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Biomedical subjects

G S Fanton

Publications and source records attributed to G S Fanton.

At least 19 recordsLinked to original sources
PubMed2001

Monopolar radiofrequency energy for arthroscopic treatment of shoulder instability in the athlete.

Monopolar radiofrequency energy is increasingly being used in the treatment of shoulder instability. Basic science studies and early clinical results have shown that application of thermal energy can result in successful shrinkage of the shoulder capsule. This procedure is useful in treating certain traumatic and recurrent instability conditions of the shoulder especially in the athlete where range of motion is preserved, recovery is faster than with open procedures, and there, is little disruption or alteration of inherent anatomy. The procedure is technically easy to perform, and the complication rate is low. Success, however, depends on proper patient selection, attention to the rehabilitation program, and patient compliance. Long-term follow-up will be necessary to determine if results for this procedure will deteriorate over time, especially in patients with multidirectional instability.

Arthroscopy↗
PubMed2001

Two-year outcome of arthroscopic bankart repair and electrothermal-assisted capsulorrhaphy for recurrent traumatic anterior shoulder instability.

PURPOSE: Arthroscopic treatment of chronic anterior shoulder instability in active athletes is reportedly less successful than open techniques. We performed arthroscopic stabilization for confirmed capsulolabral avulsions and followed-up patients prospectively for a minimum of 24 months. TYPE OF STUDY: Prospective nonrandomized study. METHODS: We studied 42 patients (mean age, 26 years) with recurrent traumatic anterior dislocations. They reported an average of 9 dislocations preoperatively. An average of 69 months elapsed from initial dislocation to surgery. The shoulders underwent arthroscopic capsulolabral repair with either a suture anchor and horizontal mattress suture, or an absorbable tack. Each shoulder also was treated with a monopolar radiofrequency probe for thermal shrinkage of the middle, anteroinferior, and posteroinferior glenohumeral ligaments. Patients were evaluated prospectively for pain, motion, stability, and function using the modified Rowe score. RESULTS: At a mean of 28 months postoperatively, 38 patients had returned to their preinjury sports. Three patients (7%) had a traumatic redislocation. Using the modified Rowe score, statistically significant improvements were noted for pain, stability, and function. There was no significant change in motion. The overall modified Rowe score improved from 38 points preoperatively to 89 points at final evaluation (P <.001). CONCLUSIONS: These results indicate that arthroscopic treatment of patients with recurrent traumatic anterior instability yields results comparable to open procedures, including athletes involved in high-level contact and collision sports. We believe that addressing capsular laxity surgically is critical, particularly when dealing with chronic instability. This procedure allows the surgeon to reliably correct the labral detachment and the capsular redundancy while preserving motion and minimizing morbidity.

Adolescent↗
PubMed2000

The mechanism of joint capsule thermal modification in an in-vitro sheep model.

The purpose of this study was to understand the mechanism responsible for joint capsule shrinkage after nonablative laser application in an in-vitro sheep model. Femoropatellar joint capsular tissue specimens harvested from 20 adult sheep were treated with one of three power settings of a holmium:yttrium-aluminum-garnet laser or served as a control. Laser treatment significantly shortened the tissue and decreased tissue stiffness in all three laser groups, whereas failure strength was not altered significantly by laser treatment. Transmission electron microscopic examination showed swollen collagen fibrils and loss of membrane integrity of fibroblasts. A thermometric study revealed nonablative laser energy caused tissue temperature to rise in the range of 64 degrees C to 100 degrees C. Electrophoresis after trypsin digestion of the tissue revealed significant loss of distinct alpha bands of Type I collagen in laser treated samples, whereas alpha bands were present in laser treated tissue without trypsin digestion. The results of this study support the concept that the primary mechanism responsible for the effect of nonablative laser energy is thermal denaturation of collagen in joint capsular tissue associated with unwinding of the triple helical structure of the collagen molecule.

Analysis of Variance↗
PubMed2000

The biologic response to laser thermal modification in an in vivo sheep model.

