Pietro Tonino - Academia.edu (original) (raw)

Papers by Pietro Tonino

Acta bio-medica : Atenei Parmensis, 2016

Scapular dyskinesis in pitchers can potentially lead to impairments in the optimal performance of... more Scapular dyskinesis in pitchers can potentially lead to impairments in the optimal performance of muscles of the shoulder complex. The purpose of this prospective study was to evaluate whether the use of a scapula stabilizing t-shirt can decrease stress and discomfort in over-head baseball pitchers. Thirty-two semi-professional baseball pitchers were divided into 2 groups. Group A dressed the scapula stabilizing t-shirt during the weekly practice while group B (control group) continued to follow their training program without the t-shirt. All pitchers underwent a clinical examination at the beginning of the study (T0), 4 weeks (T1) and 8 weeks after (T2). Data collected showed a better clinical outcome at T1 which increased in T2 for pitchers in Group A, while in Group B athletes these positive results were not observed. This study underlines that scapula-stabilizing t-shirt can have positive effects on shoulder discomfort in over-head athletes.

Techniques in Orthopaedics, 1987

Anesthesiology, Feb 1, 1996

Surgically induced ischemia and reperfusion is frequently accompanied by local and remote organ i... more Surgically induced ischemia and reperfusion is frequently accompanied by local and remote organ injury. It was hypothesized that this procedure may produce injurious oxidants such as hydrogen peroxide (H2O2), which, if unscavenged, will generate the highly toxic hydroxyl radical (.OH). Accordingly, it was proposed that tourniquet-induced exsanguination for limb surgery may be a useful ischemia-reperfusion model to investigate the presence of oxidants, particularly H2O2. In ten patients undergoing knee surgery, catheters were placed in the femoral vein of the limb operated on for collection of local blood and in a vein of the arm for sampling of systemic blood. Tourniquet-induced limb exsanguination was induced for about 2 h. After tourniquet release (reperfusion), blood samples were collected during a 2-h period for measurement of H2O2, xanthine oxidase activity, xanthine, uric acid (UA), glutathione, and glutathione disulfide. At 30 s of reperfusion, H2O2 concentrations increased (approximately 90%) from 133 +/- 5 to 248 +/- 8 nmol.ml-1 (P < 0.05) in local blood samples, but no change was evident in systemic blood. However, in both local and systemic blood, xanthine oxidase activity increased approximately 90% (1.91 +/- 0.07 to 3.93 +/- 0.41 and 2.19 +/- 0.07 to 3.57 +/- 0.12 nmol UA.ml-1.min-1, respectively) as did glutathione concentrations (1.27 +/- 0.04 to 2.69 +/- 0.14 and 1.27 +/- 0.03 to 2.43 +/- 0.13 mumol.ml-1, respectively). At 5 min reperfusion, in local blood, H2O2 concentrations and xanthine oxidase activity peaked at 796 +/- 38 nmol.ml-1 (approximately 500%) and 11.69 +/- 1.46 nmol UA.ml-1.min-1 (approximately 520%), respectively. In local blood, xanthine and UA increased from 1.49 +/- 0.07 to 8.36 +/- 0.33 nmol.ml-1 and 2.69 +/- 0.16 to 3.90 +/- 0.18 mumol.ml-1, respectively, whereas glutathione and glutathione disulfide increased to 5.13 +/- 0.36 mumol.ml-1 and 0.514 +/- 0.092 nmol.ml-1, respectively. In systemic blood, xanthine oxidase activity peaked at 4.75 +/- 0.20 UA nmol.ml-1.min-1. At 10 min reperfusion, local blood glutathione and UA peaked at 7.08 +/- 0.46 mumol.ml-1 and 4.67 +/- 0.26 mumol.ml-1, respectively, while the other metabolites decreased significantly toward pretourniquet levels. From 20 to 120 min, most metabolites returned to pretourniquet levels; however, local and systemic blood xanthine oxidase activity remained increased 3.76 +/- 0.29 and 3.57 +/- 0.37 nmol UA.ml-1.min-1, respectively. Systemic blood H2O2 was never increased during the study. During the burst period (approximately 5-10 min), local blood H2O2 concentrations and xanthine oxidase activities were highly correlated (r = 0.999). These studies suggest that tourniquet-induced exsanguination for limb surgery is a significant source for toxic oxygen production in the form of H2O2 and that xanthine oxidase is probably the H2O2-generating enzyme that is formed during the ischemia-reperfusion event. In contrast to the reperfused leg, the absence of H2O2 in arm blood demonstrated a balanced oxidant scavenging in the systemic circulation, despite the persistent increase in systemic xanthine oxidase activity.

Arthroscopy and Sport Injuries, 2016

The Journal of bone and joint surgery. American volume, 2006

Subacromial corticosteroid injections are commonly used in the nonoperative management of rotator... more Subacromial corticosteroid injections are commonly used in the nonoperative management of rotator cuff disease. The effects of corticosteroid injection on injured rotator cuff tendons have not been studied. Our aims were to characterize the acute response of rotator cuff tendons to injury through the analysis of the type-III to type-I collagen expression ratio, a tendon injury marker, and to examine the effects of corticosteroid on this response. Sixty Sprague-Dawley rats were randomly assigned to four groups: control, tendon injury, steroid treatment, and tendon injury and steroid treatment. Six rats served as sham controls. Unilateral tendon injuries were created with full-thickness defects across 50% of the total width of the infraspinatus tendon, 5 mm from its humeral insertion. Steroid treatment with a single dose of methylprednisolone (0.6 mg/kg), equivalent to that given to humans, was injected into the subacromial space under direct visualization. Steroid treatment followed ...

