Holmium laser surgery

Evaluation of Safe Insertion Angles for Spinal Needles and Safe Intensity of the Holmium:YAG Laser during Percutaneous Laser Disc Ablations in Feline Cadavers

In the context of veterinary medicine, minimally invasive techniques for feline spinal surgery remain underexplored, particularly for percutaneous laser disc ablation (PLDA) when using the Holmium:YAG (Ho:YAG) laser. This study aimed to refine the application of the Ho:YAG laser in PLDA by determining the optimal laser intensity and safe insertion angles for the thoracic and lumbar intervertebral discs (IVDs) in cats. Through utilizing computed tomography (CT) for precise guidance, this research involved a cadaveric study of 10 cats to evaluate the spatial configurations that allow for safe needle insertions and effective laser ablation. Various energy settings of the Ho:YAG laser (20 J, 40 J, and 60 J) were tested to ascertain the balance between adequate disc vaporization and minimal adjacent tissue damage. The results demonstrate that a 40 J setting is the most effective in achieving significant disc decompression without compromising surrounding tissue integrity. Additionally, the CT scans proved crucial in confirming the accuracy of the needle placement and the safety of the laser application angles. This study established that the 40 J setting on the Ho:YAG laser, combined with CT-guided insertion techniques, offers a reliable method for PLDA, thus enhancing the safety and efficacy of feline spinal surgeries.

Direct 800 nm diode-pumped Holmium laser with broad pump wavelength range and temperature adaptability

We developed an 808 nm diode laser pumped composite Holmium laser via the integration of Tm-doped and Ho-doped YAG crystals into a single bulk structure. A maximum output power of 1.8 W at 2122 nm with near diffraction-limited beam quality was achieved for an absorbed pump power of approximately 7 W. Given that the pump wavelength is approximately 20 nm away from the absorption peak of the Tm-doped region of the crystal, pump wavelength adaptability of the Tm/Ho composite laser was effectively demonstrated. In this case, a pump range width in excess of 40 nm at approximately 800 nm was predicted by defining the pump spectrum of the gain medium. The temperature adaptability of the Ho laser was demonstrated by varying the cooling temperature from 9 °C to 27 °C. This resulted in Ho laser operation above 1.5 W with a power deviation below 10%. This work presents the experimental results for a compact assessable 2.1 μm laser without pump wavelength and operation temperature restrictions.

A comparison of combined arthroscopic triangular fibrocartilage complex debridement and arthroscopic wafer distal ulna resection versus arthroscopic triangular fibrocartilage complex debridement and ulnar shortening osteotomy for ulnocarpal abutment syndrome

PURPOSE

Treatment of ulnocarpal abutment (UAS) syndrome involves decompression of the pressure and impingement, or abutment of the ulnocarpal articulation. Debridement of triangular fibrocartilage complex (TFCC) tears alone in the patient with UAS may have a failure rate of as much as 25% to 30%. Ulnar shortening osteotomy (USO) can be an effective treatment of failed TFCC debridement. Good results have been reported with combined arthroscopic TFCC debridement and mechanical arthroscopic distal ulnar resection. Similar results have been reported with both ulnar shortening osteotomy and open wafer distal ulnar resections in the UAS patient. Because all of these treatment choices appear to yield similar relief of symptoms, determination of the optimal treatment protocol remains a point of debate. The purpose of this study was to evaluate 2 different surgical treatments for UAS.

TYPE OF STUDY

Retrospective review.

METHODS

Eleven combined arthroscopic TFCC debridement and arthroscopic distal ulna resections (arthroscopic wafer procedures; AWP) were compared with 16 arthroscopic TFCC debridement and USOs. All patients had diagnostic wrist arthroscopy and arthroscopic TFCC debridement. All patients presented with ulnar wrist pain or neutral or positive ulnar variance, and all experienced at least 3 months of failed conservative management.

RESULTS

At mean follow-up times of 21 and 15 months, respectively, 9 of 11 patients showed good to excellent results after arthroscopic TFCC debridement and AWP compared with 11 of 16 after arthroscopic TFCC debridement and USO. A statistically significant difference (P <.05) in the complication rates was identified, including secondary procedures and tendonitis. One secondary procedure and 2 cases of tendonitis were seen in the arthroscopic wafer group.

CONCLUSIONS

Combined arthroscopic TFCC debridement and arthroscopic wafer procedure provides similar pain relief and restoration of function with fewer secondary procedures and tendonitis when compared with arthroscopic TFCC debridement and USO, for the treatment of UAS.

LEVEL OF EVIDENCE

Level III.

