Spine-Related Procedures

Neuraxial anesthesia types (i.e., epidural, spinal, and caudal anesthesia) are the most commonly used regional anesthetic techniques. These techniques not only provide means for anesthesia during surgery but also are commonly used for perioperative analgesia, in-labor analgesia, and chronic pain management. Preoperative evaluation is crucial and involves detailed history and examination as well as evaluation for contraindications. Different approaches are described and are dictated by a patient’s anatomy and medical condition. Midline is the most common approach used for spinal, epidural, and combined spinal epidural anesthesia. The paramedian approach has its advantages and can be used alternatively. The paramedian approach bypasses supraspinal and interspinal ligaments and provides direct access to the ligamentum flavum. The caudal epidural is commonly used in the pediatric population and chronic pain management. A transforaminal approach provides a more selective epidural spread in some painful conditions, such as lumbar radiculopathy and postlaminectomy syndrome. Axial low back pain due to facet arthropathy can be managed by facet joint injection or medial branch blocks, which are usually done under fluoroscopy. Ultrasound guidance is becoming more popular as it provides additional safety and improved accuracy during performance of regional anesthesia.

Anatomy of the Nervous System

Nociception, from the Latin noci (harm or injury), is the neural response to a noxious stimulus. It involves a four-part physiologic progression: transduction, transmission, modulation, and perception. This process results in the interpretation of pain, or “an unpleasant sensory and emotional experience associated with actual or potential tissue damage,” as defined by the International Association for the Study of Pain. Nociception occurs via a series of neurons, termed first, second, and third order, to signal an encounter with a painful stimulus from the periphery to the cerebral cortex. Neurotransmitters are released at synapses to relay both excitatory and inhibitory signals between neurons. First-order neurons are located in the dorsal root ganglion and synapse, with second-order neurons in the ipsilateral dorsal horn. Second-order neurons ascend the spinal cord, usually via the contralateral spinothalamic tract, then synapse with the third-order neurons in the thalamus. Third-order neurons finally transmit the signal to somatosensory areas I and II in the post–central gyrus of the parietal cortex or to the superior sylvian fissure.

Real-time Ultrasound-Guided Lumbar Epidural with Transverse Interlaminar View: Evaluation of an In-Plane Technique

OBJECTIVE

The anatomical landmarks method is currently the most widely used technique for epidural needle insertion and is faced with multiple difficulties in certain patient populations. Real-time ultrasound guidance has been recently used to aid in epidural needle insertion, with promising results. Our aim was to test the feasibility, success rate, and satisfaction associated with a novel real-time ultrasound-guided lumbar epidural needle insertion in the transverse interlaminar view.

DESIGN

Prospective descriptive trial on a novel approach.

SETTING

Operating room and preoperative holding area at a tertiary care hospital.

SUBJECTS

Adult patients presenting for elective open prostatectomy and planned for surgical epidural anesthesia.

METHODS

Consented adult patients aged 30-80 years scheduled for open prostatectomy under epidural anesthesia were enrolled. Exclusion criteria included allergy to local anesthetics, infection at the needle insertion site, coagulopathy, and patient refusal. A curvilinear low-frequency (2-5 MHz) ultrasound probe and echogenic 17-G Tuohy needles were used by one of three attending anesthesiologists. Feasibility of epidural insertion was defined as a 90% success rate within 10 minutes.

RESULTS

Twenty-two patients were enrolled into the trial, 14 (63.6%) of whom found the process to be satisfactory or very satisfactory. The median time to perform the block was around 4.5 minutes, with an estimated success rate of 95%. No complications related to the epidural block were observed over the 48 hours after the procedure.

CONCLUSIONS

We demonstrate the feasibility of a novel real-time ultrasound-guided epidural with transverse interlaminar view.

Real-time ultrasound-guided spinal anesthesia in patients with predicted difficult anatomy

BACKGROUND

There are limited reports of lumbar neuraxial blocks using real-time US in patients with predicted difficulties. We compared the number of attempts to perform spinal anesthesia using real-time US guidance versus landmark technique in patients meeting predefined criteria for difficult spinal anesthesia. We also compared procedure time, block success, patient satisfaction and difficulty scores between groups.

METHODS

Following institutional review board approval patients scheduled for total hip or knee arthroplasty with expected difficulty to perform spinal anesthesia were included. Number of attempts, block time, success rate, patient satisfaction and difficulty scores were recorded and we conducted the Kruskal-Wallis non-parametric test of difference between the groups.

RESULTS

Thirty-eight patients were enrolled and a total of 32 data sets was analyzed. For number of attempts, we observed no difference between the groups (P<0.83). The US group resulted in marginally higher time to block compared to the control (P<0.0653). The US group resulted in marginally higher satisfaction compared to the control group (P<0.09). The block success rate was 100% in both groups. Anesthesiologists rated the US group procedure more difficult than the control group (χ2=10.85, P<0.0010).