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2015

To determine if the use of thigh-high compression stockings could decrease the incidence of cereb... more To determine if the use of thigh-high compression stockings could decrease the incidence of cerebral desaturation events (CDEs) in patients with a body mass index (BMI) of 30 kg/m(2) or greater undergoing shoulder arthroscopy in the beach-chair position (BCP). Between December 2013 and May 2014, 23 patients aged 18 years or older with a BMI of 30 kg/m(2) or greater undergoing shoulder arthroscopy in the BCP were monitored intraoperatively using near-infrared spectroscopy while wearing thigh-high compression stockings. Data obtained on these patients were compared with data from a previous cohort at our institution comprising 24 patients with a BMI of 30 kg/m(2) or greater who underwent elective shoulder arthroscopy in the BCP with the same monitoring but without wearing compression stockings. The incidence of CDEs was identified in each group. The incidence of CDEs in the group with compression stockings was 4% (1 of 23) compared with 18% (7 of 24) in the group without compression stockings (P = .048). There were no statistically significant differences in mean age (53.0 years v 53.3 years, P = .91), mean BMI (34.5 kg/m(2)v 36.2 kg/m(2), P = .21), or various medical comorbidities between the treatment group and control group. There was a significant difference in the operative time between the treatment group (156.6 minutes) and control group (94.1 minutes) (P < .001). The use of thigh-high compression stockings may decrease the incidence of CDEs in obese patients undergoing shoulder arthroscopy in the BCP. Level IV, therapeutic case series.

Orthopedics, 2007

Anterior cruciate ligament (ACL) reconstruction is a relatively common orthopedic procedure, with... more Anterior cruciate ligament (ACL) reconstruction is a relatively common orthopedic procedure, with patellar tendon frequently a graft source. However, controversy exists regarding the decision to use autograft or allograft patellar tendon tissue. This experimental study used computed tomography (CT) to compare the percentage of bone graft incorporation following ACL reconstruction using autografts and allografts. Fifty consecutive patients undergoing ACL reconstruction were included in the study. The tibial bone plug was imaged with CT 1 week, 2 months, and 5 months postoperatively. Four images from each completed scan were analyzed for percentage of incorporation of the bone graft. The results of autograft and allograft incorporation for each of the time intervals were compared. No statistically significant difference was found in the amount of bone incorporation at the tibial bone plug 1 week, 2 months, and 5 months. Clinical concerns regarding slower or less complete healing of al...

Orthopedics, 2013

Patellofemoral instability is related to anatomy. Magnetic resonance imaging (MRI) provides anato... more Patellofemoral instability is related to anatomy. Magnetic resonance imaging (MRI) provides anatomic detail, but spoiled gradient echo (SPGR) imaging during isometric quadriceps contraction provides objective functional data for diagnosing patellofemoral laxity. Knee MRI studies and medical charts of 398 patients were retrospectively reviewed. Two independent blinded observers evaluated the knee MRI studies for patellofemoral morphology and patellar position on axial SPGR images during relaxation and isometric quadriceps contraction for lateral patellar migration. Charts were reviewed for history of patellofemoral instability or dislocation. Patients were divided into 2 groups: group 1 comprised patients with 2.5 mm or more of lateral patellar migration on axial SPGR images, and group 2 comprised patients with less than 2.5 mm of patellar subluxation. Logistic regression models were used to determine relationships between patellofemoral subluxation of 2.5 mm or more and (1) history of dislocation or clinical patellofemoral instability, (2) grade 4 chondromalacia on MRI, (3) corrected central trochlear height, and (4) differential trochlear height (corrected for lateral condylar height). Statistically significant associations were found between patellar subluxation and each of the above 4 clinical/morphologic measures. Lateral patellar migration of 2.5 mm or more on SPGR obtained during quadriceps contraction had statistically significant associations with the above 4 measures. Evaluation of SPGR of quadriceps contraction provides objective functional information about patellofemoral instability for management decisions.

Journal of Surgical Orthopaedic Advances, 2014

The aim of this prospective cohort study was to investigate the effect of head and neck positioni... more The aim of this prospective cohort study was to investigate the effect of head and neck positioning on cerebral perfusion during shoulder arthroscopy in the beach chair position. Regional cerebral tissue oxygen saturation (rSO2) was monitored intraoperatively using near-infrared spectroscopy on 51 consecutive patients undergoing arthroscopic shoulder surgery in the beach chair position. The head of each subject was manipulated by the examiner and sequentially positioned for 45 seconds in terminal flexion, extension, bilateral rotation, and bilateral lateral bending. Decreases in rSO2 of 20% or greater from baseline were defined as a cerebral desaturation event (CDE). The association between head and neck position and cerebral perfusion was assessed. Eight percent of patients (4/51) experienced CDE during head and neck positioning. Body mass index was found to be a risk factor for CDE (p = .05). When comparing preoperative baseline rSO2 to intraoperative supine and intraoperative upright rSO2, there was no significant decrease in saturation levels for any of the six tested positions. Frequent intraoperative evaluations of the head and neck position as well as careful preoperative positioning may reduce the risk of position-related complications in patients undergoing elective shoulder arthroscopy in the beach chair position. In this study's patient population, however, head and neck position was not found to cause significant cerebral desaturation for the time period tested compared to preoperative baselines.