Histological alterations after irradiation of cartilage using Ho:YAG laser

OBJECTIVE

The authors carried out an experimental study to evaluate the histological alterations after irradiation of cartilage using Holmium:YAG (Ho:YAG) laser VersaPulse Select 60 watts and Infra Tome Delivery Systems 30 degrees Handpiece (spot size at fiber tip 0.4 mm; Coherent Medical, Palo Alto, CA).

BACKGROUND DATA

Recently, some authors reported cases with articular cartilage damage following arthroscopic laser surgery in the knee joint for the treatment of articular cartilage or meniscal pathology.

MATERIALS AND METHODS

The cartilage specimens immersed in saline were exposed to Ho:YAG laser irradiation. The laser wavelength was 2.1 microm, and pulse duration was 250 microsec. Power settings were 0.2-1 joules per pulse and 10-15 Hz. Total laser energy used in these procedures was 1.5 K joules. During the procedures, the handpiece was used at an angle of 30 degrees and at a distance of 1 mm.

RESULTS

Electron microscopic evaluation demonstrated that the ultrastructure of the cartilage is preserved in both experiment and control groups.

CONCLUSION

When Ho:YAG laser is used in optimal dosage (optimal joule and Hertz) with optimal technique (keeping the handpiece at an appropriate angle and distance) and avoiding overtreatment, it does not cause cartilage damage.

Laser-assisted arthroscopic ulnar shortening

The purpose of this study is to evaluate arthroscopic ulnar shortening with the holmium:yttrium-aluminum-garnet (Ho:YAG) laser for the treatment of ulnocarpal abutment syndrome (UAS). This is a retrospective review of the experience of a single surgeon using this technique between 1994 and 2000. Unloading the ulnocarpal joint is the recognized treatment of UAS. Ulnar shortening via a diaphyseal osteotomy and plating (USO) has been used with good results; however, nearly 50% of patients will require hardware removal. Researchers have reported similar results between open distal ulnar resection (the wafer procedure) and USO for the treatment of UAS. Researchers have also reported similar results with mechanical arthroscopic distal ulnar resections (arthroscopic wafer distal ulnar resection [AWP]) for UAS. Eleven patients who underwent Ho:YAG laser-assisted arthroscopic distal ulnar resection were retrospectively evaluated. The average follow-up time was 31 months, with a range of 7 to 61 months. Evaluation using Darrow' s criteria revealed 64% excellent (7 of 11), 18% good (2 of 11), 9% fair (1 of 11), and 9% poor (1 of 11) results. The average return to work time was 4.7 months, with a range of 1.5 to 16 months. Complications included 1 repeat surgery for ulnocarpal scar formation, 2 cases of transient tendonitis, and 1 portal site erythema without drainage that was treated with antibiotics. One patient (the one with a poor result) has not returned to work for unrelated reasons. chi- square analysis (P <.05) was unable to identify a statistical difference between the reported results of arthroscopic wafer procedures, USOs, and open wafer procedures. We concluded that Ho:YAG laser-assisted arthroscopic ulna shortening procedures show similar results to those reported for arthroscopic wafer procedures, open wafer procedures, and USOs. Return to work times are similar to those reported by other researchers, as is the return to preoperative occupation rate. There is no need for late removal of hardware, as is sometimes associated with USO. Our experience has been that the Ho:YAG laser removes hyaline cartilage and subchondral bone rapidly and with little debris, and thus facilitates the ulna shortening procedure.

Complications of thermal energy in knee surgery--Part I

The use of thermal energy in knee surgery has many potentially exciting and useful applications. There is a growing body of literature that demonstrates the effects of these energy probes on different types of tissue. When contemplating the use of these surgical interventions in patients, it is important to recognize the potential limitations and complications that may arise.

Vastus lateralis release for painful bipartite patella

PURPOSE

The purpose of this study was to evaluate the efficacy of vastus lateralis release for painful bipartite patella. We have also compared the results of open method versus arthroscopic method using a holmium:YAG laser system (OmniPulse Holmium Laser System; Trimedyne Inc, Irvine, CA).

TYPE OF STUDY

This study was a nonrandomized control and cross-over trial.

METHODS

Fifteen patients with 17 painful bipartite patella who underwent vastus lateralis release were included in this study. The average age of patients was 14.3 +/- 2.2 years. In 7 knees of 6 patients, vastus lateralis release was performed through a skin incision over the bipartite fragment, and in 10 knees of 9 patients, we performed the procedure arthroscopically with the holmium:YAG laser. We assessed clinical and radiographic data of the patients chronologically in both groups.

RESULTS

In all patients, pain over the fragment disappeared within 4 weeks after the operation, and all returned to their previous sports activities at an average of 3.1 +/- 0.9 months postoperatively. Clinical assessment was classified as excellent in 13 knees and good in 4 knees. Bone union at 6 months after the operation was complete in 11 knees (64.7%) and incomplete in 6 knees (35.3%), and none of the knees was graded as not healed. Bone union in patients with an age of 15 or younger was significantly better than that in patients over 15 years of age (P <.05). Release under arthroscopy showed statistically better results in duration of knee effusion (P <.05), return of circumference of thigh (P <.05), and return of muscle strength (P <.05).

