Although considered histologically benign, surgical management of JPs is challenging due to their infiltrative nature and proximity to important neurovascular structures. The Fisch class A and B tumors can be treated surgically by skillful otologists with standard approaches with almost no complications, preserving the FN and inner ear function and offering the patient a complete cure15, 18. Management of the Fisch class C and D tumors has remained controversial, and there are still various opinions, such as surgery, radiotherapy or wait-and-scan3, 6, 19–24. This study retrospectively analyzed the clinical efficacy of surgical treatment of Fisch class C and D tumors in our institution in the past 10 years following application of our modified surgical techniques and concluded that surgical treatment of JPs is a safe and effective strategy, especially for C1 and C2 tumors.
In the case of surgical management of JPs, IFTA-A, with permanent anterior rerouting of the FN and exposure of the intratemporal course of the ICA as described by Fisch in 1977, is considered the standard procedure. Due to permanent anterior FN transposition, the FN might lose most of its extrinsic vascularity, resulting in a certain degree of facial paralysis after surgery. Nevertheless, advances in neuroimaging, skull base techniques and modified surgical approaches have markedly reduced the incidence of FN dysfunction during the last two decades7–9, 11, 12, 25; however, a majority of surgeons still concern postoperative FN function. In this study, preoperatively, six patients (20.7%) had HB grade III-VI in classes C1 and C2, while nine (33.3%) had HB grade III-VI in classes C3 and D. Although there was no significant difference in FN function between the two groups, the incidence of facial paralysis in classes C3 and D was greater than that in classes C1 and C2 preoperatively. Thirty-four patients with normal FN function preoperatively and the epineurium were identified as intact intraoperatively in our study. They underwent tension-free FN anterior rerouting, and 31 cases (91.2%) achieved good facial nerve function (House-Brackmann grade I-II), which indicated that good FN function was achieved in more than 90% of patients who underwent tension-free FN anterior rerouting. Wang et al. reported a postoperative rate of new FN deficits of 51.7% in eighty-nine patients with Fisch class C or D JPs26. In a recent study, 185 patients with Fisch class C or D JPs were treated surgically by Prasad and colleagues, and forty-three (23.2%) new FN deficits (House-Brackmann grade III-VI) were observed as a consequence of FN mobilization in IFTA-A3. In the present study, 31 patients (91.2%) achieved good facial nerve function following the application of tension-free FN anterior rerouting. The tension-free FN anterior rerouting technique significantly reduced the incidence of new FN deficits.
In our clinical practice, achieving optimal exposure of the jugular foramen while minimizing the damage to neurovascular structures and obtaining proximal and distal exposures of the ICA are the key points. The management of FN plays an important role in exposure of the jugular foramen. FN management strategies are included in the fallopian bridge technique and the total or partial tension-free FN anterior rerouting technique, which are determined based on the extent of the lesion shown on temporal bone CT and MRI preoperatively. In the present study, most of the patients underwent tension-free FN anterior rerouting in cases of normal facial nerve function preoperatively, thereby reducing the incidence of FN dysfunction, and 31 patients (91.2%) achieved good facial nerve function postoperatively.
Given highly vascular tumors, heavy intraoperative bleeding frequently occurs during the removal of JPs. To reduce intraoperative bleeding, preoperative superselected embolization of the main feeding arteries of the tumor is routinely performed on patients with JPs. In addition, effectively controlling intraoperative bleeding from the inferior petrous sinus can provide a clearer surgical field and decrease the incidence of neurovascular structure damage. In the present study, we applied our modified technique, the sigmoid sinus tunnel packing and push packing technique, to control bleeding from the inferior petrous sinus11, which led to a mean blood loss of 502 ml.
