The effect of impaired unilateral ankle propulsion on contralateral knee joint loading.

BACKGROUND: Impairments in unilateral ankle propulsion may result from restriction by an external device or pathology such as lower limb amputation. Models of gait suggest this reduction may lead to increased collisional force on the contralateral side, potentially increasing force through the knee and increasing the risk of knee pain or osteoarthritis. RESEARCH QUESTION: How do restrictions in unilateral ankle propulsive force affect contralateral knee joint loading in otherwise healthy individuals? METHODS: 18 individuals without impairment walked on a treadmill at 1.5 m/s for two conditions: one free of restrictions, and one where a randomized limb's ankle propulsive force was restricted using an off-the-shelf ankle-foot orthosis (AFO). Ankle propulsive power, lower extremity joint work, and ground reaction force variables were calculated for the final 3 gait cycles of each condition. Tibiofemoral joint contact force (TJCF) for the limb contralateral to the AFO was calculated through a standard OpenSim workflow utilizing the gait2392 model. Intra-limb pair-wise comparisons were made between conditions. RESULTS: Compared to walking unrestricted, the limb wearing the AFO demonstrated a significant reduction in peak ankle propulsive power and positive ankle work by approximately 50 % each (p<0.01). With ankle restriction, the ipsilateral knee significantly increased positive work (p<0.01). The overall propulsion produced by that limb did not change between conditions, demonstrated by a lack of change in anterior ground reaction force impulse (p=0.11). The knee of the limb contralateral to the AFO did not display differences in any TJCF variable between conditions (all p>0.07). SIGNIFICANCE: These results suggest a unilateral deficit in ankle propulsion will not increase contralateral knee joint forces in individuals who are able to use other joints of the limb to compensate for the loss of ankle function. However, further research should investigate this relationship in those who display pathologies that may prevent more proximal compensations.

Single Session Effects of Prolonged Continuous Theta Burst Stimulation Targeting Two Brain Regions on Pain Perception in Patients with Painful Diabetic Neuropathy: A Preliminary Study.

BACKGROUND: Painful diabetic neuropathy (pDN) is the most common cause of neuropathic pain (NP) in the United States. Prolonged continuous theta burst stimulation (pcTBS), a form of repetitive transcranial magnetic stimulation (rTMS), is quick (1-4 minutes) and tolerable for most individuals, compared to high frequency rTMS and can modulate pain thresholds in healthy participants. However, its effects on patients with chronic pain are still unclear. The primary purpose of this preliminary study is to investigate the effects of single session pcTBS targeted at the primary motor cortex (M1) and dorsolateral prefrontal cortex (DLPFC) on a set of self-report measures of pain (SRMP) that assess the (a) sensory-discriminative; (b) affective-motivational; and (c) cognitive-evaluative aspects of pain experience. METHODS: For this prospective, single-blind study, forty-two participants with pDN were randomized to receive either pcTBS targeting the M1 or the DLPFC brain regions. SRMP were completed at baseline, post pcTBS and 24h-post pcTBS. A two-way mixed model repeated measures analysis of variance (2 brain regions by 3 time points) was conducted to evaluate the effects of pcTBS stimulation at M1 and DLPFC for each subscale of each SRMP. RESULTS: After a single session of pcTBS targeted at M1 or DLPFC in patients with pDN, statistically significant improvements from baseline to post pcTBS and baseline to 24 h-post pcTBS were observed for different SRMP subscales examining the (a) sensory-discriminative, (b) affective-motivational and (c) cognitive-evaluative components of the pain experience. At 24 h-post pcTBS, none of the participants reported any serious adverse events to the pcTBS treatment, thus demonstrating its feasibility. CONCLUSIONS: In pDN patients with NP, our study results demonstrated significant improvement in scores on self-report measures of pain (SRMP) after a single session of pcTBS targeting the M1 and DLPFC brain regions. Future studies should consider utilizing multiple sessions of pcTBS to evaluate its long-term effects on pain perception, safety and tolerability in patients with chronic pain. CLINICAL TRIAL REGISTRATION: This study was registered on the ClinicalTrials.gov website (NCT04988321).