CONCLUSIONS

Because vastus lateralis release is less invasive surgery with good results, we conclude that this procedure can be a first choice of operative treatment for painful bipartite patella.

Matrix assessment of the articular cartilage surface after chondroplasty with the holmium:yttrium-aluminum-garnet laser. A long-term study

A long-term in vivo study was performed to assess biochemical changes after laser repair of articular cartilage. Forty New Zealand White rabbits were sacrificed 26 weeks after undergoing an articular cartilage chondroplasty with use of a holmium:yttrium-aluminum-garnet laser at 0.8 joules per pulse and a rate of 10 Hz. Glycosaminoglycan content in the repaired tissue decreased significantly with both perpendicular (19.59+/-5.6 microg hexosamin/mg of dry tissue) and tangential delivery (14.78+/-4.5 microg/mg) compared with the sham-treated tissue (39.6+/-5.0 microg/mg). Cellular viability was also significantly decreased. Sulfate incorporation was decreased to 203+/-142 cpm/mg of dry cartilage in the tangential mode and 461+/-209 cpm/mg in the tangential mode, compared with the sham at 1845 cpm/mg. Uptake of [3H]thymidine decreased to 463+/-473 cpm/mg of dry tissue and 455+/-170 cpm/mg in the tangential and perpendicular modes, respectively, compared with 2465 cpm/mg in the sham tissue. There were no significant differences between the tangential and perpendicular delivery modes in any assessments performed. The shortterm chondrocyte destruction previously noted in a 12-week study after laser treatment was not reversed during a longer-term 26-week study, and cellular viability was not recovered, suggesting that the loss of chondrocyte function may be permanent.

Histological and magnetic resonance imaging alterations after irradiation of meniscus using Holmium:YAG laser

OBJECTIVE

The authors performed an experimental and a prospective clinical study to evaluate the histological and magnetic resonance imaging (MRI) alterations after irradiation of meniscus using holmium:YAG (Ho:YAG) laser VersaPulse Select 60 watts and InfraTome Delivery Systems 30 degrees Handpiece (spot size at fiber tip 0.4 mm; Coherent Medical, Palo Alto, CA).

BACKGROUND DATA

Recently, some authors reported a few cases with articular cartilage damage or paraarticular osteonecrosis following arthroscopic knee surgery in which the laser was used to assist in the treatment of meniscal pathology.

METHODS

Meniscus specimens in saline immersion were exposed to Ho:YAG laser irradiation. The laser wavelength was 2.1 microm and pulse duration was 250 microsec. Power settings were 1-1.5 joules per pulse and 10-15 Hz. Total laser energy used in these procedures was 2, 3.5, and 6 K joules. Eight patients with meniscal problems underwent arthroscopic partial meniscectomy using Ho:YAG laser. Total laser energy used for these surgeries was 1.5-2.5 K joules. MRI was performed preoperatively and at 6 months postoperatively.

RESULTS

At higher energy levels (more than 3 K joules), separation of the gap between the collagen fibers, and a three-dimensional dispersion in the striation were observed on electron microscopic evaluation of meniscus specimens. No patient had abnormal signals in MRI (a sign of articular cartilage damage or osteonecrosis) following arthroscopic laser surgery.

CONCLUSION

When higher energy level is required, conventional instruments should be preferred in the treatment of meniscal lesions. Laser should be reserved for the posteriorly located and smaller meniscal lesions.

Patient Satisfaction after Thermal Shrinkage of the Glenohumeral-Joint Capsule

Objective:

To determine whether patients were satisfied after thermal shrinkage on the capsule of the glenohumeral joint (GHJ).

Design and Setting:

The affected shoulder was assessed preoperatively and 2 months postoperatively. The assessment evaluated pain on activities of daily living (ADLs), physical activity level, satisfaction with shoulder function, and a modified UCLA pain scale.

Subjects:

Eight athletes, 4 men and 4 women, with a mean age of 21 years, participated. Each had sustained a traumatic injury to the GHJ resulting in multidirectional instability.

Measurements:

Subjects were evaluated preoperatively and 2 months postoperatively for GHJ laxity and labral deformity. Goniometric measurements of flexion/extension, abduction/adduction, and internal/external rotation of the GHJ were completed.

Results:

Six of the 8 subjects had reduced pain. Active extension increased significantly in 7. ADLs were all improved. All 8 subjects were satisfied with the thermal-shrinkage procedure.