Techniques in Orthopaedics, 1987

Journal of Shoulder and Elbow Surgery, 2013

Journal of Shoulder and Elbow Surgery, 2013

Patients undergoing shoulder surgery in the beach chair position may be at increased risk for ser... more Patients undergoing shoulder surgery in the beach chair position may be at increased risk for serious neurocognitive complications due to cerebral ischemia. We sought to define the incidence, patient risk factors, and clinical sequelae of intraoperative cerebral desaturation events. Regional cerebral tissue oxygen saturation (rSO2) was monitored intra-operatively using near-infrared spectroscopy (NIRS) on 50 consecutive patients. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was administered to each patient pre- and postoperatively. Intra-operative decreases in rSO2 of 20% or greater were defined as cerebral desaturation events (CDE). The association between intraoperative CDE and postoperative cognitive decline was assessed. The incidence of intraoperative CDE in our series was 18% (9/50). Increased body mass index (BMI) was found to have a statistically significant association with intraoperative CDE (mean BMI 37.32 vs 28.59, P < .0001). There was no statistical significance in pre- vs postoperative RBANS either in composite scores or any of the sub-indices in either group. The degree and duration of cerebral ischemia required to produce neurocognitive dysfunction in this patient population remains undefined; however, cerebral oximetry with NIRS allows prompt identification and treatment of decreased cerebral perfusion decreasing the risk of this event. Increased BMI was found to be a statistically significant patient risk factor for the development of intra-operative CDE. The transient intra-operative CDEs were not associated with postoperative cognitive dysfunction in our patient series. We believe protocols aimed at detecting and reversing CDE minimize the risk of neurocognitive dysfunction and improve patient safety.

The Journal of Bone and Joint Surgery (American), 2006

Background: Subacromial corticosteroid injections are commonly used in the nonoperative managemen... more Background: Subacromial corticosteroid injections are commonly used in the nonoperative management of rotator cuff disease. The effects of corticosteroid injection on injured rotator cuff tendons have not been studied. Our aims were to characterize the acute response of rotator cuff tendons to injury through the analysis of the type-III to type-I collagen expression ratio, a tendon injury marker, and to examine the effects of corticosteroid on this response.

The Journal of Bone and Joint Surgery (American), 2009

Background: The effect of corticosteroids on tendon properties is poorly understood, and current ... more Background: The effect of corticosteroids on tendon properties is poorly understood, and current data are contradictory and diverse. The biomechanical effect of steroids on rotator cuff tendon has not been studied, to our knowledge. The current study was undertaken to characterize the biomechanical effects of corticosteroid exposure on both uninjured and injured rat rotator cuff tendon.

Clinical Orthopaedics and Related Research®, 2013

Patients undergoing arthroscopic shoulder surgery in the beach chair position may be at increased... more Patients undergoing arthroscopic shoulder surgery in the beach chair position may be at increased risk for serious neurocognitive complications as a result of cerebral ischemia. We sought to define the (1) incidence; (2) timing; and (3) magnitude of intraoperative cerebral desaturation events (CDEs) in subjects undergoing arthroscopic shoulder surgery in the beach chair position, as well as whether (4) the length of surgery was an independent risk factor for intraoperative CDEs. Regional cerebral tissue oxygen saturation (rSO2) was monitored intraoperatively using near-infrared spectroscopy on 51 consecutive patients undergoing arthroscopic shoulder surgery in the beach chair position. Intraoperative decreases in rSO2 of 20% or greater were defined as CDEs. The incidence of intraoperative CDEs in our series was 18% (nine of 51). Among the patients demonstrating CDE (n = 9), the mean time to onset of initial CDE was 18 minutes 38 seconds postinduction. Of those experiencing CDEs, the mean maximal decrease in rSO2 was 32% from preoperative baseline per patient. Additionally, the mean number of separate CDE instances was 1.89 in this patient population with an average duration of 3 minutes 3 seconds per instance. There was no statistically significant difference (p = 0.202) between patients demonstrating CDEs and those without in regard to length of surgery (95 versus 88 minutes). The degree and duration of cerebral ischemia required to produce neurocognitive dysfunction in this patient population remains undefined; however, cerebral oximetry with near-infrared spectroscopy allows prompt identification and treatment of decreased cerebral perfusion. We believe protocols aimed at detecting and reversing CDE may improve patient safety.