Lending a hand: The utility of hand-assisted laparoscopic surgery in diverticulitis with fistula.

BACKGROUND: Current guidelines recommend elective colectomy for the management of diverticulitis-associated fistulas. These cases present considerable operative challenges, and surgical approaches and fistula tract management vary widely. Hand-assisted laparoscopic surgery offers the benefits of minimally invasive surgery while maintaining the tactile advantages of open surgery. This study aims to evaluate outcomes of hand-assisted laparoscopic surgery colectomy for diverticulitis-associated fistulas, fistula tract, and urinary catheter management. METHODS: A retrospective review of patients with diverticulitis-associated fistula who underwent elective hand-assisted laparoscopic surgery colectomy between January 2, 2008, and September 8, 2022, was performed. Patients with Crohn disease or who underwent emergency surgery were excluded. RESULTS: Seventy patients were included; the mean patient age was 64.1 ± 14.8 years, and the mean body mass index was 30.9 ± 9.1 kg/m2. Colovesical fistulas were most common (n = 48; 68.6%), followed by colovaginal fistulas (n = 22; 31.4%). The median operative time was 186 minutes. Conversion to an open approach occurred in 4 cases (5.7%). The fistula tract remnant was left without intervention in 35 patients (50%), and omental coverage occurred in 23 cases (32.9%). The median duration of the urinary catheter was 3 days (range = 1-63). There were no postoperative urine leaks. Three patients (4.3%) were readmitted in ≤30 days. There were no 30-day mortalities. CONCLUSION: The challenges of colectomy for diverticulitis-associated fistulas can be mitigated using the hand-assisted laparoscopic surgery technique. We found a low conversion-to-open rate, falling below rates reported for laparoscopic colectomy. There were no cases of postoperative urine leak, suggesting that no intervention or omental coverage is a safe approach to fistula tract management.

Evaluation of the Rothman Index in Predicting Readmission after Colorectal Resection.

The Rothman Index (RI) is a real-time health indicator score that has been used to quantify readmission risk in several fields but has never been studied in gastrointestinal surgery. In this retrospective single-institution study, the association between RI scores and readmissions after unplanned colectomy or proctectomy was evaluated in 427 inpatients. Patient demographics and perioperative measures, including last RI, lowest RI, and increasing/decreasing RI score, were collected. In the selected cohort, 12.4% of patients were readmitted within 30 days of their initial discharge. Last RI, lowest RI, decreasing RI, and increasing RI scores remained significant after controlling for covariates in separate multivariate regression analyses. The last RI score at the time of discharge was found to be the most strongly associated with 30-day readmission risk following colorectal resection. These findings support the RI as a potential tool in the inpatient management of postoperative patients to identify those at high risk of readmission.

Anorectal Emergencies.

Anorectal emergencies are rare presentations of common anorectal disorders, and surgeons are often called on to assist in their diagnosis and management. Although most patients presenting with anorectal emergencies can be managed nonoperatively or with a bedside procedure, surgeons must also be able to identify surgical anorectal emergencies, such as gangrenous rectal prolapse. This article provides a review of pertinent anatomy; examination techniques; and workup, diagnosis, and management of common anorectal emergencies including thrombosed hemorrhoids, incarcerated hemorrhoids, anal fissure, anorectal abscess, rectal prolapse, and pilonidal abscess and unique situations including rectal foreign body and anorectal sexually transmitted infections.

Prolonged continuous theta burst stimulation increases motor corticospinal excitability and intracortical inhibition in patients with neuropathic pain: An exploratory, single-blinded, randomized controlled trial.