CONCLUSIONS

This trial suggests that real-time US guidance for spinal anesthesia in challenging patients in comparison to the controlled group was completed in longer time, with lower needle insertion attempts, and higher patient satisfaction scores but without statistically significant differences.

Continuous femoral nerve blocks: decreasing local anesthetic concentration to minimize quadriceps femoris weakness

BACKGROUND

Whether decreasing the local anesthetic concentration during a continuous femoral nerve block results in less quadriceps weakness remains unknown.

METHODS

Preoperatively, bilateral femoral perineural catheters were inserted in subjects undergoing bilateral knee arthroplasty (n = 36) at a single clinical center. Postoperatively, right-sided catheters were randomly assigned to receive perineural ropivacaine of either 0.1% (basal 12 ml/h; bolus 4 ml) or 0.4% (basal 3 ml/h; bolus 1 ml), with the left catheter receiving the alternative concentration/rate in an observer- and subject-masked fashion. The primary endpoint was the maximum voluntary isometric contraction of the quadriceps femoris muscles the morning of postoperative day 2. Equivalence of treatments would be concluded if the 95% CI for the difference fell within the interval -20%-20%. Secondary endpoints included active knee extension, passive knee flexion, tolerance to cutaneous electrical current applied over the distal quadriceps tendon, dynamic pain scores, opioid requirements, and ropivacaine consumption.

RESULTS

Quadriceps maximum voluntary isometric contraction for limbs receiving 0.1% ropivacaine was a mean (SD) of 13 (8) N · m, versus 12 (8) N · m for limbs receiving 0.4% [intrasubject difference of 3 (40) percentage points; 95% CI -10-17; P = 0.63]. Because the 95% CI fell within prespecified tolerances, we conclude that the effect of the two concentrations were equivalent. Similarly, there were no statistically significant differences in secondary endpoints.

CONCLUSIONS

For continuous femoral nerve blocks, we found no evidence that local anesthetic concentration and volume influence block characteristics, suggesting that local anesthetic dose (mass) is the primary determinant of perineural infusion effects.

Bilateral brachial plexus home going catheters after digital amputation for patient with upper extremity digital gangrene

Peripheral nerve catheter placement is used to control surgical pain. Performing bilateral brachial plexus block with catheters is not frequently performed; and in our case sending patient home with bilateral brachial plexus catheters has not been reported up to our knowledge. Our patient is a 57 years old male patient presented with bilateral upper extremity digital gangrene on digits 2 through 4 on both sides with no thumb involvement. The plan was to do the surgery under sequential axillary blocks. On the day of surgery a right axillary brachial plexus block was performed under ultrasound guidance using 20 ml of 0.75% ropivacaine. Patient was taken to the OR and the right fingers amputation was carried out under mild sedation without problems. Left axillary brachial plexus block was then done as the surgeon was closing the right side, two hours after the first block was performed. The left axillary block was done also under ultrasound using 20 ml of 2% mepivacaine. The brachial plexus blocks were performed in a sequential manner. Surgery was unremarkable, and patient was transferred to post anesthetic care unit in stable condition. Over that first postoperative night, the patient complained of severe pain at the surgical sites with minimal pain relief with parentral opioids. We placed bilateral brachial plexus catheters (right axillary and left infra-clavicular brachial plexus catheters). Ropivacaine 0.2% infusion was started at 7 ml per hour basal rate only with no boluses on each side. The patient was discharged home with the catheters in place after receiving the appropriate education. On discharge both catheters were connected to a single ON-Q (I-flow Corporation, Lake Forest, CA) ball pump with a 750 ml reservoir using a Y connection and were set to deliver a fixed rate of 7 ml for each catheter. The brachial plexus catheters were removed by the patient on day 5 after surgery without any difficulty. Patient's postoperative course was otherwise unremarkable. We concluded that home going catheters are very effective in pain control postoperatively and they shorten the period of hospital stay.

