Splitting of the distal median nerve.

Variations of the nerves of the forearm can lead to unexpected clinical findings during physical examination. Additionally, surgery in this region might encounter and potentially damage the nerve in such patients. Here, we present a case of a high split of the median nerve and discuss the findings of the case as well as review salient reports in the literature. Knowledge of such a variation can be important in patient diagnosis and treatment.

The petrosal artery and its variations: a comprehensive review and anatomical study with application to skull base surgery and neurointerventional procedures.

BACKGROUND: The petrosal artery supplies several structures at the skull base and is often the focus of various neurointerventional procedures. Therefore, knowledge of its anatomy and variations is important to surgeons and interventionalists. MATERIALS AND METHODS: Twenty latex injected cadaveric heads (40 sides) underwent microsurgical dissection of the petrosal artery. Documentation of the course of the artery and its branches were made. Measurements of the petrosal artery's length and diameter were performed using microcallipers. RESULTS: A petrosal artery was identified on all sides. The mean length and diameter of the artery within the middle cranial fossa was 2.4 cm and 0.38 mm, respectively. Branches included the following: dural, ganglionic, V3 branches, branches extending through the foramen ovale, branches directly to the greater petrosal and lesser petrosal nerves, branches to the floor of the hiatus of the greater and lesser petrosal nerves, branch to the arcuate eminence, and superior tympanic artery. No statistically significant differences were noted between male and female specimens, but right-sided petrosal arteries were in general, larger in diameter than left sides. CONCLUSIONS: A thorough anatomical knowledge of the petrosal artery and to its relationship to the facial nerve and other neurovascular structures is necessary to facilitate effective endovascular treatment and to preclude facial nerve complications.

The first histological observation of a C1 posterior arch defect.

Deficiencies in the posterior arch of C1 have been well-studied with incidences ranging from 5.65% to 3% and five different classifications. Unfortunately, there is a paucity of information describing the detailed anatomy, muscle attachments, and histology of cases with a C1 posterior arch deficiency. We found a case of an isolated unilateral posterior arch defect in the 83-year-old male cadaver. Histology revealed that the posterior arch defect was filled with collagen fibres and fibrocartilaginous tissue without muscle or bony tissues. This is the first report detailing the histological findings of a posterior arch defect of C1.

Connection between V2 and V3 parts of the trigeminal nerve at the internal cranial base.

Anatomical variations can occasionally result in unexpected findings on physical examination. Here, we report two cases of seemingly unique connections between V2 and V3 parts of the trigeminal nerve. In these two cadaveric specimens, at the foramen ovale, small neural connections, confirmed with histology, were identified joining V2 to specifically, the motor root of V3. The findings of these two cadaveric specimens and the potential clinical ramifications are discussed.

Iliacus minor and psoas quartus muscles traversing the femoral nerve.

Anatomical variations of the nerves of the body can be relevant to surgical approaches anesthetic blockade, and other region procedures. Herein, we report a case of three muscle fascicles of the variant psoas quartus and iliacus minor muscles traversing the femoral nerve. Salient literature is reviewed regarding this phenomenon. Variations in the femoral nerve, such as illustrated in the current case, could also help explain hip and thigh pain, and failure of traditional anesthetic placement to block sensation from the femoral nerve completely. Given the procedural relevance of variations in the femoral nerve, further characterizations of nontraditional courses could help to avoid nerve injury during interventions.

"False" foramina and fissures of the skull: a narrative review with clinical implications.

"False" foramina and fissures of the skull are described as openings formed between the adjacent edges of two or more bones and not conduits directly through a single bone. Trauma and metabolic disorders appear to affect these foramina and fissures differently when compared to the "true" foramina and fissures. Therefore, the aim of this paper is to provide a narrative review of the current literature about "false" foramina and fissures of the skull and skull base with a focus on their clinical significance.

The posterior cranial fossa's dura mater innervation and its clinical implication in headache: a comprehensive review.

The pathophysiology of migraines and headaches has been a point of interest in research as they affect a large subset of the population, and the exact mechanism is still unclear. There is evidence implicating the dura mater and its innervation as contributing factors, especially at the posterior cranial fossa. Many modes of innervation have been identified, including the dorsal root ganglion, superior cervical ganglion, vagus nerve, trigeminal nerve, hypoglossal nerve, and glossopharyngeal nerve. While the exact method of innervation is still under investigation, there is strong evidence suggesting that different types of headaches (migraine vs. occipital vs. cervicogenic) are due to specific nerves and inflammatory mediators that contribute to the dura mater in some way. By understanding how these innervation patterns manifest clinically, the course of treatment can be tailored based on the physiological aetiology. Here, we present a comprehensive literature review of the current research regarding the innervation of the dura mater of the posterior cranial fossa and its clinical implications.