OBJECTIVES: A new paradigm for Transcranial Magnetic Stimulation (TMS), referred to as prolonged continuous theta burst stimulation (pcTBS), has recently received attention in the literature because of its advantages over high frequency repetitive TMS (HF-rTMS). Clinical advantages include less time per intervention session and the effects appear to be more robust and reproducible than HF-rTMS to modulate cortical excitability. HF-rTMS targeted at the primary motor cortex (M1) has demonstrated analgesic effects in patients with neuropathic pain but their mechanisms of action are unclear and pcTBS has been studied in healthy subjects only. This study examined the neural mechanisms that have been proposed to play a role in explaining the effects of pcTBS targeted at the M1 and DLPFC brain regions in neuropathic pain (NP) patients with Type 2 diabetes. METHODS: Forty-two patients with painful diabetic neuropathy were randomized to receive a single session of pcTBS targeted at the left M1 or left DLPFC. pcTBS stimulation consisted of 1,200 pulses delivered in 1 min and 44 s with a 35-45 min gap between sham and active pcTBS stimulation. Both the activity of the descending pain system which was examined using conditioned pain modulation and the activity of the ascending pain system which was assessed using temporal summation of pain were recorded using a handheld pressure algometer by measuring pressure pain thresholds. The amplitude of the motor evoked potential (MEP) was used to measure motor corticospinal excitability and GABA activity was assessed using short (SICI) and long intracortical inhibition (LICI). All these measurements were performed at baseline and post-pcTBS stimulation. RESULTS: Following a single session of pcTBS targeted at M1 and DLPFC, there was no change in BPI-DN scores and on the activity of the descending (measured using conditioned pain modulation) and ascending pain systems (measured using temporal summation of pain) compared to baseline but there was a significant improvement of >13% in perception of acute pain intensity, increased motor corticospinal excitability (measured using MEP amplitude) and intracortical inhibition (measured using SICI and LICI). CONCLUSION: In patients with NP, a single session of pcTBS targeted at the M1 and DLPFC modulated the neurophysiological mechanisms related to motor corticospinal excitability and neurochemical mechanisms linked to GABA activity, but it did not modulate the activity of the ascending and descending endogenous modulatory systems. In addition, although BPI-DN scores did not change, there was a 13% improvement in self-reported perception of acute pain intensity.

Management of Immunotherapy Infusion Reactions.

Indications for the use of immunotherapy in oncology are increasing rapidly. Each classification of immunotherapy has its own unique characteristics. Understanding the mechanism of action and the potential for infusion reacti.

Going for Broke: The Impact of Cost of Living on Surgery Resident Stipend Value.

OBJECTIVE: The objective of this study was to provide a direct comparison of first-year general surgery resident stipends across states and major cities, using the Cost-of-Living Index (COLI) to determine stipend value. BACKGROUND: Financial challenges are among residents' top sources of stress, and this may be exacerbated in areas with high costs of living. A 2021 survey found that the mean first-year medical resident stipend increased by 0.6%, or $358, from 2020 to 2021, and only 33% of institutions used cost-of-living to determine annual resident stipend adjustments. METHODS: An American Medical Association database was used to identify accredited general surgery residency programs. The 2021-2022 stipend data for first-year general surgery positions were obtained, then data were grouped by state and major city and averaged. Major cities were defined as cities with >4 programs.A direct comparison of stipends was performed using the COLI. RESULTS: Stipend data were available for 337 of 346 general surgery programs. The national average first-year residency stipend was $60,064±$4233. The average COLI-adjusted stipend was $57,090±$5742, with a value loss of -$3493, or 5%.For major cities, the average stipend was $63,383±$4524, and the average COLI-adjusted stipend was $46,929±$8383, with an average value loss of -$16,454, or 26%. CONCLUSIONS: The financial burdens that residents face cannot be overlooked, and the cost of living has a meaningful impact on resident stipend value. The current Graduate Medical Education compensation structure limits federal and institutional capacity to adjust for the cost of living and creates an insulated market in which residents are under-compensated.

The WHO European framework for action to achieve the highest attainable standard of health for persons with disabilities 2022-2030.