The purpose of this study was to evaluate the effect of nonablative laser energy on mechanical, histologic, ultrastructural, and biochemical properties of joint capsular tissue in an in vivo sheep model. Femoropatellar joint capsule was treated with the holmium:yttrium-aluminum-garnet laser via an arthroscope, and tissues were harvested immediately after surgery, or at 3, 7, 14, 30, 60, 90, and 180 days after surgery (n = 8/group). Laser treatment caused significant decreases in tissue stiffness from 0 to 7 days after surgery, then stiffness gradually increased after 14 days. Tissue strength was lowest 3 days after laser treatment. Histologic examination revealed immediate collagen hyalinization and cell necrosis, followed by active cellular response characterized by extensive fibroblast migration and capillary sprouting. Tissue appeared to be normal histologically 60 days after surgery; however, collagen fibrils remained uniformly small. This study showed an active tissue response secondary to thermal modification with concomitant recovery of mechanical properties by 30 days after surgery. Whether the shrinkage or joint stability was maintained with time remains to be evaluated. To clarify the advantages and disadvantages of this technique, a carefully controlled clinical trial with long term followup should be performed.

Animals↗
PubMed2000

Effects of monopolar radiofrequency energy on ovine joint capsular mechanical properties.

Radiofrequency energy may provide a relatively noninvasive method to stabilize joints with excessive laxity by thermally shrinking redundant joint capsular tissue. The authors determined the percentage of shrinkage associated with five radiofrequency treatment temperatures and evaluated the effect of this energy on the structural properties of joint capsular tissue in vitro. First, 36 adult sheep femoropatellar joint capsular specimens were treated with one of five treatment temperatures (n = 6 per group) or served as a control to determine tissue shrinkage. An additional 24 specimens were treated with three temperatures that resulted in different shrinkage: 45 degrees C, 65 degrees C, and 85 degrees C. Tissue stiffness, relaxation, and failure strength were determined for each specimen (n = 6 per group). Tissue shrinkage was correlated significantly with treatment temperature. There was a significant decrease in tensile stiffness in the 65 degrees C and 85 degrees C treatment groups. There were no significant differences between stress relaxation before treatment and after treatment. Relaxation properties after treatment were not different from each other or from control values either normalized to pretreatment values or expressed as raw data. Failure strength was not affected significantly at any temperature.

Animals↗
PubMed2000

Comparative effects of laser and radiofrequency energy on joint capsule.

The study compared the effects of laser and monopolar radiofrequency energy on thermal and architectural properties of joint capsular tissue in an in vitro ovine model. Sheep glenohumeral joint capsular specimens were treated with laser (5, 10, 15 W) or radiofrequency energy (55 degrees, 65 degrees, 75 degrees C) (n = six per group). Energy application caused significant tissue shrinkage and decreased surface area in all laser and radiofrequency treatment groups. Tissue thickness significantly increased in all treatment groups except for radiofrequency 55 degrees C. Tissue shrinkage, surface area, and thickness each correlated significantly with the delivered laser energy per tissue area or mean radiofrequency probe temperature. There were no significant differences among laser 10 W, laser 15 W, and radiofrequency 75 degrees C treatment groups for these three architectural parameters. Tissue temperature was elevated significantly in the laser 10 W, laser 15 W, radiofrequency 65 degrees C, and radiofrequency 75 degrees C groups when compared with the control. Tissue temperature changes between the laser 10 W and radiofrequency 75 degrees C groups were similar; however, laser treatment produced a steeper temperature increase accompanying its peak temperature. Despite different mechanisms, laser and radiofrequency energy can achieve similar and predictable tissue modification, which is temperature dependent. Additional in vivo studies must be performed to evaluate the applicability of these techniques to clinical use.

Animals↗
PubMed1999

Arthroscopic treatment of shoulder instability: current concepts and techniques.

The incidence of glenohumeral joint instability is estimated to effect between 2 and 8% of the population. It represents at least one third of all shoulder related emergency room visits. When one considers the spectrum of shoulder instability, including transient subluxation, the true incidence of glenohumeral instability is probably grossly under-reported. Although any age group can be affected, shoulder instability is primarily a disease of the young. The occurrence of instability is inversely proportional to the age of the patient and the time of original injury. A patient who dislocates for the first time as a teen can expect a redislocation rate approaching 90% in his or her lifetime. Therefore, many authors recommend early surgical treatment to repair the lesion.

Journal Article↗
PubMed1996

[Shoulder arthroscopy using the holmium-YAG laser method. State of the art 1994].