A previously unreported variant of the auriculotemporal nerve.

Venous fenestrations are rare and when present often are not pierced by regional nerves. Herein, we report an unusual case of a fenestrated superficial temporal vein (STV). Anterior to the external ear, where the STV and superficial temporal artery normally travel with the auriculotemporal nerve (ATN), the nerve was found to pierce the STV. The fenestration within the STV was approximately 0.35mm in diameter, and there was no sign of compression of the ATN as it traversed this vessel. Following the site of penetration of the STV by the ATN, the nerve had a normal course into the skin and surrounding fascia. To our knowledge, this is the first report of a fenestrated STV being pierced by the ATN. Such an anatomical variation might be considered by clinicians who treat patients with pathology of this region.

Simultaneous duplication of the tendon of plantaris with multiple tendinous connections into the crural fascia.

The plantaris muscle (PM) typically begins with a short, fusiform muscle belly and continues as a slim tendon traversing distally between the gastrocnemius and soleus to attach into the calcaneus directly or Achilles tendon. Conventionally, it has been of most interest as a donor for surgeons plantaris tendon (PT) grafting and recent studies have implicated the PT in the development of Achilles tendinopathy. During routine cadaveric dissection, one such anatomical variation was identified in a cadaver with two distal tendons of the PM and also multiple tendon connections into the crural fascia. While similar variants have been reported before in isolation, to our knowledge, this has been rarely reported illustrating the coexistence of a duplicated PT with simultaneous fascial connections into the crural fascia. The clinical implications of such a finding are discussed.

Postfixed lumbosacral plexus with split L5 ventral ramus and furcal nerve arising from L5.

Variations of the peripheral nerve plexuses are important to those clinicians who diagnose and treat patients with pathology of their parts. During routine dissection, a postfixed lumbosacral plexus with a furcal nerve arising from L5, not L4, was discovered. In addition, the case was found to have a split L5 ventral ramus. Such a variation might become clinically significant during clinical presentations of radiculopathy. With a better understanding of the fucal nerve variation presented here, along with previously documented variations, the diagnostic and treatment procedures for atypical radiculopathy can be refined, reducing the rates of nerve injury and failed back surgery.

Chiari I malformation with craniosynostosis and persistent falcine sinus draining into the straight sinus.

Owing to the interconnected nature of the brain, anatomical variations in one area often coincide with, or are caused by, abnormalities in another. During dissection of a specimen with both Chiari I malformation and craniosynostosis, a persistent falcine sinus was observed to drain into the straight sinus. Such a variant should be noted by physicians as it could alter treatment plans and require more detailed imaging procedures prior to surgical correction. Herein, we report the case and discuss the possible embryological origins and clinical significance of the variant.

Rare variation of the furcal nerve.

Variations in the course of the lumbar plexus and lumbosacral trunk have been explored with respect to variant nerve roots being indicated in atypical sciatic pain. Typically, the furcal nerve emerges from the L4 nerve root, with a single contribution. However, we report a case where the furcal nerve was found to arise not only from the L4 nerve but also from the obturator nerve. This anatomical variation is explored in terms of its clinical significance and implications in lumbar and sacral plexus associated procedures.

What is the suboccipital nerve? Tracking this confusing historical nomenclature.

Since its initial description in the 2nd century, the suboccipital nerve has maintained a number of varying terminologies. Many of these terms were created in the 18th and 19th centuries to describe the first set of cervical spinal nerves that exited the spinal cord between the cranium and the atlas. Though the many terminologies have been reduced to mainly the suboccipital nerve, there are still two prevalent definitions used for this nerve. Herein, we discuss the history of the first spinal nerve and its branches with special attention to varying terminologies over time. Recent literature has described the suboccipital nerve as the entire nerve or as simply the dorsal ramus of the C1 spinal nerve. This interchangeability may lead to confusion about the specific part of the nerve being discussed. Following a review of the literature, we recommend the term C1 spinal nerve be applied to the entire nerve, whereas, suboccipital nerve be reserved solely for the posterior branch of the C1 spinal nerve.

Previously undescribed variant muscle connecting longissimus and semispinalis capitis muscles.

Thelongissimus capitis and the semispinalis capitis both function to bilaterally extend and unilaterally rotate the head. Typically, these muscles are distinct with origins and insertions at independent locations along the vertebral column. During a routine cadaveric dissection, an unusual muscle strip was identified between the longissimus capitis andsemispinalis capitismuscles on the left, posterior neck. This anatomical variation may have developed due to an incomplete or abnormal columnar segregation during gestation. The presence of this muscle strip contributes to previous case reports that have identified abnormal musculature between and along the longissimus and semispinalis muscles. Awareness of this muscular variant should be kept in mind by clinicians and surgeons who treat/operate this area of the body.