There are approximately 135 million persons with disabilities in the WHO European Region. In order to address health inequities experienced by this population, Member States and WHO/Europe developed the 'WHO European framework for action to achieve the highest attainable standard of health for persons with disabilities 2022-2030', in close cooperation with organisations of persons with disabilities. The Framework, with its accompanying Resolution, was adopted by all 53 Member States in September 2022. The Framework is aligned with the core priorities of the WHO European Programme of Work 2020-2025, that is, achieving universal health coverage, protecting against health emergencies, and promoting health and well-being. It consists of four objectives, 13 targets, and 20 indicators that act as measures of progress and success, and as drivers for policy action and a roadmap for Member States towards a disability-inclusive health sector. The Framework is expected to have a significant impact on the health and well-being of all in the Region, and especially persons with disabilities, as it will advance inclusive health systems across the Region. Inclusive health sectors will aid towards the achievement of the Sustainable Development Goals, the protection of the human rights of persons with disabilities, and the promotion of their health.

Predicting Neoadjuvant Treatment Response in Rectal Cancer Using Machine Learning: Evaluation of MRI-Based Radiomic and Clinical Models.

BACKGROUND: Radiomics is an approach to medical imaging that quantifies the features normally translated into visual display. While both radiomic and clinical markers have shown promise in predicting response to neoadjuvant chemoradiation therapy (nCRT) for rectal cancer, the interrelationship is not yet clear. METHODS: A retrospective, single-institution study of patients treated with nCRT for locally advanced rectal cancer was performed. Clinical and radiomic features were extracted from electronic medical record and pre-treatment magnetic resonance imaging, respectively. Machine learning models were created and assessed for complete response and positive treatment effect using the area under the receiver operating curves. RESULTS: Of 131 rectal cancer patients evaluated, 68 (51.9%) were identified to have a positive treatment effect and 35 (26.7%) had a complete response. On univariate analysis, clinical T-stage (OR 0.46, p = 0.02), lymphovascular/perineural invasion (OR 0.11, p = 0.03), and statin use (OR 2.45, p = 0.049) were associated with a complete response. Clinical T-stage (OR 0.37, p = 0.01), lymphovascular/perineural invasion (OR 0.16, p = 0.001), and abnormal carcinoembryonic antigen level (OR 0.28, p = 0.002) were significantly associated with a positive treatment effect. The clinical model was the strongest individual predictor of both positive treatment effect (AUC = 0.64) and complete response (AUC = 0.69). The predictive ability of a positive treatment effect increased by adding tumor and mesorectal radiomic features to the clinical model (AUC = 0.73). CONCLUSIONS: The use of a combined model with both clinical and radiomic features resulted in the strongest predictive capability. With the eventual goal of tailoring treatment to the individual, both clinical and radiologic markers offer insight into identifying patients likely to respond favorably to nCRT.

Paired pulse transcranial magnetic stimulation in the assessment of biceps voluntary activation in individuals with tetraplegia.

After spinal cord injury (SCI), motoneuron death occurs at and around the level of injury which induces changes in function and organization throughout the nervous system, including cortical changes. Muscle affected by SCI may consist of both innervated (accessible to voluntary drive) and denervated (inaccessible to voluntary drive) muscle fibers. Voluntary activation measured with transcranial magnetic stimulation (VATMS) can quantify voluntary cortical/subcortical drive to muscle but is limited by technical challenges including suboptimal stimulation of target muscle relative to its antagonist. The motor evoked potential (MEP) in the biceps compared to the triceps (i.e., MEP ratio) may be a key parameter in the measurement of biceps VATMS after SCI. We used paired pulse TMS, which can inhibit or facilitate MEPs, to determine whether the MEP ratio affects VATMS in individuals with tetraplegia. Ten individuals with tetraplegia following cervical SCI and ten non-impaired individuals completed single pulse and paired pulse VATMS protocols. Paired pulse stimulation was delivered at 1.5, 10, and 30 ms inter-stimulus intervals (ISI). In both the SCI and non-impaired groups, the main effect of the stimulation pulse (paired pulse compared to single pulse) on VATMS was not significant in the linear mixed-effects models. In both groups for the stimulation parameters we tested, the MEP ratio was not modulated across all effort levels and did not affect VATMS. Linearity of the voluntary moment and superimposed twitch moment relation was lower in SCI participants compared to non-impaired. Poor linearity in the SCI group limits interpretation of VATMS. Future work is needed to address methodological issues that limit clinical application of VATMS.