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2012

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2012

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2012

Anesthesiology, 1996

Surgically induced ischemia and reperfusion is frequently accompanied by local and remote organ i... more Surgically induced ischemia and reperfusion is frequently accompanied by local and remote organ injury. It was hypothesized that this procedure may produce injurious oxidants such as hydrogen peroxide (H2O2), which, if unscavenged, will generate the highly toxic hydroxyl radical (.OH). Accordingly, it was proposed that tourniquet-induced exsanguination for limb surgery may be a useful ischemia-reperfusion model to investigate the presence of oxidants, particularly H2O2. In ten patients undergoing knee surgery, catheters were placed in the femoral vein of the limb operated on for collection of local blood and in a vein of the arm for sampling of systemic blood. Tourniquet-induced limb exsanguination was induced for about 2 h. After tourniquet release (reperfusion), blood samples were collected during a 2-h period for measurement of H2O2, xanthine oxidase activity, xanthine, uric acid (UA), glutathione, and glutathione disulfide. At 30 s of reperfusion, H2O2 concentrations increased (approximately 90%) from 133 +/- 5 to 248 +/- 8 nmol.ml-1 (P < 0.05) in local blood samples, but no change was evident in systemic blood. However, in both local and systemic blood, xanthine oxidase activity increased approximately 90% (1.91 +/- 0.07 to 3.93 +/- 0.41 and 2.19 +/- 0.07 to 3.57 +/- 0.12 nmol UA.ml-1.min-1, respectively) as did glutathione concentrations (1.27 +/- 0.04 to 2.69 +/- 0.14 and 1.27 +/- 0.03 to 2.43 +/- 0.13 mumol.ml-1, respectively). At 5 min reperfusion, in local blood, H2O2 concentrations and xanthine oxidase activity peaked at 796 +/- 38 nmol.ml-1 (approximately 500%) and 11.69 +/- 1.46 nmol UA.ml-1.min-1 (approximately 520%), respectively. In local blood, xanthine and UA increased from 1.49 +/- 0.07 to 8.36 +/- 0.33 nmol.ml-1 and 2.69 +/- 0.16 to 3.90 +/- 0.18 mumol.ml-1, respectively, whereas glutathione and glutathione disulfide increased to 5.13 +/- 0.36 mumol.ml-1 and 0.514 +/- 0.092 nmol.ml-1, respectively. In systemic blood, xanthine oxidase activity peaked at 4.75 +/- 0.20 UA nmol.ml-1.min-1. At 10 min reperfusion, local blood glutathione and UA peaked at 7.08 +/- 0.46 mumol.ml-1 and 4.67 +/- 0.26 mumol.ml-1, respectively, while the other metabolites decreased significantly toward pretourniquet levels. From 20 to 120 min, most metabolites returned to pretourniquet levels; however, local and systemic blood xanthine oxidase activity remained increased 3.76 +/- 0.29 and 3.57 +/- 0.37 nmol UA.ml-1.min-1, respectively. Systemic blood H2O2 was never increased during the study. During the burst period (approximately 5-10 min), local blood H2O2 concentrations and xanthine oxidase activities were highly correlated (r = 0.999). These studies suggest that tourniquet-induced exsanguination for limb surgery is a significant source for toxic oxygen production in the form of H2O2 and that xanthine oxidase is probably the H2O2-generating enzyme that is formed during the ischemia-reperfusion event. In contrast to the reperfused leg, the absence of H2O2 in arm blood demonstrated a balanced oxidant scavenging in the systemic circulation, despite the persistent increase in systemic xanthine oxidase activity.

Anesthesia & Analgesia, 2000

Reports of transient neurological symptoms with the use of subarachnoid lidocaine has generated i... more Reports of transient neurological symptoms with the use of subarachnoid lidocaine has generated interest in alternate local anesthetics of intermediate duration, such as mepivacaine. This prospective randomized, double-blinded, dose-response study examined the anesthetic and recovery profiles of 60- and 80-mg doses of preservative-free plain mepivacaine for ambulatory spinal anesthesia. Sixty patients undergoing ambulatory anterior cruciate ligament repair of the knee under spinal anesthesia were randomized into two groups; Group 1 (29 patients) received 4 mL of 1.5% (60-mg dose) and Group 2 (31 patients) received 4 mL of 2% (80-mg dose) of plain mepivacaine. All patients received a combined spinal-epidural anesthetic technique. The epidural catheter was used only in the event the surgery outlasted the duration of surgical anesthesia with subarachnoid mepivacaine. Epidural supplementation was administered in three patients (12%) in Group 1 and one patient (3%) in Group 2 when the sensory block regressed to L-1 with surgery expected to last longer than 15 min. The cephalad dermatome level of the block and degree of motor block was comparable in the two groups. Times to two-segment and T-10 regression were comparable in the two groups (112 +/- 26 min in Group 1 versus 122 +/- 28 min in Group 2). Time to L-1 regression was significantly longer in Group 2 (146 +/- 28 min in Group 1 versus 159 +/- 19 min in Group 2). All of the ambulatory milestones were significantly faster in Group 1. Side effects, such as hypotension and emesis were negligible, severe bradycardia and urinary retention did not occur, and none of the patients in the two groups reported transient neurological symptoms over 24 h. In conclusion, plain mepivacaine in a 60- or 80-mg dose is a suitable local anesthetic choice for ambulatory spinal anesthesia with respect to anesthetic, as well as recovery profiles. We evaluated the anesthetic and recovery profiles of 60- and 80-mg doses of plain mepivacaine for ambulatory spinal anesthesia. Both doses produced comparable sensory and motor block. Sensory and motor regression and ambulatory milestones were 20-30 min longer with the 80-mg dose. Side effects were negligible and transient neurological symptoms were not reported during a 24-h follow-up.

