Case Report: Acute common peroneal nerve injury after posterior lumbar decompression surgery.

Spine surgery is a prevalently performed procedure. Some authors have proposed an age-related surge in surgical and general complications. During spine surgery, patients are placed in positions that are not physiologic, would not be tolerated for prolonged periods by the patient in the awake state, and may lead to complications. Understanding these uncommon complications and their etiology is pivotal to prevention and necessary. The patient is a 76-year-old woman referred to the outpatient department of neurosurgery in February 2022 by her physiatrist with a chief complaint of chronic low back pain and numbness over the left leg. Lumbar spine magnetic resonance imaging revealed degenerative disc disease and posterior disc bulging at the levels of L2/3∼L5/S1 with compression of the thecal sac. After receiving anti-inflammatory medication, nerve block and caudal block, her symptoms persisted. She was referred to a neurosurgeon for surgical intervention. We diagnosed spinal stenosis with left L3 and L4 radiculopathy, and elective decompression surgery was scheduled a few days later. We performed discectomies at L2/3 and L3/4 and left unilateral laminectomy at L2 and L3 for bilateral decompression. Following an uneventful surgery, the patient was extubated, and her left leg pain improved, but pain over the right outer calf with drop foot developed. A second lumbar MRI the next day revealed no evidence of recurrent disc herniation or epidural hematoma. Then, she received nerve conduction velocity and needle electromyogram on postoperative day 2, and the studies indicated right common peroneal nerve entrapment neuropathy. After medication with steroids and foot splint use, right leg pain improved. However, weak dorsiflexion of the right ankle persisted. We referred this patient to a physiatrist and OPD for follow-up after discharge. Perioperative peripheral nerve injury (PPNI) is most commonly caused by peripheral nerve ischemia due to abnormal nerve lengthening or pressure and can be exacerbated by systemic hypotension. Any diseases affecting microvasculature and anatomical differences may contribute to nerve injury or render patients more susceptible to nerve injury. Prevention, early detection and intervention are paramount to reducing PPNI and associated adverse outcomes. The use of intraoperative neuromonitoring theoretically allows the surgical team to detect and intervene in impending PPNI during surgery.

Endoscopically assisted presigmoid retrolabyrinthine approach to the lateral mesencephalic sulcus: a cadaveric study with comparison to the variant supracerebellar infratentorial approaches.

The supracerebellar infratentorial (SCIT) approach is commonly used to gain access to the lateral mesencephalic sulcus (LMS), which has been established as a safe entry point into the posterolateral midbrain. This study describes a lateral variant of the SCIT approach, the supreme-lateral SCIT approach, for accessing the LMS through the presigmoid retrolabyrinthine craniectomy and quantitatively compares this approach with the paramedian and extreme-lateral SCIT approaches. Anatomical dissections were performed in four cadaveric heads. In each head, the supreme-lateral SCIT approach was established on one side, following a detailed description of each step, whereas the paramedian and supreme-lateral SCIT approaches were established on the other side. Quantitative measurements of the exposed posterolateral midbrain, the angles of LMS entry, and the depth of surgical corridors were recorded and compared between the three SCIT approach variants. The supreme-lateral (67.70 ± 23.14 mm2) and extreme-lateral (70.83 ± 24.99 mm2) SCIT approaches resulted in larger areas of exposure anterior to the LMS than the paramedian SCIT approach (38.61 ± 9.84 mm2); the supreme-lateral SCIT approach resulted in a significantly smaller area of exposure posterior to the LMS (65.24 ± 6.81 mm2) than the other two variants (paramedian = 162.75 ± 31.98 mm2; extreme-lateral = 143.10 ± 23.26 mm2; both P < .001). Moreover, the supreme-lateral SCIT approach resulted in a surgical corridor with a shallower depth and a smaller angle relative to the horizontal plane than the other two variants. The supreme-lateral SCIT approach is a more lateral approach than the extreme-lateral SCIT approach, providing a subtemporal approach with direct LMS visualization. The supreme-lateral SCIT offers the benefits of both subtemporal and SCIT approaches and represents a suitable option for the management of selected midbrain pathologies.

Quantitative comparison of endoscopically assisted endonasal, sublabial and transorbital transmaxillary approaches to the anterolateral skull base.