The assessment of biceps voluntary activation with transcranial magnetic stimulation in individuals with tetraplegia.

BACKGROUND: Assessment of voluntary activation is useful in the study of neuromuscular impairments, particularly after spinal cord injury (SCI). Measurement of voluntary activation with transcranial magnetic stimulation (VATMS) is limited by technical challenges, including the difficulty in preferential stimulation of cortical neurons projecting to the target muscle and minimal stimulation of antagonists. Thus, the motor evoked potential (MEP) response to TMS in the target muscle compared to its antagonist may be an important parameter in the assessment of VATMS. OBJECTIVE: The purpose of this study was to evaluate the effect of isometric elbow flexion angle on two metrics in individuals with tetraplegia following SCI: 1) the ratio of biceps/triceps MEP amplitude across a range of voluntary efforts, and 2) VATMS. METHODS: Ten individuals with tetraplegia and ten nonimpaired individuals were recruited to participate in three sessions wherein VATMS was assessed at 45°, 90°, and 120° of isometric elbow flexion. RESULTS: In SCI participants, the biceps/triceps MEP ratio was not modulated by elbow angle. In nonimpaired participants, the biceps/triceps MEP ratio was greater in the more flexed elbow angle (120° flexion) compared to 90° during contractions of 50% and 75% MVC, but VATMS was not different. VATMS assessed in the more extended elbow angle (45° flexion) was lower relative to 90° elbow flexion; this effect was dependent on the biceps/triceps MEP ratio. In both groups, VATMS was sensitive to the linearity of the voluntary moment and superimposed twitch relationship, regardless of elbow angle. Linearity was lower in SCI relative to nonimpaired participants. CONCLUSIONS: Increasing the MEP ratio via elbow angle did not enable estimation of VATMS in SCI participants. VATMS may not be a viable approach to assess neuromuscular function in individuals with tetraplegia.

Effects of stimulus waveform on transcranial magnetic stimulation metrics in proximal and distal arm muscles.

OBJECTIVES: The purpose of this study was to determine the effect of common transcranial magnetic stimulation (TMS) waveforms (monophasic and biphasic) on resting motor threshold (RMT), active motor threshold (AMT), and motor evoked potential (MEP) amplitudes in the biceps and first dorsal interosseous (FDI) because waveforms may affect motor targets differently. We also determined test-retest reliability. METHODS: Ten individuals participated in two sessions of TMS delivered to the motor cortex. Monophasic stimulation to induce a posterior-anterior current in the brain (monoPA) and biphasic posterior-anterior then anterior-posterior (biPA-AP) were applied in each session in random order. In each session, there were four blocks of measurements (2 muscles × 2 waveforms) of RMT, AMT and MEPs at the hotspot location. MEPs were normalized to the maximum EMG signal. RESULTS: RMTs and AMTs were lower for monoPA compared to biPA-AP stimulation for the biceps (p<0.01) and FDI (p<0.01). Normalized MEPs were greater for monoPA compared to biPA-AP stimulation in the FDI (p=0.01) and not different in the biceps (p=0.86). Motor thresholds were not different between sessions suggesting high reliability (p<0.01). Normalized MEPs had very low reliability across sessions in the FDI, and moderate reliability in the biceps. DISCUSSION: Preliminary investigation suggests the effect of TMS waveform on motor thresholds is similar in upper limb proximal and distal muscles, but the effect differs per motor target for MEPs. Further, test-retest reliability of waveform effects was sensitive to target muscle. These findings may contribute to improve the efficacy and reliability of TMS for clinical use.

Intermittent theta burst stimulation modulates biceps brachii corticomotor excitability in individuals with tetraplegia.