Acta bio-medica : Atenei Parmensis, 2016

Scapular dyskinesis in pitchers can potentially lead to impairments in the optimal performance of... more Scapular dyskinesis in pitchers can potentially lead to impairments in the optimal performance of muscles of the shoulder complex. The purpose of this prospective study was to evaluate whether the use of a scapula stabilizing t-shirt can decrease stress and discomfort in over-head baseball pitchers. Thirty-two semi-professional baseball pitchers were divided into 2 groups. Group A dressed the scapula stabilizing t-shirt during the weekly practice while group B (control group) continued to follow their training program without the t-shirt. All pitchers underwent a clinical examination at the beginning of the study (T0), 4 weeks (T1) and 8 weeks after (T2). Data collected showed a better clinical outcome at T1 which increased in T2 for pitchers in Group A, while in Group B athletes these positive results were not observed. This study underlines that scapula-stabilizing t-shirt can have positive effects on shoulder discomfort in over-head athletes.

Techniques in Orthopaedics, 1987

Anesthesiology, Feb 1, 1996

Surgically induced ischemia and reperfusion is frequently accompanied by local and remote organ i... more Surgically induced ischemia and reperfusion is frequently accompanied by local and remote organ injury. It was hypothesized that this procedure may produce injurious oxidants such as hydrogen peroxide (H2O2), which, if unscavenged, will generate the highly toxic hydroxyl radical (.OH). Accordingly, it was proposed that tourniquet-induced exsanguination for limb surgery may be a useful ischemia-reperfusion model to investigate the presence of oxidants, particularly H2O2. In ten patients undergoing knee surgery, catheters were placed in the femoral vein of the limb operated on for collection of local blood and in a vein of the arm for sampling of systemic blood. Tourniquet-induced limb exsanguination was induced for about 2 h. After tourniquet release (reperfusion), blood samples were collected during a 2-h period for measurement of H2O2, xanthine oxidase activity, xanthine, uric acid (UA), glutathione, and glutathione disulfide. At 30 s of reperfusion, H2O2 concentrations increased (approximately 90%) from 133 +/- 5 to 248 +/- 8 nmol.ml-1 (P < 0.05) in local blood samples, but no change was evident in systemic blood. However, in both local and systemic blood, xanthine oxidase activity increased approximately 90% (1.91 +/- 0.07 to 3.93 +/- 0.41 and 2.19 +/- 0.07 to 3.57 +/- 0.12 nmol UA.ml-1.min-1, respectively) as did glutathione concentrations (1.27 +/- 0.04 to 2.69 +/- 0.14 and 1.27 +/- 0.03 to 2.43 +/- 0.13 mumol.ml-1, respectively). At 5 min reperfusion, in local blood, H2O2 concentrations and xanthine oxidase activity peaked at 796 +/- 38 nmol.ml-1 (approximately 500%) and 11.69 +/- 1.46 nmol UA.ml-1.min-1 (approximately 520%), respectively. In local blood, xanthine and UA increased from 1.49 +/- 0.07 to 8.36 +/- 0.33 nmol.ml-1 and 2.69 +/- 0.16 to 3.90 +/- 0.18 mumol.ml-1, respectively, whereas glutathione and glutathione disulfide increased to 5.13 +/- 0.36 mumol.ml-1 and 0.514 +/- 0.092 nmol.ml-1, respectively. In systemic blood, xanthine oxidase activity peaked at 4.75 +/- 0.20 UA nmol.ml-1.min-1. At 10 min reperfusion, local blood glutathione and UA peaked at 7.08 +/- 0.46 mumol.ml-1 and 4.67 +/- 0.26 mumol.ml-1, respectively, while the other metabolites decreased significantly toward pretourniquet levels. From 20 to 120 min, most metabolites returned to pretourniquet levels; however, local and systemic blood xanthine oxidase activity remained increased 3.76 +/- 0.29 and 3.57 +/- 0.37 nmol UA.ml-1.min-1, respectively. Systemic blood H2O2 was never increased during the study. During the burst period (approximately 5-10 min), local blood H2O2 concentrations and xanthine oxidase activities were highly correlated (r = 0.999). These studies suggest that tourniquet-induced exsanguination for limb surgery is a significant source for toxic oxygen production in the form of H2O2 and that xanthine oxidase is probably the H2O2-generating enzyme that is formed during the ischemia-reperfusion event. In contrast to the reperfused leg, the absence of H2O2 in arm blood demonstrated a balanced oxidant scavenging in the systemic circulation, despite the persistent increase in systemic xanthine oxidase activity.

Arthroscopy and Sport Injuries, 2016

The Journal of bone and joint surgery. American volume, 2006

Subacromial corticosteroid injections are commonly used in the nonoperative management of rotator... more Subacromial corticosteroid injections are commonly used in the nonoperative management of rotator cuff disease. The effects of corticosteroid injection on injured rotator cuff tendons have not been studied. Our aims were to characterize the acute response of rotator cuff tendons to injury through the analysis of the type-III to type-I collagen expression ratio, a tendon injury marker, and to examine the effects of corticosteroid on this response. Sixty Sprague-Dawley rats were randomly assigned to four groups: control, tendon injury, steroid treatment, and tendon injury and steroid treatment. Six rats served as sham controls. Unilateral tendon injuries were created with full-thickness defects across 50% of the total width of the infraspinatus tendon, 5 mm from its humeral insertion. Steroid treatment with a single dose of methylprednisolone (0.6 mg/kg), equivalent to that given to humans, was injected into the subacromial space under direct visualization. Steroid treatment followed ...

