Arthroscopic shoulder surgery with three different laser systems: an evaluation of laser applications

Ablation of temporomandibular joint structures of a pig with a fibre-guided 308nm excimer laser light—an in vitro investigation

PURPOSE

The present in vitro investigation was carried out to assess the efficacy of treatment with 308 nm excimer laser radiation applied to the structures of the temporomandibular joint of a pig. Laser parameters suitable to ensure adequate clinical efficiency with only minor thermal damage to the surrounding tissues were to be determined.

MATERIAL AND METHODS

Tissue structures of the temporomandibular joint (cortical and cancellous bone, cartilage, disc and muscle) were extracted from freshly killed pigs and served as specimens. The specimens were embedded in polymethylmethacrylate. The laser light was applied after horizontal sectioning and measurement of thickness. The number of impulses that were necessary to perforate the specimen was counted and the rate of ablation determined. In addition, the irradiated surface was investigated histologically and the degree of tissue alteration was evaluated.

RESULTS

The lowest energy threshold for ablation was found at an energy density of 0.8 J/cm2. Depending on the type of tissue, the maximum rate of ablation was evaluated as 1.7-6.3 microm/pulse. The depth of the thermal alteration to the surrounding tissue was about 30-70 microm.

CONCLUSION

The guidable 308 nm excimer laser light offers a combination of precise tissue ablation with only minimal thermal damage to the surrounding tissue.

Scattering and thermal lensing of 2.12- mum laser radiation in biological tissue

We studied light propagation of holmium:YAG laser radiation (lambda = 2.12 mum) by measuring the two-dimensional laser beam profile before and after propagation through a tissue sample with a modified fast-temperature-measurement technique. The comparison between water and cartilage tissue allowed us to differentiate between beam broadening caused by formation of a thermal lens and broadening due to light scattering. In water, beam propagation is influenced by formation of thermal lensing, whereas in cartilage the broadening was caused by a combination of light scattering and thermal lensing. Additionally, we discovered that the observed effects are subject to dynamic changes during the laser-tissue interaction.

The healing effects on the biomechanical properties of joint capsular tissue treated with Ho:YAG laser: An in vivo rabbit study

PURPOSE

The objective of this study was to evaluate the healing response, after thermal treatment with a Ho:YAG laser, on the biomechanical properties of capsular soft tissue.

TYPE OF STUDY

Before and after trial.

METHODS

Forty-five New Zealand white rabbits were used in this study. A medial peripatellar retinacular thermal capsuloplasty using a Ho:YAG laser and a lateral peripatellar retinacular release was performed on 1 knee of each rabbit. The contralateral knee served as a control and had a lateral release of the retinaculum only. The temperature of the medial retinaculum was maintained at 55 degrees C +/- 5 degrees C during treatment. The medial peripatellar retinaculum was evaluated at 0, 6, and 12 weeks postoperatively. Tensile testing of the medial retinaculum and a biomechanical assessment evaluating the structural and material properties were performed.

RESULTS

The ultimate load (force) of the medial retinaculum was 70%, 56%, and 84% of control at 0, 6, and 12 weeks, respectively, after the procedure. The stiffness (force/deformation) of the medial retinaculum was 83% of control at 0 weeks, 54% at 6 weeks, and 85% at 12 weeks. The ultimate stress (force/area) of the medial retinaculum also showed a significant reduction at 0 and 6 weeks postoperatively, 63% and 62% of control, respectively. By 12 weeks, the ultimate stress was 83% of control.

CONCLUSIONS

Thermal treatment of the medial retinaculum with a Ho:YAG laser results in soft tissue with significantly diminished biomechanical properties after treatment. The results of this study suggest that a 12-week period of minimal stress on the capsular tissues should follow a thermal capsuloplasty procedure.

Arthroscopic subacromial decompression with a holmium:YAG laser: review of the literature

BACKGROUND

The Australian Safety and Efficacy Register of New Interventional Procedures-Surgical (ASERNIP-S) undertook to systematically review the literature regarding arthroscopic subacromial decompression (ASD) using a holmium:YAG laser for patients with impingement syndrome, with respect to the safety and efficacy of the procedure.

METHODS

Studies on ASD with a holmium:YAG laser were identified using MEDLINE (1984 to July 2000), EMBASE (1974 to August 2000) and Current Contents (1993 to week 33 2000). A number of search terms were used: (laser and shoulder) and (surgery or arthroscop* or acromioplasty or orthopaed* or orthoped* or subacromial decompression or impingement syndrome). The Cochrane Library was searched from 1966 to issue 3 2000, using the search terms 'shoulder and surgery'. Human studies were included for patients with impingement syndrome but without full-thickness rotator cuff tears or rheumatological disorders, and where shoulder pain had been experienced for more than 3 months. A surgeon and reviewer independently assessed the retrieved articles for their inclusion in the review.

RESULTS

Seven papers were identified that related to ASD with a holmium:YAG laser. None of the papers for review offered high-quality evidence. There were no properly designed randomized controlled studies. The highest level of evidence came from time series studies. No quantitative analysis could be undertaken for this review.

CONCLUSIONS

Given the extremely low level of evidence available for this procedure it was recommended that further research be conducted to establish the safety and efficacy of the technique. This reinforces the conclusion reached in the Cochrane review of interventions for shoulder pain where insufficient evidence was found to either support or refute the efficacy of other interventions for shoulder pain.

