cases with small cholesteatoma which was limited to the attic were not included because they could be treated only by sectum plasty , and the cases with extensive destruction of the posterior canal wall and mastoid cortex were also not the indications, or the cases with both low tegmen and significant anterior or lateral sigmoid sinus simultaneously were also excluded, as CWD mastoidectomy could be fitted to those cases. No evidence was shown the obstruction of the Eustachian tube by Valsalva maneuver. The patients consisted of 14 women and 18 men, 14 to 67 years of age, with an average age of 36.2 years. The protocol was approved by Institutional Committee of the Beijing Institute of Otolaryngology.
2.2
Routine high-resolution computed tomography scanning
Computed tomographic (CT) images were acquired in the axial, coronal, and sagittal planes using the Philips Brilliance 64 CT scanner. The imaging parameters were as follows: voltage, 120 Kv; current, 200 mA; matrix, 512 × 512; and reconstructing section thickness, 1 mm. These images were reconstructed using a bone algorithm. All CT images were reviewed on a PACS system (Huahai Medical Info-Tech Co, Ltd, Beijing, China) on the bone window setting (window width, 4000 HU, and window level, 700 HU).
2.3
Surgical technique
A traditional postauricular skin incision was followed by the elevation of anteriorly based dermal and musculoperiosteal flaps; the mastoid cortex was widely exposed. Bone plate was obtained by drilling the mastoid cortical bone and, if needed, from the squama of the temporal bone. The bone plate would be sculpted into a floodgate-like shelf, which was used as the repair material for the LAW. Then, a traditional atticotomy combination with mastoidectomy was performed while the posterior wall of the external auditory canal was left intact. After removal of the LAW, the epitympanic space, the supratubal recess, the mastoid antrum, the facial nerve, and the stapes could be visualized excellently; the pathological conditions, such as cholesteatoma or granulation, which surrounded the ossicular bone or located on the surface of the facial nerve or on the horizontal semicircular canal could be directly removed, and the low dura or the lateral or anterior sigmoid sinus injury could be avoided. The pathological conditions extending to the mastoid cavity were also removed. Then, a reconstruction procedure similar to that of the retrograde mastoidectomy with some modifications was taken. A 1- to 2-mm diamond burr was used to create a groove on the anterior root of the attic wall and the superioposterior canal wall, respectively. The groove was 1 to 2 mm wide and 2 mm deep and oriented parallel to the inferior canal to avoid torsion of the graft. Medially, the groove and subsequent reconstruction extended down and just posterior to the anterior malleolar spine and ligament, so it approximated well to the cut edge of the malleus precisely. The floodgate-like bone shelf was then fixed into the bilateral grooves ( Fig. 1 ). When the superioposterior canal wall was very thin due to a combination of the canaloplasty and subsequent mastoidectomy, instead of drilling a groove in the superioposterior canal wall, a groove was drilled on the edge of the shelf ( Fig. 2 ), which faced the posterior canal wall, and the shelf was inserted between the anterior root of the attic wall and the superioposterior canal wall. Then, the different kinds of the tympanoplasty were performed; the canal was packed with cotton wicks soaked with antibiotic ointment. The postauricular musculoperiosteal flap was repositioned.