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2015

To determine if the use of thigh-high compression stockings could decrease the incidence of cereb... more To determine if the use of thigh-high compression stockings could decrease the incidence of cerebral desaturation events (CDEs) in patients with a body mass index (BMI) of 30 kg/m(2) or greater undergoing shoulder arthroscopy in the beach-chair position (BCP). Between December 2013 and May 2014, 23 patients aged 18 years or older with a BMI of 30 kg/m(2) or greater undergoing shoulder arthroscopy in the BCP were monitored intraoperatively using near-infrared spectroscopy while wearing thigh-high compression stockings. Data obtained on these patients were compared with data from a previous cohort at our institution comprising 24 patients with a BMI of 30 kg/m(2) or greater who underwent elective shoulder arthroscopy in the BCP with the same monitoring but without wearing compression stockings. The incidence of CDEs was identified in each group. The incidence of CDEs in the group with compression stockings was 4% (1 of 23) compared with 18% (7 of 24) in the group without compression stockings (P = .048). There were no statistically significant differences in mean age (53.0 years v 53.3 years, P = .91), mean BMI (34.5 kg/m(2)v 36.2 kg/m(2), P = .21), or various medical comorbidities between the treatment group and control group. There was a significant difference in the operative time between the treatment group (156.6 minutes) and control group (94.1 minutes) (P < .001). The use of thigh-high compression stockings may decrease the incidence of CDEs in obese patients undergoing shoulder arthroscopy in the BCP. Level IV, therapeutic case series.

Orthopedics, 2007

Anterior cruciate ligament (ACL) reconstruction is a relatively common orthopedic procedure, with... more Anterior cruciate ligament (ACL) reconstruction is a relatively common orthopedic procedure, with patellar tendon frequently a graft source. However, controversy exists regarding the decision to use autograft or allograft patellar tendon tissue. This experimental study used computed tomography (CT) to compare the percentage of bone graft incorporation following ACL reconstruction using autografts and allografts. Fifty consecutive patients undergoing ACL reconstruction were included in the study. The tibial bone plug was imaged with CT 1 week, 2 months, and 5 months postoperatively. Four images from each completed scan were analyzed for percentage of incorporation of the bone graft. The results of autograft and allograft incorporation for each of the time intervals were compared. No statistically significant difference was found in the amount of bone incorporation at the tibial bone plug 1 week, 2 months, and 5 months. Clinical concerns regarding slower or less complete healing of al...

Orthopedics, 2013

Patellofemoral instability is related to anatomy. Magnetic resonance imaging (MRI) provides anato... more Patellofemoral instability is related to anatomy. Magnetic resonance imaging (MRI) provides anatomic detail, but spoiled gradient echo (SPGR) imaging during isometric quadriceps contraction provides objective functional data for diagnosing patellofemoral laxity. Knee MRI studies and medical charts of 398 patients were retrospectively reviewed. Two independent blinded observers evaluated the knee MRI studies for patellofemoral morphology and patellar position on axial SPGR images during relaxation and isometric quadriceps contraction for lateral patellar migration. Charts were reviewed for history of patellofemoral instability or dislocation. Patients were divided into 2 groups: group 1 comprised patients with 2.5 mm or more of lateral patellar migration on axial SPGR images, and group 2 comprised patients with less than 2.5 mm of patellar subluxation. Logistic regression models were used to determine relationships between patellofemoral subluxation of 2.5 mm or more and (1) history of dislocation or clinical patellofemoral instability, (2) grade 4 chondromalacia on MRI, (3) corrected central trochlear height, and (4) differential trochlear height (corrected for lateral condylar height). Statistically significant associations were found between patellar subluxation and each of the above 4 clinical/morphologic measures. Lateral patellar migration of 2.5 mm or more on SPGR obtained during quadriceps contraction had statistically significant associations with the above 4 measures. Evaluation of SPGR of quadriceps contraction provides objective functional information about patellofemoral instability for management decisions.

Journal of Surgical Orthopaedic Advances, 2014

The aim of this prospective cohort study was to investigate the effect of head and neck positioni... more The aim of this prospective cohort study was to investigate the effect of head and neck positioning on cerebral perfusion during shoulder arthroscopy in the beach chair position. Regional cerebral tissue oxygen saturation (rSO2) was monitored intraoperatively using near-infrared spectroscopy on 51 consecutive patients undergoing arthroscopic shoulder surgery in the beach chair position. The head of each subject was manipulated by the examiner and sequentially positioned for 45 seconds in terminal flexion, extension, bilateral rotation, and bilateral lateral bending. Decreases in rSO2 of 20% or greater from baseline were defined as a cerebral desaturation event (CDE). The association between head and neck position and cerebral perfusion was assessed. Eight percent of patients (4/51) experienced CDE during head and neck positioning. Body mass index was found to be a risk factor for CDE (p = .05). When comparing preoperative baseline rSO2 to intraoperative supine and intraoperative upright rSO2, there was no significant decrease in saturation levels for any of the six tested positions. Frequent intraoperative evaluations of the head and neck position as well as careful preoperative positioning may reduce the risk of position-related complications in patients undergoing elective shoulder arthroscopy in the beach chair position. In this study's patient population, however, head and neck position was not found to cause significant cerebral desaturation for the time period tested compared to preoperative baselines.