The Ho:YAG laser has been found to be a safe and efficacious adjunct to many arthroscopic shoulder procedures. The curved, thin handpieces are easily manipulated around the surfaces of the joint. Postoperative inflammation is minimized, and a versatile instrument that can cut, coagulate, ablate, and cauterize has obvious benefit where optimal visualization is required. The potential for chondral contouring and bone resection is currently being studied, and the use of laser-induced thermal contraction of soft tissue collagen may add some exciting possibilities to the treatment of joint instabilities.

Arthroscopy↗
PubMed1996

[Arthroscopic management of recurrent anterior shoulder dislocation by combining a labrum suture with antero-inferior holmium:YAG laser capsular shrinkage].

Current arthroscopic treatments do not address satisfactorily the capsular redundancy frequently associated with the Bankart lesion in recurrent anterior dislocation. Although the Bankart lesion heals, many of the recurrences after arthroscopic procedures are due to capsular redundancy and the laxity of glenohumeral ligaments. We propose that laser-assisted capsular shrinkage (LACS) be combined with arthroscopic labrum reattachment. As shown by Market et al., significant capsular shrinkage can be achieved by the application of non-ablative Ho:YAG laser energy without detrimental effects to the relaxation properties of the tissue. For 1 year we have used LACS together with labrum suture in 18 shoulders in 18 patients (mean age 24.6 years). All patients suffered from chronic anterioinferior recurrent dislocation. The labrum suture was realized by an anterior reattachment (REVO screws, Linvatec, USA) or by transglenoid suture. Two or three sutures were passed through the torn labrum with 2/0 non-absorbable suture material. The LACS procedure was performed with a holmium:YAG laser (VersaPulse, Coherent, USA) at an energy of 10 W (1 J, 10 Hz) with a 30 degrees curved handpiece. All patients were immobilized in a sling for 4 weeks postoperatively. Physical therapy was begun at 1 month with passive and active exercise. To date, none of the patients have had a recurrence. Seven of 18 patients returned to their previous sports activity, and at the same level. None of the patients had an iatrogenic lesion due to the laser application or labrum suture. Compared to the other shoulder, the loss of external rotation with the arm 90 degrees abducted was 30 degrees at 4 weeks and 10 degrees at 4 months. We think that the LACS procedure is a good treatment for the capsular redundancy that is frequently associated with Bankart's lesion in recurrent anterior dislocation and is probably responsible for the high failure rate in current arthroscopic procedures. Our results are short-term results, but we expect the capsular shrinkage associated with the labrum reattachment will provide a long-term success rate that is comparable to open procedures.

Adult↗
PubMed1995

Patellar tendon graft harvesting using horizontal incisions for anterior cruciate ligament reconstruction.

Autograft endoscopic anterior cruciate ligament (ACL) reconstruction traditionally has been performed via standard arthroscopy portals and a single longitudinal anterior incision. This vertical incision is used for harvesting the central third of the patellar tendon with patellar and tibial bone blocks. From 1992 to 1995, more than 400 cases have been done with a new technique of graft procurement. This new method employs two transverse incisions that are more cosmetic and are less likely to become a source of pain or flexion limitation.

Anterior Cruciate Ligament↗
PubMed1995

Lateral retinacular release. The holmium:YAG laser versus electrocautery.

A retrospective study was conducted in which several parameters of postoperative recovery were compared between 2 groups of patients: 25 patients who had lateral retinacular release surgery in which the holmium:yttrium-aluminum-garnet (Ho:YAG) laser was used, and a control group of 17 patients who had the same surgery in which electrocautery was used. Postoperative recovery times of patients treated with the Ho:YAG laser were significantly decreased as compared with the recovery rates of patients in the control group. Morbidity also was reduced in the group for whom the laser was used. The results of this study indicate that the 2.1-micron-wave-length, pulsed Ho:YAG laser can be used safely and effectively to perform lateral retinacular release surgery.

Adult↗
PubMed1993

Intraarticular hemangioma of the knee.

Intraarticular hemangioma is a rare cause of knee pain and effusion. The presentation of unexplained recurrent hemearthrosis associated with no or minimal trauma, skin manifestations of hemangioma, and radiographic and magnetic resonance imaging study results should alert the clinician of this unusual entity. Successful arthroscopic ablation is reported with the use of the holmium:yttrium-aluminum-garnet (YAG) laser.

Adolescent↗
PubMed1993

Holmium laser surgery.