OBJECTIVES: The aim of this anatomical study is to make quantitative comparison among three endoscopic approaches, encompassing contralateral endonasal transseptal transmaxillary transpterygoid approach (contralateral EEA), endoscopic sublabial transmaxillary transalisphenoid (Caldwell-Luc) approach and endoscopic transorbital transmaxillary approach through inferior orbital fissure (ETOA), to the anterolateral skull base for assisting preoperative planning. DESIGN & PARTICIPANTS: Anatomical dissections were performed in four adult cadaveric heads bilaterally using three endoscopic transmaxillary approaches described above. SETTING: Skull Base Laboratory at the National Defense Medical Center. MAIN OUTCOME MEASURES: The area of exposure, angles of attack and depth of surgical corridor of each approach were measured and obtained for statistical comparison. RESULTS: The ETOA had significantly larger exposure over middle cranial fossa (731.40 ± 80.08 mm2 ) than contralateral EEA (266.60 ± 46.74 mm2 ) and Caldwell-Luc approach (468.40 ± 59.67 mm2 ). In comparison with contralateral EEA and Caldwell-Luc approach, the ETOA offered significantly greater angles of attack and shorter depth of surgical corridor (P < .05 for all comparisons). CONCLUSIONS: The ETOA is the superior choice for target lesion occupying multiple compartments with its epicentre located in the middle cranial fossa or superior portion of infratemporal fossa.

Endoscopic transcanal transpetrosal approach to the petroclival region: a cadaveric study with comparison to the Kawase approach.

This study introduces expanded application of the endoscopic transcanal approach with anterior petrosectomy (ETAP) in reaching the petroclival region, which was compared through a quantitative analysis to the middle fossa transpetrosal-transtentorial approach (Kawase approach). Anatomical dissections were performed in five cadaveric heads. For each head, the ETAP was performed on one side with a detailed description of each step, while the Kawase approach was performed on the contralateral side. Quantitative measurements of the exposed area over the ventrolateral surface of the brainstem, and of the angles of attack to the posterior margin of the trigeminal nerve root entry zone (CN V-REZ) and porus acusticus internus (PAI) were obtained for statistical comparison. The ETAP provided significantly larger exposure over the ventrolateral surface of the pons (93.03 ± 21.87 mm2) than did the Kawase approach (34.57 ± 11.78 mm2). In contrast to the ETAP, the Kawase approach afforded greater angles of attack to the CN V-REZ and PAI in the vertical and horizontal planes. The ETAP is a feasible and minimally invasive procedure for accessing the petroclival region. In comparison to the Kawase approach, the ETAP allows for fully anterior petrosectomy and larger exposure over the ventrolateral surface of the brainstem without passing through the cranial nerves or requiring traction of the temporal lobe.

Endoscopic transorbital approach to anterolateral skull base through inferior orbital fissure: a cadaveric study.

BACKGROUND: Endoscopic transorbital approach (eTOA) has been announced as an alternative minimally invasive surgery to skull base. Owing to the inferior orbital fissure (IOF) connecting the orbit with surrounding pterygopalatine fossa (PPF), infratemporal fossa (ITF), and temporal fossa, the idea of eTOA to anterolateral skull base through IOF is postulated. The aim of this study is to access its practical feasibility. METHODS: Anatomical dissections were performed in five human cadaveric heads (10 sides) using 0-degree and 30-degree endoscopes. A stepwise description of eTOA to anterolateral skull base through IOF was documented. The anterosuperior corner of the maxillary sinus in the horizontal plane of the upper edge of zygomatic arch was defined as reference point (RP). The distances between the RP to the foramen rotundum (FR), foramen ovale (FO), and Gasserian ganglion (GG) were measured. The exposed area of anterolateral skull base in the coronal plane of the posterior wall of the maxillary sinus was quantified. RESULTS: The surgical procedure consisted of six steps: (1) lateral canthotomy with cantholysis and preseptal lower eyelid approach with periorbita dissection; (2) drilling of the ocular surface of greater sphenoid wing and lateral orbital rim osteotomy; (3) entry into the maxillary sinus and exposure of PPF and ITF; (4) mobilization of infraorbital nerve with drilling of the infratemporal surface of the greater sphenoid wing and pterygoid process; (5) exposure of middle cranial fossa, Meckel's cave, and lateral wall of cavernous sinus; and (6) reconstruction of orbital floor and lateral orbital rim. The distances measured were as follows: RP-FR = 45.0 ± 1.9 mm, RP-FO = 55.7 ± 0.5 mm, and RP-GG = 61.0 ± 1.6 mm. In comparison with the horizontal portion of greater sphenoid wing, the superior and inferior axes of the exposed area were 22.3 ± 2.1 mm and 20.5 ± 1.8 mm, respectively. With reference to the FR, the medial and lateral axes of the exposed area were 11.6 ± 1.1 mm and 15.8 ± 1.6 mm, respectively. CONCLUSIONS: The eTOA through IOF can be used as a minimally invasive surgery to access whole anterolateral skull base. It provides a possible resolution to target lesion involving multiple compartments of anterolateral skull base.

