Results
Patient Demographics
Twenty-three patients underwent surgical repair of tegmen defects during the study period. A summary of the preoperative demographics is shown in Table 1. The average age of the patients was 55.1 ± 12.5 years. There was no sex predilection, with nearly equal distribution between males (11) and females (12). The patients reviewed were generally overweight, with an average BMI of 33.2 ± 7.2 kg/m. In fact, only 4 patients (17%) had a BMI <25 kg/m, and 65% (15 of 23) were obese (BMI > 30 kg/m).
Five patients (22%) had a history of cranial trauma that was suspicious for an inciting event for the development of a tegmen defect and CSF fistula. In 4 patients (17%), there was a history of meningitis. All 23 patients presented with hearing loss in the ear ipsilateral to the tegmen defect to be repaired. The presenting symptom in 19 patients (83%) was CSF otorrhea. In all but 2 of these patients, the CSF otorrhea occurred after placement of the myringotomy tubes for middle ear fullness and fluid. Other presenting symptoms were temporal meningoencephalocele (discovered intraoperatively during a prior otological procedure, 2 patients), an episode of acute otitis media and mastoiditis (1 patient), and pulsatile tinnitus (1 patient). The tegmen defect repairs occurred nearly equally in the right (10 patients) and left (13 patients) temporal bones. However, there were bilateral defects in 10 of the patients (43%). An empty sella was noted on preoperative MRI in 4 patients (17%).
Operative Details
The intraoperative findings are summarized in Table 2. The average preoperative OP obtained during lumbar puncture under general anesthesia was 21.8 ± 6.0 cm H2O. A lumbar drain was placed preoperatively in every patient, with the exception of 2 in whom difficulty with passing the catheter prevented its use. Both of these patients had had previous lumbar spinal fusion procedures. The lumbar drain was maintained throughout the surgical procedure and was usually removed on postoperative Day 3. In 22 patients (96%), a synthetic dural inlay was used for intradural repair. The one exception was a patient with significant intradural adhesions due to chronic inflammation and very prominent temporal veins. An intradural graft was not placed in this case given concerns that venous drainage might be disrupted. Extradurally, autologous tissue, either pericranium or temporalis fascia, was used to cover the osseous cranial base defect in 20 patients (87%). In 11 of them (48%), a portion of the temporal craniotomy bone was used to cover exposed middle ear ossicles prior to the placement of autologous graft. In 2 patients (9%), allograft was used both intradurally and extradurally. A single patient had only autologous bone used for extradural repair since a significant dural defect was not identified, and this patient only presented with pulsatile tinnitus and not otorrhea.
Intracranial Hypertension Management
Our experience with intracranial hypertension management in this population is summarized in Table 3. Ten patients in the study had a preoperative OP ≥ 20 cm H2O, with 7 patients demonstrating an OP ≥ 25 cm H2O. Long-term CSF diversion in the form of VP shunting was suggested to 8 patients. Three of them refused shunts. A recurrent leak developed in 1 patient within a week but was managed with aggressive lumbar drainage; despite the recurrence, the patient continues to refuse a VP shunt and remains under close observation. One of the patients who underwent shunting had an OP of 12 cm H2O, but because of the presence of a high-volume leak and a BMI of 40.4 kg/m, a VP shunt was placed. In 3 others with an OP ≥ 20 cm H2O, VP shunt placement was deferred. This was the case in 2 patients with a history of cranial trauma that might have been the cause of the tegmen defect rather than intracranial hypertension. The third patient under observation without a VP shunt had a normal BMI, a low-volume leak, and no other radiographic signs of intracranial hypertension (that is, bilateral tegmen defects or empty sella).
Patient Outcomes
During an average follow-up of 10.4 ± 6.4 months (range 3–26 months), operative repair prevented further CSF leaks or recurrent symptoms in 22 patients (96%). The 1 patient with transient residual postoperative CSF otorrhea was successfully treated with the replacement of a lumbar drain and aggressive drainage for 7 days. With 19 months of follow-up, that patient continues to be free of any further symptoms of CSF leakage. Unfortunately, he did require ossicular chain reconstruction 5 months postoperatively because the tegmen repair was contacting the middle ear structures despite being covered with a segment of the temporal craniotomy bone. In this case, the head of the incus became fused with the overlying bone graft. Additional complications (Table 4) included 1 case each of local wound infection, meningitis, deep vein thrombosis, and postoperative seizures. These last 3 complications all occurred in 1 patient who had a number of preoperative medical comorbidities, including a BMI of 40.4 kg/m and Type 2 diabetes mellitus.