71.2.1 Clinical Evaluation

The temporal profile of the headache in relation to the timing of the operation can help guide evaluation and provides clues to the underlying cause of the headache. Generally, serious causes of postoperative headache would occur during the acute period, less than 3 months after the operation. The differential diagnosis of acute and chronic postoperative headaches in patients undergoing surgery for VS is listed in Table 71‑1 .

The history should address the location, quality, frequency, and duration of the pain in addition to aggravating and alleviating factors. Two retrospective studies reported that VS headaches were most commonly localized to the occipitals. Literatur or neck region.s. Literatur Headaches may also localize to the frontal region, top of the head, or entire head,s. Literatur ^,​ s. Literatur ^,​ s. Literatur and have been reported to be both unilateral or bilateral.s. Literatur

The examination should focus on assessing the temporomandibular joint and muscles of mastication if a temporal craniotomy was performed, examining the scar for signs of infection or neuralgic pain at the site, assessing cervical range of motion, palpation of areas of emergences of cranial or spinal nerves, funduscopic examination for papilledema, and evaluating for neurologic dysfunction. Importantly, the initial evaluation should carefully rule out serious causes of postoperative headache.

Headache severity can be assessed in the clinical and research setting. Headache severity is most commonly assessed in the clinical setting via patient questionnaire, direct questioning, or estimated using a nonstandardized rating scale, either ordinal or visual analog.s. Literatur ^,​ s. Literatur ^,​ s. Literatur ^,​ s. Literatur ^,​ s. Literatur Several studies have retrospectively quantified headache severity by assigning a numerical value from review of medical records alone.s. Literatur ^,​ s. Literatur ^,​ s. Literatur ^,​ s. Literatur Standardized measures of headache severity have also been employed by a few authors. Carlson and colleagues used the Headache Disability Inventory (Fig. 71‑1 ) to assess the functional and emotional effects of headache on everyday life.s. Literatur This 25-item standardized measure of headache severity has been shown to have good internal reliability and content validity.s. Literatur ^,​ s. Literatur Other validated instruments have been developed to assess headache and pain in the context of other quality-of-life measures. The Penn Acoustic Neuroma Quality of Life Scale is a self-report questionnaire that includes seven domains, one of which assesses head pain in the form of a single question.s. Literatur Finally, a number of self-rated headache disability inventories exist but have not yet been employed in the VS literature, presenting an opportunity for future study. These include the Headache Impact Test (HIT),s. Literatur Headache Disability Questionnaire (HDQ),s. Literatur Burden of Migraine (BURMIG) questionnaire,s. Literatur and EUROLIGHT questionnaire.s. Literatur

71.2.2 Secondary Causes

In the acute period, serious causes should be considered and excluded. Intracranial hemorrhage (intraparenchymal or subdural) complicates VS surgery in less than 5% of patientss. Literatur and may present with headache and change in level of awareness or consciousness with or without focal neurologic symptoms. Cerebrospinal fluid (CSF) leak is a common complication of VS surgery, but is usually associated with CSF rhinorrhea and generally not spontaneous intracranial hypotension.s. Literatur However, spontaneous intracranial hypotension with postural headache due to a spinal source has been described in patients postoperatively after skull base tumor resection.s. Literatur In addition, Mokri reported on a patient with postcraniotomy CSF leak that paradoxically had postural headaches worse with lying down.s. Literatur In addition, tension pneumocephalus may concurrently develop with an active CSF leak through a “ball-valve” mechanism. The risk of tension pneumocephalus is higher when using a lumbar drain or continuous positive air pressure (CPAP) therapy for sleep apnea. Infection (wound or meningitis) is a serious but fortunately uncommon complication of VS surgery that may result in headache.s. Literatur ^,​ s. Literatur ^,​ s. Literatur Aseptic, or chemical meningitis, may develop in up to 5% of cases following cerebellopontine angle surgery and is thought to arise from the presence of residual postoperative inflammatory products, such as blood and bone dust, in the subarachnoid space. Headache from aseptic meningitis classically emerges while the patient is tapering off a perioperative steroid, and may be associated with pseudomeningocele, representing elevated intracranial pressures. In this setting, a lumbar puncture for CSF analysis, including culture, is often required to distinguish aseptic meningitis from bacterial meningitis.s. Literatur Hydrocephalus postoperatively may result in headache, visual changes, and reduced level of consciousness. The management of perioperative hydrocephalus is discussed further in Chapter 46.