Function preservation of LCNs is another key point that draws attention to the discussion of JP management options. The intrabulbar dissection technique was proposed in 2002 and was routinely applied to dissect tumors in our clinical practice as long as the tumor itself had not penetrated the medial wall of the jugular bulb or infiltrated the LCNs17. Prasad et al. noticed that the presence of intradural extension is usually associated with infiltration of the LCNs3. Thus, resection of early JPs (classes C1-C2), where the lateral aspect of the jugular bulb is involved and the medial wall is not infiltrated, makes preservation of the LCNs possible. Our investigation also revealed a lower incidence (3 cases, 10.3%) of LCN dysfunction in classes C1 and C2 and a greater incidence (11 cases, 40.7%) in classes C3 and D preoperatively. Furthermore, surgery resulted in newly developed LCN deficits in 14.3% of patients. In addition, conservative surgical management of JPs with targeted subtotal resection based on the extent and location of tumors yields lower new-onset LCNs19, 21, 27. Similar to other benign skull base tumors, the authors believe that tumor recurrence is likely related to the extent of resection. The more tumor is removed, the less likely the residual tumor28. Bacciu et al. demonstrated that class C1 and C2 tumors can be removed completely using IFTA-A with fewer LCN deficits29. Our results were consistent with a previous study, and GTR (100%) was able to achieve fewer postoperative new LCN deficits (4 cases, 13.8%) in classes C1 and C2. Therefore, radical excision is recommended for early-stage JPs to reduce the incidence rate of LCN deficits and prevent tumor recurrence instead of subtotal resection.
It has also been demonstrated that MR arteriography is not only useful to visualize the major feeding arteries of paragangliomas but is also helpful in the detection and characterization of paragangliomas30. Our study retrospectively reviewed the patient's preoperative MRA data and analyzed the correlation between the Fisch classification of tumors, intraoperative blood loss and the maximum cross-sectional area of intratumor blood vessels. We concluded that the advanced the tumor class, the more intraoperative blood loss and the greater the cross-sectional area of intratumor blood vessels. However, there was no significant correlation between the Fisch classification of tumors and the maximum cross-sectional area of intratumor blood vessels. It is well known that the Fisch classification is based on the relationship of the tumor location with the ICA and intracranial extension, rather than the size of the tumor. The Fisch classification of tumors was positively correlated with intraoperative blood loss, indicating more bleeding in advanced tumors, resulting in unclear surgical fields, less GTR and increased injury of neurovascular structures. Therefore, to reduce the incidence of perioperative complications and improve the GTR rate, we recommend early surgical intervention.
In recent years, radiotherapy has become popular as the first-line treatment for JPs due to its high tumor control and low morbidity compared with the surgical management of JPs5, 20, 31. Recently, Patel and colleagues reported a series of 40 cases with JPs treated by linear accelerator stereotactic radiosurgery20. Similar to the previous outcomes of the radiotherapy study, the authors did not classify tumors according to the Fisch classification but preferred to report them based on tumor sizes. Considering that the mean pretreatment volume size was 8.9 cm3 (range 3.8–13.1 cm3), most of them were probably small tumors (possibly even class B tympanomastoid paragangliomas according to the Fisch classification), which can be treated surgically by skillful otologists with standard approaches with almost no complications and achieve gross total tumor removal. With improvements in surgical techniques and perioperative management, the incidence of cranial nerve injury and serious complications caused by surgical treatment has gradually decreased. However, the unique complications of radiotherapy cannot be avoided, such as temporal bone necrosis, brain necrosis, secondary malignancy and pituitary/hypothalamic insufficiency20. The most significant effect of radiotherapy is related to radiation‑induced fibrosis with obliteration of the vascular supply and not to direct destruction of tumor cells. Thus, it is important to re‑emphasize that radiotherapy only achieves tumor control and not a cure. Jansen et al. noted that age of presentation was a risk factor for tumor growth, and 59 patients with JPs who underwent wait-and-scan with a median follow-up of 63.6 months showed that the age of presentation was an independent predictor of tumor growth and had a significant inverse correlation with growth rates: the younger the age of presentation was, the greater the growth rate6. It is essential to achieve cure rather than tumor control in those who have more than 30 years of life expectancy. If radiotherapy is considered in young patients, it also means life-long surveillance scans and the psychological burden caused by living with the knowledge of having a residual tumor. Long-term treatment (surgery, radiotherapy or a combined modality) outcomes of 93 Fisch class C and D tumors were evaluated by Jansen’s group in 2018. One independent predictor of treatment outcome was found: if treatment was delayed until tumor growth occurred, the chance of functional recovery was lower19. Taken together, we consider it important to make an early diagnosis and perform surgery as early as possible. As outlined above, although the management of JPs is challenging, we believe that surgical gross total resection of the tumor remains the mainstay of treatment of JPs.