Techniques in Orthopaedics, 1987

Journal of Shoulder and Elbow Surgery, 2013

Journal of Shoulder and Elbow Surgery, 2013

Patients undergoing shoulder surgery in the beach chair position may be at increased risk for ser... more Patients undergoing shoulder surgery in the beach chair position may be at increased risk for serious neurocognitive complications due to cerebral ischemia. We sought to define the incidence, patient risk factors, and clinical sequelae of intraoperative cerebral desaturation events. Regional cerebral tissue oxygen saturation (rSO2) was monitored intra-operatively using near-infrared spectroscopy (NIRS) on 50 consecutive patients. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was administered to each patient pre- and postoperatively. Intra-operative decreases in rSO2 of 20% or greater were defined as cerebral desaturation events (CDE). The association between intraoperative CDE and postoperative cognitive decline was assessed. The incidence of intraoperative CDE in our series was 18% (9/50). Increased body mass index (BMI) was found to have a statistically significant association with intraoperative CDE (mean BMI 37.32 vs 28.59, P < .0001). There was no statistical significance in pre- vs postoperative RBANS either in composite scores or any of the sub-indices in either group. The degree and duration of cerebral ischemia required to produce neurocognitive dysfunction in this patient population remains undefined; however, cerebral oximetry with NIRS allows prompt identification and treatment of decreased cerebral perfusion decreasing the risk of this event. Increased BMI was found to be a statistically significant patient risk factor for the development of intra-operative CDE. The transient intra-operative CDEs were not associated with postoperative cognitive dysfunction in our patient series. We believe protocols aimed at detecting and reversing CDE minimize the risk of neurocognitive dysfunction and improve patient safety.

The Journal of Bone and Joint Surgery (American), 2006

Background: Subacromial corticosteroid injections are commonly used in the nonoperative managemen... more Background: Subacromial corticosteroid injections are commonly used in the nonoperative management of rotator cuff disease. The effects of corticosteroid injection on injured rotator cuff tendons have not been studied. Our aims were to characterize the acute response of rotator cuff tendons to injury through the analysis of the type-III to type-I collagen expression ratio, a tendon injury marker, and to examine the effects of corticosteroid on this response.

The Journal of Bone and Joint Surgery (American), 2009

Background: The effect of corticosteroids on tendon properties is poorly understood, and current ... more Background: The effect of corticosteroids on tendon properties is poorly understood, and current data are contradictory and diverse. The biomechanical effect of steroids on rotator cuff tendon has not been studied, to our knowledge. The current study was undertaken to characterize the biomechanical effects of corticosteroid exposure on both uninjured and injured rat rotator cuff tendon.

Clinical Orthopaedics and Related Research®, 2013

Patients undergoing arthroscopic shoulder surgery in the beach chair position may be at increased... more Patients undergoing arthroscopic shoulder surgery in the beach chair position may be at increased risk for serious neurocognitive complications as a result of cerebral ischemia. We sought to define the (1) incidence; (2) timing; and (3) magnitude of intraoperative cerebral desaturation events (CDEs) in subjects undergoing arthroscopic shoulder surgery in the beach chair position, as well as whether (4) the length of surgery was an independent risk factor for intraoperative CDEs. Regional cerebral tissue oxygen saturation (rSO2) was monitored intraoperatively using near-infrared spectroscopy on 51 consecutive patients undergoing arthroscopic shoulder surgery in the beach chair position. Intraoperative decreases in rSO2 of 20% or greater were defined as CDEs. The incidence of intraoperative CDEs in our series was 18% (nine of 51). Among the patients demonstrating CDE (n = 9), the mean time to onset of initial CDE was 18 minutes 38 seconds postinduction. Of those experiencing CDEs, the mean maximal decrease in rSO2 was 32% from preoperative baseline per patient. Additionally, the mean number of separate CDE instances was 1.89 in this patient population with an average duration of 3 minutes 3 seconds per instance. There was no statistically significant difference (p = 0.202) between patients demonstrating CDEs and those without in regard to length of surgery (95 versus 88 minutes). The degree and duration of cerebral ischemia required to produce neurocognitive dysfunction in this patient population remains undefined; however, cerebral oximetry with near-infrared spectroscopy allows prompt identification and treatment of decreased cerebral perfusion. We believe protocols aimed at detecting and reversing CDE may improve patient safety.