Sinus thrombosis, sinus stenosis, or sacrifice of a dural sinus could result in holocephalic, severe pain.s. Literatur If persistent, venous hypertension could develop and result in focal neurologic deficits, vision loss, and/or seizures. Keiper and colleagues reported venous sinus thrombosis causing headache following both retrosigmoid and translabyrinthine craniotomy.s. Literatur Patients with venous sinus thrombosis developed postoperative symptoms consistent with intracranial hypertension including headache, vision changes, and papilledema. Imaging studies in these patients revealed occlusion of their dominant transverse and/or sigmoid sinus. Another study reported that postoperative transverse sinus thrombosis was more frequent following the translabyrinthine approach.s. Literatur In their study, all patients experience some degree of lateral sinus thrombosis following surgical resection of VSs, and it is unclear whether isolated sigmoid sinus thrombosis without concurrent transverse sinus occlusion contributes to clinically significant intracranial hypertension and postsurgical headache. The risk of dural sinus thrombosis is greatest when operating on the side with a dominant venous system, when the lateral sinus system is injured, or in patients with hypercoagulopathy. Suspected cases are optimally imaged using magnetic resonance imaging (MRI) with MR venography, or computed tomography (CT) with CT venography. Fortunately, the prevalence of clinically significant sinus thrombosis following VS surgery is very low. Chapter 45 discusses this topic further.

71.2.3 Clinical Phenotypes of Postoperative Headache in Patients with Vestibular Schwannoma

Approximately 30% of patients undergoing surgery for VS may have persistent pain lasting more than 3 to 6 months. There are several chronic headache categories that these patients may fall into. Schankin and colleagues assessed headaches in 95 patients undergoing VS surgery, all with a retrosigmoid approach.s. Literatur Thirty-two percent of those patients had a persistent headache with a severity of at least 6 out of 10 postoperatively for more than 6 months. When using the second edition of the International Classification of Headache Disorders (ICHD2), patient’s headache syndromes fell into five categories: tension type (46%), occipital nerve (16.6%), trigeminal neuropathy (16.6%), neuropathy of the intermedian nerve (10.0%), and cervicogenic headache (10.0%). This study assessed quality of headache type nearly 1 year after surgery. Some have suggested the quality of headache may change with time and therefore migrainous quality may be underrepresented.s. Literatur Other considerations for chronic postoperative headache causes include medication overuse headaches, migraine headaches,s. Literatur and temporomandibular joint dysfunction.s. Literatur Each of these headache types have unique locations, quality of pain, and precipitating factors. However, they can also be encompassed into the ICHD criteria of postcraniotomy headache. When serious causes have been ruled out, it is important to assess which category a patient’s headache syndrome might fit in so that treatment may be appropriately tailored (Fig. 71‑2 and Table 71‑2 ).

The following section reviews general considerations and approaches to headache management followed by a section on the evaluation and treatment of more specific, common phenotypes of chronic postoperative headache.

71.3.1 Preoperative Considerations

There are several preoperative considerations when counseling a patient on intervention for a VS. It is important to recognize that multiple studies have shown that a major risk factor for postoperative headache is the presence of preoperative headache.s. Literatur In this regard, it is useful to set expectations for the purpose of surgery so as to avoid unrealistic goals. In addition, one might consider determining if there is a primary headache disorder and consider preoperative proactive treatment. While no studies exist comparing the risk of postoperative headache with preemptive prophylactic treatment of the headache disorder prior to VS surgery, this could be considered. In addition, a history of anxiety and/or depression may increase the risk of postoperative headache. Identification and treatment of these comorbid conditions should be considered prior to surgery.

A careful consideration of treatment options should be discussed with the patient. For example, in a patient with severe headaches at baseline, can an approach other than retrosigmoid craniotomy be considered if surgery is pursued? Is the tumor amenable to observation, stereotactic radiosurgery, or another surgical approach?