Broad and Asymmetric Lower Extremity Myotomes: Results from Intraoperative Direct Electrical Stimulation of the Lumbosacral Spinal Roots.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: This study aimed to accurately map the lower extremity muscles innervated by the lumbar spinal roots by directly stimulating the spinal roots during surgery. SUMMARY OF BACKGROUND DATA: Innervation of the spinal roots in the lower extremities has been estimated by clinical studies, anatomical studies, and animal experiments. However, there have been discrepancies between studies. Moreover, there are no studies that have studied the laterality of lower limb innervation. MATERIALS AND METHODS: In 73 patients with lumbar degenerative disease, a total of 147 spinal roots were electrically stimulated and the electromyographic response was recorded at the vastus medialis (VM), gluteus medius (GM), tibialis anterior (TA), biceps femoris (BF), and gastrocnemius (GC). The asymmetry index (AI) was obtained using the following equation to represent the left-right asymmetry in the CMAP amplitude. Paired t-tests were used to compare CMAP amplitudes on the right and left sides. Differences in the AI among the same spinal root groups were determined using one-way analysis of variance. RESULTS: The frequency of compound muscle action potentials (CMAP) elicitation in VM, GM, TA, BF, and GC were 100%, 75.0%, 50.0%, 83.3%, and 33.3% in L3 spinal root stimulation, 90.4%, 78.8%, 59.6%, 73.1%, and 59.6% in L4 spinal root stimulation, 32.2%, 78.0%, 93.2%, 69.5%, and 83.1% in L5 spinal root stimulation, and 40.0%, 100%, 80.0%, 70.0%, and 80.0% in S1 spinal root stimulation, respectively. The most frequent muscle with maximum amplitude of the CMAP in L3, L4, L5, and S1 spinal root stimulation was the VM, GM, TA, and GM respectively. Unilateral innervation occurred at high rates in the TA in L4 root stimulation and the VM in L5 root stimulation in 37.5% and 42.3% of patients, respectively. Even in patients with bilateral innervation, a 20-38% asymmetry index of CMAP amplitude was observed. CONCLUSIONS: The spinal roots innervated a much larger range of muscles than what is indicated in general textbooks. Furthermore, a non-negligible number of patients showed asymmetrical innervation of lower limb by the lumbar spinal roots.

Improvement of predicted hematocrit values after the initiation of cardiopulmonary bypass in cardiovascular surgery.

Hematocrit (Hct) values after the initiation of cardiopulmonary bypass (CPB) must be maintained appropriately to avoid perioperative complications. Therefore, an accurate prediction is required. However, the standard prediction equation often results in actual values that are lower than the predicted values. This study aimed to clarify the limits of agreement (LOA) and bias of the prediction equations and investigate better the prediction equations. A retrospective study was performed on adult patients between April 2015 and December 2020. Study 1 included 158 patients, and Study 2 included 55 patients. The primary outcomes were the LOA and bias between the predicted and measured Hct values after the initiation of CPB, and two studies were conducted. In Study 1, total blood volume (TBV) was estimated, and the new blood volume index (BVI) was calculated. BVI was also evaluated for the overall value and gender differences. Therefore, the patient's background was compared by gender differences. In, Study 2 the conventional predicted equation (Eq. 1), the predicted equation using the new BVI (Eq. 2), and the predicted equation using the new BVI including physiological factors in the TBV equation (Eq. 3) were compared. In Study 1, BVI was 53 (44-67) mL/kg. In Study 2, bias ± LOA was - 2.5 ± 6.8% for Eq. 1, 0.1 ± 6.6% for Eq. 2, and 0.4 ± 6.2% for Eq. 3. The new equation is expected to predict the Hct value after the initiation of CPB with better LOA and bias than the conventional equation.

Early induction of direct hemoperfusion with a polymyxin-B immobilized column is associated with amelioration of hemodynamic derangement and mortality in patients with septic shock.

This study was conducted to clarify the effectiveness of induction timing of direct hemoperfusion with a polymyxin-B immobilized column (PMX-DHP) for amelioration of hemodynamic derangement and outcome in patients with septic shock. Suspected Gram-negative septic shock patients who received PMX-DHP therapy from January 2010 to December 2014 in our ICU were enrolled in this study. The patients were divided into two groups that received PMX-DHP therapy within 8 h (early group) and more than 8 h (late group) from catecholamine administration. Changes in catecholamine dose [catecholamine index (CAI)], catecholamine dose/mean arterial pressure [catecholamine index pressure (CAIP)], PaO2/FiO2 and PEEP level were determined at the start of and 24 h after the start of PMX-DHP therapy. Ventilator-free days (VFD), ICU-free days (IFD), 28-day and hospital mortality were also determined. There were no significant differences in patients' characteristics between the two groups. CAI and CAIP were significantly decreased in the early group. PaO2/FiO2 was not changed whereas PEEP level in the early group was significantly decreased during PMX-DHP therapy. IFD and VFD were not different in the two groups. Mortality at 28 days was significantly improved in the early group. Endotoxin acts as an early mediator in sepsis patients with suspected Gram-negative infection. Earlier induction of PMX-DHP therapy as in our study is closely associated with earlier weaning from hemodynamic derangement and with improvement of mortality. Therefore, early induction of PMX-DHP therapy is recommended for the treatment of septic shock in patients with presumed Gram-negative infection.

Efficacy of intraoperative direct electrical stimulation of the spinal root and measurement of distal motor latency in lumbar spinal stenosis.

PURPOSE: The measurement of distal motor latency (DML) is an established method for diagnosing entrapment peripheral neuropathy. DML can also serve as an index for disease severity and prognosis. We considered that measuring DML could be useful in estimating the severity of spinal root impairment and predicting prognosis in patients with lumbar spinal stenosis (LSS). The purpose of this study was to investigate the efficacy of intraoperative direct electrical stimulation of the spinal root and the measurement of DML in LSS. METHODS: In 39 patients with LSS, a total of 93 spinal roots were stimulated, and evoked electromyography was recorded at the leg muscles after decompression. DML was measured and its correlation with clinical severity, as evaluated by Zurich claudication questionnaire (ZCQ) and Short Form 36 (SF-36), was investigated. RESULTS: For the stimulation of the L3, L4, and L5 spinal root, the mean DML (ms) were 6.8 (±1.4), 7.4 (±1.3), and 6.0 (±1.3) in gluteus medius, 9.3 (±1.5), 9.2 (±1.5), and 9.0 (±1.6) in biceps femoris, 9.7 (±1.0), 9.8 (±1.8), and 9.4 (±1.2) in vastus medialis, 16.1 (±1.0), 14.7 (±1.3), and 14.1 (±1.5) in tibialis anterior, and 16.4 (±1.4), 14.3 (±1.8), and 13.9 (±1.9) in gastrocnemius muscles. Statistically significant positive correlations were observed between DML and height. Preoperative symptom and function scores of ZCQ and postoperative bodily pain scores of SF-36 were significantly worse in the patients with prolonged DML. CONCLUSIONS: DML is thought to be useful for estimating the severity of spinal root impairment and for predicting the prognosis.