Effect of Anatomical Sites On the Mechanical Properties of Spinal Dura Subjected to Biaxial Stretching

The spinal cord is encased by spinal meninges called the pia, arachnoid, and dura maters. Among these membranes, the dura mater is the thick and outermost layer and is the toughest and strongest. Thus, mechanical failure of the dura mater can lead to spontaneous cerebrospinal fluid leaks or hypovolemia, resulting in a complication or exacerbation of unfavorable symptoms involved in a mild traumatic brain injury. To develop protective equipment that can help prevent such injuries, accurate characterization of the spinal dura mater is required, especially regarding the mechanical properties at different anatomical sites. In this study, we used an equiload biaxial tensile tester to investigate the mechanical properties of porcine meningeal dura mater along the whole length of the spine. The resultant strain of the dorsal side was greater than that of the ventral side (P < 0.01), while the circumferential direction was significantly stiffer than the longitudinal direction (P < 0.01) at lower strains regardless of the spinal level. We also found that the material stiffness progressively increased from the cervical level to the thoracolumbar level at lower strains, which implies that the dura mater inherently possesses structurally preferred features or functions because the neck requires sufficient flexibility for daily activities. Further, Young's modulus was significantly less on the dorsal side than on the ventral side at higher strains (P < 0.05), suggesting that the dorsal side is readily elongated by spinal flexion even within the range of physiological motion.

Opiate Use After Endoscopic Endonasal Transsphenoidal Surgery

Background The literature on opiate use after endoscopic endonasal transsphenoidal surgery (EETS) is limited. Objective To determine the risk factors for higher opiate use following EETS and the quantity of opiates used after discharge. Methods A retrospective review of 144 patients undergoing EETS from July 2018 to July 2020 was conducted. Patient, tumor, and surgical factors were documented. Pain scores and medications used on postoperative days (POD) 0 and 1, and discharge prescriptions, were recorded. Opiate use was quantified using morphine milligram equivalents (MME) dose. Multiple linear regression determined risk factors independently associated with POD0 to 1 opiate use. Results On POD 0 to 1, mean pain score was 4.9/10 (standard deviation [SD] ± 2.0). Mean acetaminophen use was 3.4 tablets (SD ± 1.6; 650 mg per tablet). Mean opiate use was 35.6 MME (SD ± 36.3), equivalent to 4.7 tablets (SD ± 4.8) of oxycodone 5 mg. Multiple linear regression showed that current smokers required an additional 37.1 MME ( P = .011), and patients with grade 3 intraoperative cerebrospinal fluid leaks required an additional 36.7 MME ( P = .046) on POD0 to 1. On discharge, mean opiate prescription was 117.7 MME (SD ± 102.1), equivalent to 15.7 tablets (SD ± 13.6) of oxycodone 5 mg. Thirty-nine patients (27.1%) did not require prescriptions. Only 10 patients (6.9%) required opiate refill(s) within 30 days after surgery. Conclusion Patients undergoing EETS have higher opiate needs compared to those undergoing endoscopic sinus surgery, although the overall requirements are still considered low. Independent risk factors associated with higher opiate use in the immediate postoperative period included current smokers and grade 3 intraoperative cerebrospinal fluid leaks.

Expanded Transsphenoidal Trans-Lamina Terminalis Approach to Tumors Extending Into the Third Ventricle: Technique Notes and a Single Institute Experience

ObjectThe trans lamina terminalis approach (TLTA) has been described as a way to remove third ventricular tumors. The aim of this paper was to analyze the feasible outcomes of TLTA applied to tumors extending into the third ventricle in our institute.MethodsSuprasellar tumors (n = 149) were treated by the extended endonasal approach from September 2019 to December 2020 in Beijing Tiantan Hospital. Eleven of the tumors were treated by TLTA or TLTA via the trans-chiasm-pituitary corridor (TCPC). The surgical technique notes of TLTA were described and indications and outcomes of the approach were analyzed.ResultsThere were 11 patients enrolled in the study, six with papillary craniopharyngiomas, two with adamantinomatous craniopharyngiomas, one with a germinal cell tumor (GCT), one with cavernous malformation and one with chordoid glioma. Four of the patients received a radical resection by TLTA alone, while seven of them received TLTA via the TCPC. Gross total resection was achieved in eight patients (72.7%), and partial resection in three patients (27.3%). Visual function was improved in four of the 11 patients (36.4%), was unchanged in five patients (45.5%), and deteriorated in two patients (18.2%). New-onset hypopituitarism occurred in seven patients (63.3%) and new-onset diabetes insipidus occurred in two patients (18.2%). Electrocyte imbalance were observed in six patients (54.5%) at post-operative week 2. There were no surgery-related deaths or cerebrospinal fluid leaks. Postoperative intracranial infection was observed in one patient (9.1%), and during the follow-up period, tumor recurrence occurred in one patient (9.1%).ConclusionThe expanded TLTA provides a feasible suprachiasm corridor to remove tumors extending into the third ventricle, especially for craniopharyngiomas. Sound understanding of the major strengths and limitations of this approach, as well as strategies for complication avoidance, is necessary for its safe and effective application.

Endoscopic endonasal resection of sinonasal teratocarcinosarcoma with intracranial breakthrough: illustrative case

BACKGROUND Teratocarcinosarcoma traversing the anterior skull base is rarely reported in literature. The heterogenous and invasive features of the tumor pose challenges for surgical planning. With technological advancements, the endoscopic endonasal approach (EEA) has been emerging as a workhorse of anterior skull base lesions. To date, no case has been reported of EEA totally removing teratocarcinosarcomas with intracranial extensions. OBSERVATIONS The authors provided an illustrative case of a 50-year-old otherwise healthy man who presented with left-sided epistaxis for a year. Imaging studies revealed a 31 × 60-mm communicating lesion of the anterior skull base. Gross total resection via EEA was achieved, and multilayered skull base reconstruction was performed. LESSONS The endoscopic approach may be safe and effective for resection of extensive teratocarcinosarcoma of the anterior skull base. To minimize the risk of postoperative cerebrospinal fluid leaks, multilayered skull base reconstruction and placement of lumbar drainage are vitally important.