Minimally Invasive Far Lateral Lumbar Discectomy With Modified Technique: Symptomatic Relief and Intersegmental Stability Study.

OBJECTIVE: To evaluate the use of a modified minimally invasive surgery (MIS) technique for far lateral lumbar discectomy (FLDH) that minimizes the degree of bony drilling required for nerve root decompression, increasing postoperative pain reduction rate with reduced risk of iatrogenic spinal instability. SUMMARY OF BACKGROUND DATA: FLDH accounts for approximately 10% of all lumbar disc herniations and is increasingly recognized in the era of advanced imaging techniques. These disc herniations typically result in extra-foraminal nerve root compression. Minimally invasive spine techniques are increasingly performed with various degrees of foraminal and facet removal to decompress the affected nerve root. METHODS: The study design involves a single institutional, retrospective cohort technical review. The review was completed of all patients undergoing MIS far lateral lumbar discectomy between 2010 and 2020. Cross-sectional, summary statistics were calculated for all variables. Counts and percentages were recorded for categorical variables and mean and standard deviations were calculated for continuous variables. RESULTS: A total of 48 patients underwent MIS far lateral lumbar discectomies (FLLD) from 2010 to 2020. The mean age was 63 ± 11.5 years (60.4% males), the mean BMI was 28.5 ± 5.5, and 20.8% smokers. The most common presenting complaint was both low back and radicular pain (79.2%) with 8.3% of patients suffering from motor weakness preoperatively. The mean follow-up time was 4.3 ± 2.7. The mean length of stay was 1.3 ± 1.4 days with 77.1% of patients discharged postoperative day one. Forty-three patients (93.5%) had improvement in their symptoms. Twenty-seven (58.7%) had complete resolution in 2.6 months on average. Six patients (13%) had immediate symptom resolution postoperatively. CONCLUSIONS: Our modified technique for FLLD allows MIS access to the extra-foraminal site of nerve root compression without the need for bony drilling. This minimizes postoperative pain and reduces the risk of iatrogenic spinal instability without sacrificing symptom resolution.

The Validity of the Koos Classification System With Respect to Facial Nerve Function.

BACKGROUND: The Koos classification of vestibular schwannomas is designed to stratify tumors based on extrameatal extension and compression of the brainstem. Our prior study demonstrated excellent reliability. No study has yet assessed its validity. OBJECTIVE: To present a retrospective study designed to assess the validity of the Koos grading system with respect to facial nerve function following treatment of 81 acoustic schwannomas. METHODS: We collected data retrospectively from 81 patients with acoustic schwannomas of various Koos grades who were treated with microsurgical resection or stereotactic radiosurgery. House-Brackmann (HB) scores were used to assess facial nerve function and obtained at various time points following treatment. We generated Spearman's rho and Kendall's tau correlation coefficients along with a logistic regression curve. RESULTS: We found no significant difference in the presence or absence of facial dysfunction by Koos classification when looking at all patients. There was a positive but fairly weak correlation between HB score and Koos classification, which was only significant at the first postoperative clinic appointment. There was a statistically significant difference in the presence or absence of facial dysfunction between patients treated with surgery vs radiation, which we expected. We found no statistically significant difference when comparing surgical approaches. Logistic regression modeling demonstrated a poor ability of the Koos grading system to predict facial nerve dysfunction following treatment. CONCLUSION: The Koos grading system did not predict the presence of absence of facial nerve dysfunction in our study population. There were trends within subgroups that require further exploration.

Reserved Bed Program Reduces Neurosciences Intensive Care Unit Capacity Strain: An Implementation Study.

BACKGROUND: Neurosciences intensive care units (NICUs) provide institutional centers for specialized care. Despite a demonstrable reduction in morbidity and mortality, NICUs may experience significant capacity strain with resulting supraoptimal utilization and diseconomies of scale. We present an implementation study in the recognition and management of capacity strain within a large NICU in the United States. Excessive resource demand in an NICU creates significant operational issues. OBJECTIVE: To evaluate the efficacy of a Reserved Bed Pilot Program (RBPP), implemented to maximize economies of scale, to reduce transfer declines due to lack of capacity, and to increase transfer volume for the neurosciences service-line. METHODS: Key performance indicators (KPIs) were created to evaluate RBPP efficacy with respect to primary (strategic) objectives. Operational KPIs were established to evaluate changes in operational throughput for the neurosciences and other service-lines. For each KPI, pilot-period data were compared to the previous fiscal year. RESULTS: RBPP implementation resulted in a significant increase in accepted transfer volume to the neurosciences service-line (P = .02). Transfer declines due to capacity decreased significantly (P = .01). Unit utilization significantly improved across service-line units relative to theoretical optima (P < .03). Care regionalization was achieved through a significant reduction in "off-service" patient placement (P = .01). Negative externalities were minimized, with no significant negative impact in the operational KPIs of other evaluated service-lines (P = .11). CONCLUSION: Capacity strain is a significant issue for hospital units. Reducing capacity strain can increase unit efficiency, improve resource utilization, and augment service-line throughput. RBPP implementation resulted in a significant improvement in service-line operations, regional access to care, and resource efficiency, with minimal externalities at the institutional level.