The holmium:yttrium-aluminum-garnet laser in wrist arthroscopy: a five-year experience in the treatment of central triangular fibrocartilage complex tears by partial excision

Arthroscopic debridement of the articular disk is an accepted method for the treatment of symptomatic central tears of the triangular fibrocartilage complex. Current techniques use punches, knives, and shavers to debride the torn disk back to a stable peripheral rim. The holmium:yttrium-aluminum-garnet laser offers an alternative method for disk debridement with potential advantages of enhanced speed, precision, and hemostasis. We present a retrospective review of 35 patients who underwent arthroscopic laser debridement for a Palmer type IA tear in the triangular fibrocartilage complex. Overall response to treatment was good to excellent in 68% of patients and return to work was seen in 88%. One patient developed a deep wound infection. Clinical results after arthroscopic laser debridement are comparable to those reported by other investigators using conventional techniques.

Arthroscopic treatment of anterior-inferior glenohumeral instability. Two to five-year follow-up

BACKGROUND

Previous studies on arthroscopic treatment of anterior-inferior glenohumeral instability have focused on the repair of lesions of the anterior-inferior aspect of the labrum (Bankart lesions) and have demonstrated failure rates of as high as 50 percent. The current investigation supports the concept that anterior-inferior instability is associated with multiple lesions and that success rates can be increased by treating all of the lesions at the time of the operation. We present the results of arthroscopic treatment of anterior-inferior gleno-humeral instability after a minimum duration of followup of two years.

METHODS

The study group consisted of fifty-three patients who had a mean age of thirty-two years (range, fifteen to fifty-eight years) at the time of the operation. There were forty-four male and nine female patients. The mean interval from the time of the operation to the final follow-up evaluation was thirty-three months (range, twenty-six to sixty-three months). The scores on the American Shoulder and Elbow Surgeons (ASES) Shoulder Index and the rating systems of Constant and Murley, Rowe et al., and the University of California at Los Angeles (UCLA) were recorded preoperatively and at the time of the final follow-up.

RESULTS

Preoperatively, none of the patients had an overall rating of good or excellent according to the system of Rowe et al.; however, 92 percent (forty-nine) of the fifty-three patients had a rating of good or excellent at the time of the final follow-up. The mean score improved from 45.5 points to 91.7 points on the ASES Shoulder Index, from 56.4 points to 91.8 points with the system of Constant and Murley, from 11.3 points to 91.9 points with the system of Rowe et al., and from 17.6 points to 32.0 points according to the UCLA Shoulder Score (p = 0.001 for all comparisons). The mean passive external rotation with the shoulder in 90 degrees of abduction measured 88.2 degrees. Thirty-four of thirty-eight patients returned to their desired level of sports activity following the operation. Four patients who had persistent instability were considered to have had a failure of the index operation, and one of them had a second operative procedure.

CONCLUSIONS

The results of the present study suggest that our technique of arthroscopic treatment of anterior-inferior glenohumeral instability is better than previous arthroscopic techniques and is equivalent to open repair. We believe that the improved rate of success demonstrated in the present study was the result of repair not only of the anterior-inferior (Bankart) lesion but also (where necessary) of inferior and superior labral tears. Additionally, soft-tissue tension within the capsule and ligaments was corrected with use of a suture technique but was supplemented by laser thermal capsulorrhaphy in forty-eight of the fifty-three shoulders. Rotator interval repair was considered a critical factor in fourteen of the fifty-three shoulders.

Glenohumeral joint range of motion and rotator cuff strength following arthroscopic anterior stabilization with thermal capsulorraphy

STUDY DESIGN

Single-session, posttest only, descriptive analysis of range of motion (ROM) and strength.

OBJECTIVES

To measure ROM and strength approximately 12 weeks following arthroscopic anterior stabilization of the glenohumeral joint with thermal capsulorraphy.

BACKGROUND

Treatment of the patient with anterior, unidirectional glenohumeral joint instability often includes surgical stabilization. Current methods focus on arthroscopic stabilization and early ROM and strengthening to restore normal function to the upper extremity.

METHODS AND MEASURES

Twenty patients diagnosed with unidirectional shoulder instability (mean age 24.5 years, SD = 8.48) underwent a postoperative rehabilitation program following unilateral arthroscopic shoulder stabilization with thermal capsulorraphy. Objective testing including ROM and isokinetic internal rotation (IR) and external rotation (ER) strength at 90, 210, and 300 degrees/s was performed 12 weeks postoperatively.

RESULTS

Ten patients had a complete return of shoulder flexion ROM at 12 weeks. There were deficits compared to the noninjured extremity in postoperative glenohumeral joint mean abduction (9.8 +/- 12.7 degrees), IR (8.4 +/- 15.0 degrees), and ER (13.1 +/- 14.4 degrees). Isokinetic testing showed a complete return of ER strength on the postoperative extremity compared to the uninjured extremity for 12 patients with a 4% (+/- 21.1%) mean deficit measured in IR strength at the slowest testing velocity. No significant difference was found between extremities in the external/internal rotation ratios.

CONCLUSION

Postoperative rehabilitation emphasizing progressive ROM and rotator cuff and scapular strengthening has produced favorable results in patients 12 weeks postoperatively with respect to glenohumeral joint ROM and IR and ER strength. Further research and follow-up is required to obtain long-term outcomes with respect to patient satisfaction and stability of the glenohumeral joint following this arthroscopic procedure.