This relatively new form of laser energy, with its powerful and precise ability to ablate the dense tissues of the musculoskeletal system as well as its transmissibility in fiberoptic cables and a fluid medium, makes this an ideal tool for use in orthopedic surgery. Its importance as a new orthopedic modality may well lie in its unique ability to gain access to small articular compartments while providing superior homeostatic control, thereby decreasing postoperative morbidity. While not yet in widespread use, its popularity is rapidly spreading and research into a variety of new applications is growing steadily.

Arthroscopy↗
PubMed1988

The pseudoradicular syndrome. Lower extremity peripheral nerve entrapment masquerading as lumbar radiculopathy.

Of approximately 4,000 patients with complaints of lower extremity pain who were referred to our center for evaluation of suspected lumbar radiculopathy, 36 were found to have peripheral nerve entrapments as the sole cause of their leg pain. Nine patients had femoral nerve entrapments just proximal to the inguinal ligament. Seven patients had saphenous nerve entrapments about the knee. Twenty patients had peroneal nerve entrapments at or above the popliteal space. Nine patients had tibial nerve entrapments in the popliteal space. The diagnosis was established on the basis of electrophysiologic studies coupled with the results of selective spinal and peripheral nerve blocks. Seven patients with saphenous nerve lesions, 12 patients with peroneal nerve lesions, nine patients with tibial nerve lesions, and four patients with femoral nerve lesions, for a total of 32 (71%) cases underwent surgical exploration and external neurolysis. Forty-four percent of the cases had a positive nerve root tension sign, and 44% (20/45) had spinal range of motion abnormalities. Back pain complaints were noted in 49% (22/45) of the cases. The pseudoradicular syndrome should be considered in cases of undiagnosed persistent leg pain. Peripheral nerve lesions should be ruled out prior to considering lumbar spine surgery.

Adult↗
PubMedDate not supplied

The effect of radiofrequency energy on the length and temperature properties of the glenohumeral joint capsule.

The purpose of this in vitro study was to evaluate the effect of radiofrequency energy on the length and temperature properties of the glenohumeral joint capsule in a sheep model. Dissected glenohumeral joint capsules were placed in a 37 degrees C tissue bath and treated with radiofrequency energy at temperature settings of 60 degrees, 65 degrees, 70 degrees, 75 degrees and 80 degrees C. Pretreatment and posttreatment tissue length was measured, and tissue temperature changes were recorded at distances of 0.0, 0.5, 1.0, 1.5 mm away from the probe path. Tissue shrinkage was found to be less than 4% for treatments below 65 degrees C, and increased to 14% for treatments at 80 degrees C. Posttreatment lengths of tissues treated at 65 degrees, 70 degrees, 75 degrees, 80 degrees C were significantly shorter than pretreatment lengths. The maximum tissue temperatures directly below the probe were observed to be 3.7 degrees to 6.7 degrees C lower than the set temperatures. As the distance from the probe was increased, the tissue temperature was found to decrease, reaching a value of less than 45 degrees C at 1.5 mm for all five treatment temperature settings. This study provided basic information on temperature settings, tissue shrinkage, and tissue temperature distribution of radiofrequency treatment.

Animals↗
PubMedDate not supplied

The effect of radiofrequency energy on the ultrastructure of joint capsular collagen.

This study evaluated the effect of radiofrequency energy on the histological and ultrastructural appearance of joint capsular collagen. Femoropatellar joint capsular specimens from adult sheep were treated with one of three treatment temperatures (45 degrees C, 65 degrees C, and 85 degrees C) with a radiofrequency generator or served as control in a randomized block design. Twenty-four specimens (n = 6) were processed for histological examination as well as ultrastructural analysis using transmission electron microscopy. A computer-based area determination program was used to calculate the area affected in histological samples. Histological changes consisted of thermal tissue damage characterized by collagen fiber fusion and fibroblastic nuclear pyknosis at all application temperatures with clear demarcations between treated and untreated tissue. Mean tissue affected ranged from 50.4% for 85 degrees C to 22.5% for 45 degrees C. There was a strong correlation between treatment temperature and percent area affected (P < .001, R2 = .65). Ultrastructural alterations included a general increase in cross-sectional fibril diameter and loss of fibril size variation with increasing treatment temperature. Longitudinal sections of collagen fibrils showed increased fibril diameter and the loss of cross-striations in the treated groups. Thermally induced ultrastructural collagen fibril alteration is likely the predominant mechanism of tissue shrinkage caused by application of radiofrequency energy.

Animals↗