Impact of global spine balance and cervical regional alignment on determination of postoperative cervical alignment after laminoplasty.

The aim of this study is to analyze the combined impact of preoperative T1 slope (T1S) and C2-C7 sagittal vertical axis (C2-C7 SVA) on determination of cervical alignment after laminoplasty.Forty patients undergoing laminoplasty for cervical spondylotic myelopathy (CSM) with more than 2 years follow-up were enrolled. Three parameters, including cervical lordosis, T1S, and C2-C7 SVA, were measured by preoperative and postoperative radiographs. Receiver operating characteristics (ROC) curve analysis was used to determine the optimal cut-off values of preoperative T1S and C2-C7 SVA for predicting postoperative loss of cervical lordosis. Patients were classified into 4 categories based on cut-off values of preoperative T1S and C2-C7 SVA. The primary outcome was postoperative C2-C7 SVA. Change in radiographic parameters between 4 groups were compared and analyzed.Optimal cut-off values for predicting loss of cervical lordosis were T1S of 20 degrees and C2-C7 SVA of 22 mm. Patients with small C2-C7 SVA, no matter what the value of T1S, got slight loss of cervical lordosis and increase in C2-C7 SVA. Patients with low T1S and large SVA (T1 ≤20° and SVA >22 mm) got postoperative correction of kyphosis and decrease of C2-C7 SVA. However, patients with high T1S and large SVA (T1 >20° and SVA >22 mm) got mean postoperative C2-C7 SVA value of 37.06 mm, close to the threshold value of 40 mm.Determination of cervical alignment after laminoplasty relies on the equilibrium between destruction of cervical structure, kyphotic force, and adaptive compensation of whole spine, lordotic force. Lower T1S means bigger compensatory ability to adjust different severity of cervical sagittal malalignment, and vice versa.

Quantitative analysis of anatomical relationship between cavernous segment internal carotid artery and pituitary macroadenoma.

Cavernous segment internal carotid artery (CSICA) injury during endoscopic transsphenoidal surgery for pituitary tumor is rare but fatal. The aim of this study is to investigate anatomical relationship between pituitary macroadenoma and corresponding CSICA using quantitative means with a sense to improve safety of surgery.In this retrospective study, a total of 98 patients with nonfunctioning pituitary macroadenomas undergoing endoscopic transsphenoidal surgeries were enrolled from 2005 to 2014. Intercarotid distances between bilateral CSICAs were measured in the 4 coronal levels, namely optic strut, convexity of carotid prominence, median sella turcica, and dorsum sellae. Parasellar extension was graded and recorded by Knosp-Steiner classification.Our findings indicated a linear relationship between size of pituitary macroadenoma and intercarotid distance over CSICA. The correlation was absent in pituitary macroadenoma with Knosp-Steiner grade 4 parasellar extension.Bigger pituitary macroadenoma makes more lateral deviation of CSICA. While facing larger tumor, sufficient bony graft is indicated for increasing surgical field, working area and operative safety.

Uremic tumoral calcinosis causing atlantoaxial subluxation and spinal cord compression in a patient on continuous ambulatory peritoneal dialysis.