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2012

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2012

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2012

Anesthesiology, 1996

Surgically induced ischemia and reperfusion is frequently accompanied by local and remote organ i... more Surgically induced ischemia and reperfusion is frequently accompanied by local and remote organ injury. It was hypothesized that this procedure may produce injurious oxidants such as hydrogen peroxide (H2O2), which, if unscavenged, will generate the highly toxic hydroxyl radical (.OH). Accordingly, it was proposed that tourniquet-induced exsanguination for limb surgery may be a useful ischemia-reperfusion model to investigate the presence of oxidants, particularly H2O2. In ten patients undergoing knee surgery, catheters were placed in the femoral vein of the limb operated on for collection of local blood and in a vein of the arm for sampling of systemic blood. Tourniquet-induced limb exsanguination was induced for about 2 h. After tourniquet release (reperfusion), blood samples were collected during a 2-h period for measurement of H2O2, xanthine oxidase activity, xanthine, uric acid (UA), glutathione, and glutathione disulfide. At 30 s of reperfusion, H2O2 concentrations increased (approximately 90%) from 133 +/- 5 to 248 +/- 8 nmol.ml-1 (P < 0.05) in local blood samples, but no change was evident in systemic blood. However, in both local and systemic blood, xanthine oxidase activity increased approximately 90% (1.91 +/- 0.07 to 3.93 +/- 0.41 and 2.19 +/- 0.07 to 3.57 +/- 0.12 nmol UA.ml-1.min-1, respectively) as did glutathione concentrations (1.27 +/- 0.04 to 2.69 +/- 0.14 and 1.27 +/- 0.03 to 2.43 +/- 0.13 mumol.ml-1, respectively). At 5 min reperfusion, in local blood, H2O2 concentrations and xanthine oxidase activity peaked at 796 +/- 38 nmol.ml-1 (approximately 500%) and 11.69 +/- 1.46 nmol UA.ml-1.min-1 (approximately 520%), respectively. In local blood, xanthine and UA increased from 1.49 +/- 0.07 to 8.36 +/- 0.33 nmol.ml-1 and 2.69 +/- 0.16 to 3.90 +/- 0.18 mumol.ml-1, respectively, whereas glutathione and glutathione disulfide increased to 5.13 +/- 0.36 mumol.ml-1 and 0.514 +/- 0.092 nmol.ml-1, respectively. In systemic blood, xanthine oxidase activity peaked at 4.75 +/- 0.20 UA nmol.ml-1.min-1. At 10 min reperfusion, local blood glutathione and UA peaked at 7.08 +/- 0.46 mumol.ml-1 and 4.67 +/- 0.26 mumol.ml-1, respectively, while the other metabolites decreased significantly toward pretourniquet levels. From 20 to 120 min, most metabolites returned to pretourniquet levels; however, local and systemic blood xanthine oxidase activity remained increased 3.76 +/- 0.29 and 3.57 +/- 0.37 nmol UA.ml-1.min-1, respectively. Systemic blood H2O2 was never increased during the study. During the burst period (approximately 5-10 min), local blood H2O2 concentrations and xanthine oxidase activities were highly correlated (r = 0.999). These studies suggest that tourniquet-induced exsanguination for limb surgery is a significant source for toxic oxygen production in the form of H2O2 and that xanthine oxidase is probably the H2O2-generating enzyme that is formed during the ischemia-reperfusion event. In contrast to the reperfused leg, the absence of H2O2 in arm blood demonstrated a balanced oxidant scavenging in the systemic circulation, despite the persistent increase in systemic xanthine oxidase activity.

Anesthesia & Analgesia, 2000

Reports of transient neurological symptoms with the use of subarachnoid lidocaine has generated i... more Reports of transient neurological symptoms with the use of subarachnoid lidocaine has generated interest in alternate local anesthetics of intermediate duration, such as mepivacaine. This prospective randomized, double-blinded, dose-response study examined the anesthetic and recovery profiles of 60- and 80-mg doses of preservative-free plain mepivacaine for ambulatory spinal anesthesia. Sixty patients undergoing ambulatory anterior cruciate ligament repair of the knee under spinal anesthesia were randomized into two groups; Group 1 (29 patients) received 4 mL of 1.5% (60-mg dose) and Group 2 (31 patients) received 4 mL of 2% (80-mg dose) of plain mepivacaine. All patients received a combined spinal-epidural anesthetic technique. The epidural catheter was used only in the event the surgery outlasted the duration of surgical anesthesia with subarachnoid mepivacaine. Epidural supplementation was administered in three patients (12%) in Group 1 and one patient (3%) in Group 2 when the sensory block regressed to L-1 with surgery expected to last longer than 15 min. The cephalad dermatome level of the block and degree of motor block was comparable in the two groups. Times to two-segment and T-10 regression were comparable in the two groups (112 +/- 26 min in Group 1 versus 122 +/- 28 min in Group 2). Time to L-1 regression was significantly longer in Group 2 (146 +/- 28 min in Group 1 versus 159 +/- 19 min in Group 2). All of the ambulatory milestones were significantly faster in Group 1. Side effects, such as hypotension and emesis were negligible, severe bradycardia and urinary retention did not occur, and none of the patients in the two groups reported transient neurological symptoms over 24 h. In conclusion, plain mepivacaine in a 60- or 80-mg dose is a suitable local anesthetic choice for ambulatory spinal anesthesia with respect to anesthetic, as well as recovery profiles. We evaluated the anesthetic and recovery profiles of 60- and 80-mg doses of plain mepivacaine for ambulatory spinal anesthesia. Both doses produced comparable sensory and motor block. Sensory and motor regression and ambulatory milestones were 20-30 min longer with the 80-mg dose. Side effects were negligible and transient neurological symptoms were not reported during a 24-h follow-up.