BACKGROUND: Intermittent theta burst stimulation (iTBS) is a form of repetitive transcranial magnetic stimulation (TMS) that can increase corticomotor excitability of hand muscles in individuals with spinal cord injury (SCI). The objective of this study was to determine the effect of iTBS on the corticomotor excitability of the biceps brachii in individuals with tetraplegia. METHODS: Ten individuals with low cervical SCI (C5-C8) and ten nonimpaired individuals completed three independent sessions. Motor evoked potentials (MEPs) served as our measure of corticomotor excitability and were collected before and after iTBS. MEPs were normalized by the electromyography corresponding to maximum voluntary contraction and analyzed using linear mixed effects models to determine the effect of iTBS (active or sham) on normalized MEPs (nMEPs). iTBS effects were compared to a ratio of active and resting motor thresholds as a measurement of corticomotor conductance potential. RESULTS: Relative to sham, active iTBS increased nMEPs over time (p < 0.001) in individuals with SCI, but not nonimpaired individuals (p = 0.915). The amplitude of nMEPs were correlated with the biceps corticomotor conductance potential (p < 0.001), with nMEPs decreasing as the ratio increased at different rates after sham or active iTBS. CONCLUSIONS: Preliminary results suggest that iTBS increases biceps corticomotor excitability in individuals with tetraplegia with effects that may be predicted by corticomotor conductance potential. Clinical trial registration NCT03277521 Registered on clinicaltrials.gov on August 24, 2017.

Effect of neuroanatomy on corticomotor excitability during and after transcranial magnetic stimulation and intermittent theta burst stimulation.

Individual neuroanatomy can influence motor responses to transcranial magnetic stimulation (TMS) and corticomotor excitability after intermittent theta burst stimulation (iTBS). The purpose of this study was to examine the relationship between individual neuroanatomy and both TMS response measured using resting motor threshold (RMT) and iTBS measured using motor evoked potentials (MEPs) targeting the biceps brachii and first dorsal interosseus (FDI). Ten nonimpaired individuals completed sham-controlled iTBS sessions and underwent MRI, from which anatomically accurate head models were generated. Neuroanatomical parameters established through fiber tractography were fiber tract surface area (FTSA), tract fiber count (TFC), and brain scalp distance (BSD) at the point of stimulation. Cortical magnetic field induced electric field strength (EFS) was obtained using finite element simulations. A linear mixed effects model was used to assess effects of these parameters on RMT and iTBS (post-iTBS MEPs). FDI RMT was dependent on interactions between EFS and both FTSA and TFC. Biceps RMT was dependent on interactions between EFS and and both FTSA and BSD. There was no groupwide effect of iTBS on the FDI but individual changes in corticomotor excitability scaled with RMT, EFS, BSD, and FTSA. iTBS targeting the biceps was facilitatory, and dependent on FTSA and TFC. MRI-based measures of neuroanatomy highlight how individual anatomy affects motor system responses to different TMS paradigms and may be useful for selecting appropriate motor targets when designing TMS based therapies.

An AP Perspective on Infusion Reactions in the Era of Immunotherapy.

As cancer care advances, creative uses for immunotherapy continue to be developed, but it is also important to be cognizant of the risk for infusion reactions. At JADPRO Live Virtual 2021, Carrie Peterson, DNP, RN, AGNP-c, reviewed the different classes and pathophysiology of immunotherapy, how to anticipate potential infusion reactions for each class of immunotherapy, and how to identify and treat infusion reactions during infusion of immunotherapy so that patients can stay on treatment.

Long term clinical outcomes and associated predictors of progression free survival in anal canal cancer.