Chromosome Instability Associates with Radiation and Doxorubicin Resistance in Triple Negative Breast Cancer Cell Lines

BackgroundTriple negative (TN) breast cancers often have a worse prognosis, despite receiving appropriate chemotherapy and radiation treatment. Thus, one of the most pressing issues in breast cancer research is investigating the molecular basis for the inherent resistance of TN cells to standard of care treatment. Chromosome instability strongly associates with chemo-resistance and poor prognosis in breast cancer. We hypothesized that genetic heterogeneity imparted by chromosome instability provides the basis for chemotherapy and radiotherapy resistance in TN cells.MethodsFour TN cell lines (HS578, HCC1806, MB231, MB468) and a benign breast tissue line (MCF10) were treated with radiation or doxorubicin. The effects of the treatments were evaluated by the colony forming unit (CFU), MTT survival, Ki-67 immuno-histochemistry (IHC), caspase-3 IHC, micronuclei, and γ-H2AX assays.ResultsRadiation and Chemotherapy Dose Responses: Table I reveals the data from the CFU and MTT assays after treatment with radiation at 0, 1, 2, 4, 6, 8 Gy or doxorubicin at 0.5, 1, 2 μg/ml, respectively. The analyses revealed a range of sensitivities to radiation and doxorubicin, where HS578 was more sensitive to both treatments.Table I. Relative radio- and chemo-resistance of TN cell linesCell TypeTD 50 (Gy)IC50 (μg/ml)HS5781.60.31HCC18061.80.86MB4681.90.95MB2311.91.05MCF101.80.32 Apoptosis and Proliferation: Because the basis for chemo-and radio-resistance of TN cells may be uncontrolled proliferation frequencies and/or decreased apoptosis, proliferation assays (assessed by Ki-67 IHC), as well as apoptotic indexes (i.e. cleaved caspase 3) were performed. The Ki-67 assay showed that 2 Gy reduced proliferation by 13% in the HS578 line, but by only 2% with the MB231cells.After receiving 2 Gy, there was a wide range of apoptotic activity among the TN cell lines. The largest percentage of apoptosis occurred with the MB468 cells at 19% vs the lowest apoptotic activity seen with the HCC1806 line, 7%. Importantly, apoptotic activity was ≤ 7% when these cell lines were treated with 1 μg/ml of doxorubicin.Chromosome instability: The micronuclei and the γ-H2AX assays showed that 3 of the 4 TN cell lines harbored active genomic instability in the absence of doxorubicin or irradiation. The unstable TN cell lines had 15-30% γ-H2AX activity and 20-40% micronuclei formation, whereas the MCF10 and HCC1806 cells had approximately 11% γ-H2AX activity and 10% micronuclei present. To assess the molecular markers contributing to chromosome instability, we performed a real time PCR screen, as well as Western blot analyses of the cyclins, cyclin-dependent inhibitors and other signaling molecules that may contribute to chromosome instability. All cell lines that had high frequencies of chromosome instability had increased levels of cyclin D1, whereas a subset also de-regulated cyclin A.ConclusionOur results show that radio- and chemo- resistance in TN breast cancer cells closely associates with a de-regulated cell cycle and active chromosome instability. We conclude that the molecular basis for chromosome instability, chemotherapy and radiation resistance may be secondary to the unregulated expression of cyclins D1 and A.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1143.

The Triple Threat of Recurrence after Breast Conserving Therapy: Race, Receptor Status and Age

PurposeThe purpose of this study is to evaluate the impact of race, receptor status, and age on recurrence in patients undergoing breast conserving therapy (BCT).MethodsThe study population consisted of 510 primary invasive female breast cancer patients (excluding Stage IV), who resided in Fulton-Dekalb counties, in Atlanta, GA. These patients were diagnosed in 2003-2004 and treated within the Emory University Affiliated Hospitals. Data was obtained from the SEER cancer registry and augmented with medical record abstraction. Median follow-up was 3.5 and 4.4 years for recurrence and survival, respectively. Breast tumors were categorized as either triple negative (TN), which were estrogen, progesterone, and Her2-neu receptor negative tumors, versus (vs) non-TN, all other possible iterations. Women were evaluated for recurrence and death by TN status, race (African American (AA) vs Caucasian (C)), age, grade, tumor size, nodal status, socioeconomic status (SES), and receipt of chemotherapy. Both recurrence and survival were evaluated using chi-square, fisher exact, and cox regression analyses, p ≤ 0.05 significance.ResultsOf the 510 women, 193 received BCT. Of the 193, 92% completed radiation therapy and 45% received chemotherapy. Of the 184 women with known recurrence status, 11 recurred locally, 11 distantly, and none regionally. Compared to patients with non-TN tumors, TN patients had significantly higher local (13% vs 5%) and distant (16% vs 4%) recurrence rates. AA women had non-significant higher local recurrence than C women (7% vs 4%) and a higher distant recurrence rate (8% vs 3%). Finally, compared to women ≥50 years old, women age &lt;50 had a significantly higher local and distant recurrence rates, (13% vs 4%) and (9% vs 5%) respectively.Unadjusted hazard ratios (HR) and 95% confidence intervals (CI) for any recurrence were calculated: TN status (HR=2.8, 95%CI 1.2-6.5), AA race (HR=2.3, 95% CI 0.9-5.8), age &lt;50 years (HR= 2.3, 95%CI 1.0-5.1), grade 2/3 vs 1 (HR=2.3, 95%CI 1.0-5.1), and chemotherapy receipt (HR=3.0, 95%CI 1.2-7.4). Factors that were highly non-statistically significant included stage, tumor size, nodal status, and SES.In a multivariate model including receptor status, race, and age results were similar (HR = 2.5, 2.1, and 2.1 respectively). When tumor size, nodal status, grade, SES, and chemotherapy status were included in the previous model, only AA race independently predicted recurrence (HR=3.4, 95%CI 1.1-11.1), while TN status demonstrated a trend (HR=1.9, 95%CI 0.8-5.7).In survival analyses, neither TN status, AA race, nor age &lt;50 years predicted outcome in any of the models described above. However, TN status did show a trend for significance (HR=2.6, 95%CI 0.8-9.0).ConclusionWe observed that there was a significant increase in local and distant metastatic recurrence rates after BCT among patients diagnosed with TN breast cancers, AA women, and women &lt;50 years old. In contrast, we did not observe differences in survival, with the exception of TN breast cancers. This study suggests that among women who receive BCT, current standard radiation and systemic therapies may not be adequate in preventing recurrence among women with TN breast cancers, of AA race, or younger age.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6045.