Uremic tumoral calcinosis (UTC) is a form of metastatic tissue calcification unique to dialysis patients, manifesting with amorphous and cystic masses containing calcium phosphate deposits in periarticular soft tissue. An involvement of the cervical spine with bone destruction is extremely rare in UTC. We describe a 44-year-old uremic female on long-term continuous ambulatory peritoneal dialysis who developed UTC in the peri-odontoid region with consequent atlantoaxial subluxation and spinal cord compression, featuring severe neck soreness, headache, and hypertension. Surgical removal of the destructive cervical spine lesion, showing typical tumoral calcinosis on histology, completely resolved the clinical symptoms. To date, the patient maintains uneventful postoperative course with tight control of serum phosphorus, calcium, and secondary hyperparathyroidism by medical treatment. We also review other reported unusual cases of UTC involving the cervical spine and discuss the differential diagnosis of destructive spinal lesions in uremic patients, such as UTC, dialysis-related amyloidosis, and brown tumors.

Use of spinous processes to determine the laterally angulated trajectory for placement of lateral mass screws: an image analysis.

BACKGROUND: Lateral mass screw placement techniques have been broadly described in the literature. Differences in these techniques are related to entry points, lateral angulations and the cephalocaudal axis. AIM: We evaluated 20 patients who underwent lateral mass screw placement between 2007 and 2009. Computed tomography (CT) scans of the cervical vertebrae were analyzed for each patient. MATERIAL AND METHODS: We measured the maximal transition from the midpoint of the lateral mass to a proposed intersection point by a line connecting the corresponding spinous process and outermost rim of the transverse foramen at each level. This determined an optimal entry point during the tip of screw tilted on the same level of spinous process. RESULTS: The results revealed that a screw entry point less than 3 mm medial to the midpoint of the lateral mass could safely avoid violation of the vertebral artery. CONCLUSIONS: The current study uses imaging analysis to demonstrate that spinous processes are an intraoperative landmark to aid surgeons in determining safe lateral mass screw trajectories. The limited-scale case results support our prediction from the image analysis. Depending on intraoperative landmarks, lateral mass screws could be safely and comfortably placed with good clinical outcomes.

The misplacement of external ventricular drain by freehand method in emergent neurosurgery.

External ventricular drain (EVD) placement is one of the most basic and common neurosurgical procedure which most was performed by young neurosurgical trainees. This study is conducted to determinate the safe and accuracy of EVD placement by freehand method. About 129 EVD placements were evaluated in this study. Eighty-three catheters (64.3%) were located in the ipsilateral frontal horn or third ventricle. The functional accuracy was 86%. Of eighteen misplaced catheters, only 4 (3.1%) catheters were nonfunctional, requiring a replacement or reposition. The higher misplaced rate was significantly observed in patients whose head CT scans revealed the lower hydrocephalus ratio (28.85%) and the smaller ventricular size (5.6 mm). Twenty-one (16.2%) new hemorrhages associated with EVD placements were observed. Using the freehand method, EVD placement is a safe and effective procedure in management of these emergent neurosurgical diseases.

Transorbital penetrating brain injury by branchlet: a rare case.

Penetrating injury of the brain and skull is uncommon, representing about 0.4% of head injuries. With advances in radiological techniques such as high-resolution and reconstruction computed tomography (CT), assessment of injuries is more accurate and easier. In this article, we report the case of a 46-year-old man presenting with head injury after a branchlet had penetrated through the right orbit into the brain. CT scan of the brain revealed diffuse subarachnoid hemorrhage, intraventricular hemorrhage, and mild obstructive hydrocephalus. CT scan of the brain with reconstruction revealed that the branchlet tip penetrated through the medial aspect of the right orbit to the parasellar region. CT scan of the brain with contrast showed gradual tapering of the right proximal internal carotid artery with total occlusion after the carotid bulb. Advance radiological examinations, such as three-dimensional CT, are required to obtain the correct emergent diagnosis and treatment of such injuries.

Problem of dural tail sign in glioblastoma multiforme?

A dural tail, which is a linear enhancement along the dura mater on contrast T1-weighted resonance images, is considered as a common and useful sign for distinguishing meningioma from other intracranial lesions. However, the specific nature of dura tail signs is still controversial. To the best of our knowledge, only seven cases of glioblastoma multiforme have been described with dural tail signs. Here, we report a case of glioblastoma multiforme with a dural tail sign and cerebrospinal fluid cleft sign and review the relevant literature.