Coiling of large and giant aneurysms: complications and long-term results of 334 cases.

BACKGROUND AND PURPOSE: Large and giant intracranial aneurysms are increasingly treated with endovascular techniques. The goal of this study was to retrospectively analyze the complications and long-term results of coiling in large and giant aneurysms (≥ 10 mm) and identify predictors of outcome. MATERIALS AND METHODS: A total of 334 large or giant aneurysms (≥ 10 mm) were coiled in our institution between 2004 and 2011. Medical charts and imaging studies were reviewed to determine baseline characteristics, procedural complications, and clinical/angiographic outcomes. Aneurysm size was 15 mm on average. Two hundred twenty-five aneurysms were treated with conventional coiling; 88, with stent-assisted coiling; 14, with parent vessel occlusion; and 7, with balloon-assisted coiling. RESULTS: Complications occurred in 10.5% of patients, with 1 death (0.3%). Aneurysm location and ruptured aneurysms predicted complications. Angiographic follow-up was available for 84% of patients at 25.4 months on average. Recanalization and retreatment rates were 39% and 33%, respectively. Larger aneurysm size, increasing follow-up time, conventional coiling, and aneurysm location predicted both recurrence and retreatment. The annual rebleeding rate was 1.9%. Larger aneurysm size, increasing follow-up time, and aneurysm location predicted new or recurrent hemorrhage. Favorable outcomes occurred in 92% of patients. Larger aneurysm size, poor Hunt and Hess grades, and new or recurrent hemorrhage predicted poor outcome. CONCLUSIONS: Coiling of large and giant aneurysms has a reasonable safety profile with good clinical outcomes, but aneurysm reopening remains very common. Stent-assisted coiling has lower recurrence, retreatment, and new or recurrent hemorrhage rates with no additional morbidity compared with conventional coiling. Aneurysm size was a major determinant of recanalization, retreatment, new or recurrent hemorrhage, and poor outcome.

Stent-assisted coiling versus balloon remodeling of wide-neck aneurysms: comparison of angiographic outcomes.

BACKGROUND AND PURPOSE: Stent-assisted coiling and balloon-assisted coiling are 2 well-established techniques for treatment of wide-neck intracranial aneurysms. A direct comparative analysis of angiographic outcomes with the 2 techniques has not been available. We compare the angiographic outcomes of wide-neck aneurysms treated with stent-assisted coiling versus balloon-assisted coiling. MATERIALS AND METHODS: A retrospective review was conducted on 101 consecutive patients treated at our institution, 69 with stent-assisted coiling and 32 with balloon-assisted coiling. Two multivariate logistic regression analyses were performed to determine predictors of aneurysm obliteration and predictors of progressive aneurysm thrombosis at follow-up. RESULTS: The 2 groups were comparable with respect to all baseline characteristics with the exception of a higher proportion of ruptured aneurysms in the balloon-assisted coiling group (65.6%) than in the stent-assisted coiling group (11.5%, P < .001). Procedural complications did not differ between the stent-assisted coiling group (6%) and the balloon-assisted coiling group (9%, P = .5). The rates of complete aneurysm occlusion (Raymond score 1) at the most recent follow-up were significantly higher for the stent-assisted coiling group (75.4%) compared with the balloon-assisted coiling group (50%, P = .01). Progressive occlusion of incompletely coiled aneurysms was noted in 76.6% of aneurysms in the stent-assisted coiling group versus 42.8% in the balloon-assisted coiling group (P = .02). Retreatment rates were significantly lower with stent-assisted coiling (4.3%) versus balloon-assisted coiling (15.6%, P = .05). In multivariate analysis, stented aneurysms independently predicted both complete aneurysm obliteration and progression of occlusion. CONCLUSIONS: Stent-assisted coiling may yield lower rates of retreatment and higher rates of aneurysm obliteration and progression of occlusion at follow-up than balloon-assisted coiling with a similar morbidity rate.

Endovascular treatment of posterior communicating artery aneurysms with oculomotor nerve palsy: clinical outcomes and predictors of nerve recovery.