Cytokine control of parasite-specific anergy in human urinary schistosomiasis. IL-10 modulates lymphocyte reactivity

Humans chronically infected with schistosomiasis usually have impaired parasite Ag-specific lymphocyte proliferation and IFN-gamma production that may facilitate persistence of the parasite while producing little clinical disease. The mechanisms that contribute to the immunologic hyporesponsiveness in these patients remain undefined. IL-10 has been shown to exert an inhibitory effect on cell-mediated immunity. To determine whether endogenous IL-10 has a role in regulating parasite-specific anergy in schistosomiasis, neutralizing anti-IL-10 added to PBMC from Schistosoma haematobium patients' enhanced adult worm (SWAP)- or egg Ag (SEA)-driven lymphocyte proliferation and/or IFN-gamma production by 2- to &gt;100-fold in 32 of 38 subjects. In contrast, anti-IL-10 failed to significantly augment the mycobacterial Ag, purified protein derivative (PPD)-driven lymphocyte proliferation, or IFN-gamma production in 9 or 10 of 14 individuals, respectively. SWAP or SEA triggered IL-10 release from PBMC of both patients and healthy individuals; however, CD4+ cells were a significant source of IL-10 only in infected subjects. PPD relative to SWAP induced fivefold less IL-10 release by CD4+ cells (p &lt; 0.01). A possible mechanism whereby IL-10 suppressed Ag-specific T cell responses was demonstrated by the ability of SWAP and not PPD to suppress B7 expression on PBMC. Anti-IL-10 completely inhibited the parasite Ag-induced down-regulation of B7 expression. These studies indicate that IL-10 contributes to parasite Ag-induced T cell hyporesponsiveness observed in patients with chronic schistosomiasis hematobia.

Cytokine control of parasite-specific anergy in human urinary schistosomiasis. IL-10 modulates lymphocyte reactivity

Humans chronically infected with schistosomiasis usually have impaired parasite Ag-specific lymphocyte proliferation and IFN-gamma production that may facilitate persistence of the parasite while producing little clinical disease. The mechanisms that contribute to the immunologic hyporesponsiveness in these patients remain undefined. IL-10 has been shown to exert an inhibitory effect on cell-mediated immunity. To determine whether endogenous IL-10 has a role in regulating parasite-specific anergy in schistosomiasis, neutralizing anti-IL-10 added to PBMC from Schistosoma haematobium patients' enhanced adult worm (SWAP)- or egg Ag (SEA)-driven lymphocyte proliferation and/or IFN-gamma production by 2- to >100-fold in 32 of 38 subjects. In contrast, anti-IL-10 failed to significantly augment the mycobacterial Ag, purified protein derivative (PPD)-driven lymphocyte proliferation, or IFN-gamma production in 9 or 10 of 14 individuals, respectively. SWAP or SEA triggered IL-10 release from PBMC of both patients and healthy individuals; however, CD4+ cells were a significant source of IL-10 only in infected subjects. PPD relative to SWAP induced fivefold less IL-10 release by CD4+ cells (p < 0.01). A possible mechanism whereby IL-10 suppressed Ag-specific T cell responses was demonstrated by the ability of SWAP and not PPD to suppress B7 expression on PBMC. Anti-IL-10 completely inhibited the parasite Ag-induced down-regulation of B7 expression. These studies indicate that IL-10 contributes to parasite Ag-induced T cell hyporesponsiveness observed in patients with chronic schistosomiasis hematobia.