Background: Reports of long term clinical outcomes for patients with squamous cell carcinoma (SCC) of the anal canal treated with chemotherapy and intensity modulated radiation therapy (IMRT) are limited. Pre-treatment hematologic variables associated with outcomes remain understudied. We sought to report the long-term clinical outcomes of a cohort of patients treated with definitive chemoradiation (CRT) utilizing helical tomotherapy (HT) IMRT at a single tertiary referral center. We further sought to examine for any correlations between pre-treatment hematologic parameters and progression free survival (PFS). Methods: Data from patients with SCC of the anal canal treated with definitive CRT using HT IMRT from 2005 to 2017 were collected. Pre-treatment patient characteristics examined for correlations with PFS included: hemoglobin (Hgb) level, age, diabetes mellitus (DM) status, smoking status, neutropenia, thrombocytopenia, leukopenia, neutrophil/lymphocyte ratio, neutrophil/WBC ratio, lymphocyte/WBC ratio, sex, transplant status, HIV status, Karnofsky performance score, T-stage, and N-stage. Pre-treatment Hgb levels were recorded within two weeks prior to starting CRT. Clinical outcomes, including PFS, were described using the Kaplan-Meier estimator. A multivariable (MVA) Cox model of PFS evaluated the impact of pre-treatment Hgb and diabetes while adjusting for T-stage and age. Results: The median patient age was 57 years old (range, 26-87) and there were 39 females (63.9%) with the remaining patients identifying as males. Median patient follow up was 5.8 years. The PFS was 83% at 5 years. The median pre-treatment Hgb was 13 g/dL. On multivariable analysis (MVA), Hgb ≤10 g/dL (HR: 11.891, 95% CI: 2.649-53.391, P=0.001) and a diagnosis of diabetes mellitus (HR: 4.524, 95% CI: 1.436-14.252, P=0.010) were both significantly associated with a worse PFS. These factors were independent of T-stage and age. Conclusions: Long-term clinical outcomes for patients with SCC of the anal canal treated with definitive CRT are presented. Pre-treatment hemoglobin of ≤10 g/dL and diabetes were both independently associated with worse PFS on MVA. This retrospective data supports further prospective study of the impact of hematologic markers and medical co-morbidities such as DM and their management on clinical outcomes for patients with SCC of the anal canal treated with curative-intent CRT.

Saddle block anesthetic technique for benign outpatient anorectal surgery.

BACKGROUND: Current American Society of Colorectal Surgery Clinical Practice Guidelines for Ambulatory Anorectal Surgery endorse use of monitored anesthesia care, general anesthesia, or spinal anesthesia based on physician and patient preference. Although several studies support the use of monitored anesthesia care over general anesthesia, the literature regarding spinal anesthesia is limited and heterogenous due to small sample sizes and disparate spinal anesthesia techniques. Saddle block anesthesia is a form of spinal anesthesia that localizes to the lowermost sacral spinal segments allowing for preservation of lower extremity motor function and faster recovery. We accrued one of the largest reported cohort of anorectal procedures using saddle block anesthesia, as such, we sought to evaluate our institutional 12-year experience. METHODS: Patients who underwent a benign anorectal procedure at our outpatient surgery center between July 2008-2020 were retrospectively reviewed. Demographics, surgical factors, perioperative times, and adverse events were collected from the electronic medical records. Saddle block anesthesia was generally performed in the preoperative area using a spinal needle (25-27 gauge) and a single injection technique of a 1:1 ratio local anesthetic mixed with 10% dextrose solution. Between 2.5-5 mg of hyperbaric anesthetic was injected intrathecally in the sitting position and the patient remained upright for 3-10 minutes. This technique of saddle block anesthesia provides analgesia for approximately 1-3 hours. RESULTS: In the study, 859 saddle block anesthesia patients were identified, with a mean age of 44.6 years and American Society of Anesthesia score of 1.9; 609 (70.9%) were male. Surgical indications included lesion removal (27.1%), anal fistula (25.8%), hemorrhoidectomy (24.7%), pilonidal disease (6.3%), anal fissure (5.8%), and a combination of prior (10.2%). Prone jackknife positioning was used in 91.6% of procedures. Saddle block anesthesia most often was performed with bupivacaine (48.9%) or ropivacaine (41.7%). The median procedural saddle block anesthesia time was 11 minutes, surgery time was 17 minutes, anesthesia time was 42 minutes, and recovery time was 91 minutes. Patients spent a median of 3 hours and 53 minutes in the facility. Adverse events included urinary retention (1.9%), conversion to general anesthesia (1.8%), spinal headache (1.5%), hemodynamic instability (0.9%), and injection site reaction (0.3%). CONCLUSION: Demonstrated using the largest known cohort of anorectal patients with saddle block anesthesia, saddle block anesthesia provides an effective method of analgesia to avoid general anesthesia with a low rate of adverse events.