BACKGROUND AND PURPOSE: ONP is a well-known presentation of PcomA aneurysms. Reports on recovery of ONP with endovascular coiling have been limited to small case series. We assessed the safety and efficacy of endovascular therapy in a series of PcomA aneurysms with ONP. MATERIALS AND METHODS: We reviewed 37 patients with ONP who underwent endovascular treatment in our institution between 2005 and 2011. Published studies were also reviewed to determine the overall rate of ONP recovery with endovascular therapy. RESULTS: Nineteen patients (51.4%) presented with complete ONP, and 18 (48.6%), with partial ONP. Conventional coiling was performed in 31 (83.8%) patients; stent-assisted coiling, in 4 (10.8%); and balloon remodeling, in 2 (5.4%). There was 1 (2.7%) procedural complication (a transient thromboembolic event). Twenty-seven (73%) patients were treated within 3 days from symptom onset. At the last available clinical follow-up, ONP resolution was complete in 14 (37.8%) patients and partial in 19 (51.4%). Only 4 (10.8%) patients showed no signs of nerve recovery. In multivariate analysis, partial ONP and longer follow-up durations were predictors of complete nerve recovery. Treatment timing, type of endovascular embolization, subarachnoid hemorrhage, and initial degree of aneurysm occlusion were not predictors of nerve recovery. Of 169 patients reported in the literature (including ours), ONP resolved completely in 73 (43.2%) patients and partially in 73 (43.2%). CONCLUSIONS: Endovascular therapy is a safe and highly efficient alternative to surgical clipping for PcomA aneurysms with ONP.

Intracranial vertebral artery dissections: evolving perspectives.

Intracranial vertebral artery dissection (VAD) represents the underlying etiology in a significant percentage of posterior circulation ischemic strokes and subarachnoid hemorrhages. These lesions are particularly challenging in their diagnosis, management, and in the prediction of long-term outcome. Advances in the understanding of underlying processes leading to dissection, as well as the evolution of modern imaging techniques are discussed. The data pertaining to medical management of intracranial VADs, with emphasis on anticoagulants and antiplatelet agents, is reviewed. Surgical intervention is discussed, including, the selection of operative candidates, open and endovascular procedures, and potential complications. The evolution of endovascular technology and techniques is highlighted.

Superior hypophyseal artery aneurysms have the lowest recurrence rate with endovascular therapy.

BACKGROUND AND PURPOSE: Given the challenges posed by surgical clipping, endovascular techniques have been increasingly used to treat SHA aneurysms. The purpose of this study was to assess the safety and efficacy of endovascular techniques in the treatment of SHA aneurysms. MATERIALS AND METHODS: Medical charts and initial and follow-up angiograms were reviewed retrospectively for all patients treated with endovascular procedures at our institution between January 2006 and February 2011. RESULTS: We identified 87 patients with SHA aneurysms who were treated with endovascular techniques. Of these patients, 79 were women and only 8 were men (90.8% female predominance). Thirty-five patients were treated with coil embolization; 45, with stent-assisted coiling; 4, with balloon-assisted coil embolization; and 3, with a flow-diversion technique. Minor complications occurred in 2 patients (2.2%). None of the patients had a major complication. The mortality and permanent morbidity rates related to the procedure were 0%. Imaging follow-up was available for 89.4% of patients (DSA in 65, MRA in 11 patients) at a mean time point of 10.4 months (range, 6-60 months). Of the 76 patients with available follow-up, 3 patients had a recurrence (3.9%) and only 1 required further intervention (1.3%). Stent-assisted coiling was associated with lower recurrence rates than simple coil embolization. CONCLUSIONS: SHA aneurysms have the lowest recurrence rate with endovascular treatment compared with aneurysms in other locations by using historical data. Because of its safety and efficacy, endovascular therapy should be considered the procedure of choice for the treatment of SHA aneurysms.

The efficacy of endovascular stenting in the treatment of supraclinoid internal carotid artery blister aneurysms using a stent-in-stent technique.

BACKGROUND AND PURPOSE: Blister aneurysms of the supraclinoid ICA represent a rare but well-documented cause of subarachnoid hemorrhage. These aneurysms are difficult to detect, and their surgical treatment is challenging, with high morbidity and mortality rates. The reports currently in the literature that describe the surgical and endovascular treatment of these aneurysms offer no clear consensus on the optimal treatment. We describe a staged endovascular treatment entailing stenting using a stent-in-stent technique, as well as planned but delayed embolization as the aneurysm increases in size to allow the introduction of coils. MATERIALS AND METHODS: We performed a retrospective review of all cerebral angiograms performed at our institution over an 8-month period for evaluation of subarachnoid hemorrhage, identifying 6 ICA blister aneurysms. RESULTS: All 6 blister aneurysms were located in the supraclinoid ICA. The stent-in-stent technique was used for the initial treatment of all patients. Three patients had no residual or recurrent aneurysm following initial treatment. Three patients required retreatment with coils after continued growth of the aneurysm, identified on follow-up angiography. Five patients had good recovery (average mRS score of 1), and 1 patient had poor neurologic recovery (mRS score of 3) due to a large hemorrhagic infarction. CONCLUSIONS: Our case series suggests that staged endovascular treatment entailing the use of a stent-in-stent technique, augmented with subsequent coil embolization as necessary for progressive disease, is a viable endovascular option for treating ruptured supraclinoid blister aneurysms, allowing for parent artery preservation.