Koos Classification of Vestibular Schwannomas: A Reliability Study.

BACKGROUND: The Koos classification of vestibular schwannomas is designed to stratify tumors based on extrameatal extension and compression of the brainstem. While this classification system is widely reported in the literature, to date no study has assessed its reliability. OBJECTIVE: To assess the intra- and inter-rater reliability of the Koos classification system. METHODS: After institutional review board approval was obtained, a cross-sectional group of the Magnetic Resonance imagings of 40 patients with vestibular schwannomas varying in size comprised the study sample. Four raters were selected to assign a Koos grade to 50 total scans. Inter- and intrarater reliability were calculated and reported using Fleiss' kappa, Kendall's W, and Intraclass correlation coefficient (ICC). RESULTS: Inter-rater reliability was found to be substantial when measured using Fleiss' kappa (.71), extremely strong using Kendall's W (.92), and excellent as calculated by ICC (.88).Intrarater reliability was perfect for 3 out of 4 raters as assessed using weighted kappa, Kendall's W and ICC, with the intrarater agreement for the fourth rater measured as extremely high. CONCLUSION: We have demonstrated that the Koos classification system for vestibular schwannoma is a reliable method for tumor classification. This study lends further support to the results of current literature using Koos grading system. Further studies are required to evaluate its validity and utility in counseling patients with regard to outcomes.

Use of MRI in diabetic lumbosacral radiculoplexus neuropathy: case report and review of the literature.

Diabetic lumbosacral radiculoplexus neuropathy is often confused with radiculopathy in the context of spinal degenerative disc disease including spinal stenosis. Accuracy in diagnosis may prevent unnecessary interventional procedures including selective nerve root blocks or epidural steroid injections or even surgery in selected cases. Our patient with known diabetes and lumbar disc disease presented with acute onset of pain in L5-S1 distribution of the left lower extremity. Initial MR imaging of the lumbar spine did not show sufficient structural changes to explain her symptomatology. An MR neurogram of the lumbosacral plexus revealed inflammation within the bilateral sciatic and femoral nerves; subsequent EMG demonstrated a generalized sensorimotor neuropathy but no evidence of plexopathy. To our knowledge, this is the first case report that utilized MR imaging of the pelvis to assist in the diagnosis of diabetic lumbosacral radiculoplexus neuropathy (DLRPN).

Pineal cysts and other pineal region malignancies: determining factors predictive of hydrocephalus and malignancy.

OBJECTIVE Cystic lesions of the pineal gland are most often uncomplicated benign lesions with typical MRI characteristics. The authors aimed to study pineal lesion characteristics on MRI to better distinguish benign pineal cysts from other pineal region malignancies as well as to determine which characteristics were predictive of the latter malignancies. They also aimed to study risk factors predictive of hydrocephalus or malignancy in patients harboring these lesions. METHODS The authors performed a retrospective review of a prospectively compiled database documenting the outcomes of patients with suspected pineal cysts on MRI who had presented in the period from 1998 to 2004. Inherent patient and lesion characteristics were assessed in a univariate logistic regression analysis to predict the following dependent variables: development of hydrocephalus, biopsy-confirmed malignancy, and intervention. Possible inherent patient and lesion characteristics included age, sex, T1 and T2 MRI signal pattern, contrast enhancement pattern, presence of cyst, presence of blood, complexity of lesion, presence of calcification, and duration of follow-up. Inherent patient and lesion characteristics that were predictive in the univariate analysis (p < 0.15) were included in the multivariable logistic regression analysis. RESULTS Of the 79 patients with benign-appearing pineal cysts, 26 (33%) were male and 53 (67%) were female, with a median age of 38 years (range 9-86 years). The median cyst radius was 5 mm (range 1-20 mm). Two patients (2.5%) had evidence of calcifications, 7 (9%) had multicystic lesions, and 25 (32%) had some evidence of contrast enhancement. The median follow-up interval was 3 years (range 0.5-13 years). Seven patients (9%) had an increase in the size of their lesion over time. Eight patients (10%) had a hemorrhage, and 11 patients (14%) developed hydrocephalus. Nine (11%) received ventriculoperitoneal shunts for the development of hydrocephalus, and 12 patients (16%) were found to have malignancies following biopsy or resection. In the multivariate analysis, contrast enhancement on MRI (OR 1.6, 95% CI 2.86-74.74, p = 0.013) and hemorrhage (OR 26.9, 95% CI 3.4-212.7, p = 0.022) were predictive of hydrocephalus. Increasing lesion size and hydrocephalus were near perfect predictors of malignancy and thus were removed from multivariate analysis. In addition, contrast enhancement on MRI (OR 8.8, 95% CI 2.0-38.6, p = 0.004) and hemorrhage (OR 6.8, 95% CI 1.1-40.5, p = 0.036) were predictive of malignancy. CONCLUSIONS Although cystic abnormalities of the pineal gland are often benign lesions, they are frequently monitored over time, as other pineal region pathologies may appear similarly on MRI. Patients with growing lesions, contrast enhancement, and hemorrhage on MRI are more likely to develop hydrocephalus and have malignant pathology on histological examination and should therefore be followed up with serial MRI with a lower threshold for neurosurgical intervention.