Conclusions:

Thermal shrinkage of the capsule of the GHJ results in patient satisfaction and reduced pain.

Thermal capsular shrinkage: Basic science and clinical applications

Recently, the use of thermal energy to shrink the redundant glenohumeral joint capsule in patients with instability has generated a great deal of interest. Proponents assert that the procedure avoids the need for an open stabilization and it may be used as an adjunct to an open or arthroscopic capsulolabral repair. The use of nonablative thermal energy to shrink soft-tissue collagen appears to induce ultra-structural and mechanical changes at or above 60 degrees C. The microscopic changes reflect the unwinding of the collagen triple helix and loss of the fiber orientation. The fibrils contract into a shortened state and reactive fibroblasts have been shown to grow into this treated area and synthesize the collagen matrix. The biomechanical properties of the tissue do not appear to be detrimentally altered if shrinkage is limited to less than 15% and if ablation or excess focal treatment is avoided. The endpoint of optimal shrinkage is not known and clinical estimations of tissue changes and volumetric reduction are used as guides to treatment. The first clinical follow-up study was only recently published in the peer-reviewed literature and prior preliminary reports were optimistic regarding the use of thermal energy for the treatment of glenohumeral instability. Thermal capsular shrinkage has been used as an adjunct to a capsulolabral repair, as well as an isolated treatment for the disorders of internal impingement and multidirectional instability. Additional evaluation is necessary to determine the optimal quantity of energy needed for tissue shrinkage without inadvertent tissue destruction. The long-term clinical effect, mechanical properties, and durability of the newly produced collagen need to be analyzed further. The basic science and clinical applications of this newly applied technology are reviewed in this article.

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.

Quantification of laser-induced cartilage injury by confocal microscopy in an ex vivo model

BACKGROUND

The application of lasers in orthopaedic surgery is increasing. However, some investigators have reported that osteonecrosis may occur after laser meniscectomy. The objective of the present study was to evaluate the effect of laser wavelength and energy on cartilage injury in an ex vivo model.

METHODS

Fresh bovine articular cartilage was exposed to either holmium:yttrium-aluminum-garnet (Ho:YAG) or erbium:YAG-laser (Er:YAG) irradiation. Both lasers were operated in a free-running mode and at a pulse-repetition rate of 8 Hz. The effect of laser treatment at several energy levels (Er:YAG at 100 and 150 mJ and Ho:YAG at 500 and 800 mJ) was examined. For each light source and energy level, ten cartilage samples were assessed by conventional histological analysis and by confocal microscopy. Thermal damage was assessed by determining cell viability.

RESULTS

The extent of thermal damage demonstrated by confocal microscopy was much greater than that demonstrated by histological analysis. The extent of thermal injury after Ho:YAG-laser irradiation was much greater than that after Er:YAG-laser irradiation, which was associated with almost no damage. In addition, the ablation depth was greater after treatment with the Er:YAG laser than after treatment with the Ho:YAG laser.

CONCLUSIONS

In the present study, histological analysis underestimated thermal damage after laser irradiation. In addition, our findings highlighted problems associated with use of high-power settings of Ho:YAG lasers during arthroscopic surgery.

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.

Thermally induced shrinkage of joint capsule

Thermal shrinkage of collagen currently is being used in orthopaedic surgery to treat ligamentous laxity. Understanding the kinetics of collagen shrinkage is key to revealing the events that take place during application of thermal energy. To elucidate the thermokinetic properties of collagen, punch biopsies of bovine joint capsule were immersed in a heated saline bath at temperatures between 20 degrees and 90 degrees C for periods up to 60 minutes. The resulting tissue thermal shrinkage was measured by the change in the cross-sectional area of the specimens. Only a small amount of shrinkage occurred at temperatures below 63 degrees C, and increasing amounts and rates of shrinkage were seen at temperatures between 63 degrees and 72 degrees C. The denaturation kinetics of bovine knee collagen, which could be described by a first order reaction rate, had an activation energy of 2.3 x 10(5) kJ/mol.

Safe parameters for laser chondroplasty of the knee

BACKGROUND AND OBJECTIVE

The purpose of this study is to summarize our use of the Holmium laser as a tool in performing chondroplasties of the knee and to determine whether any untoward affects developed at the site of laser application.

STUDY DESIGN/MATERIALS AND METHODS

A retrospective review of 504 laser chondroplasties of the medial femoral condyle was done. Laser parameters and the average number of joules to perform the chondroplasties were recorded. The average follow-up was 11 months.

RESULTS

Preoperative MRI interpretation indicated that 8% of the patients had osteonecrosis prior to surgery. 88% of the patients were satisfied with the procedure. All failures were evaluated by X-ray, MRI, bone scan, or biopsy of the medial femoral condyle. No new cases of osteonecrosis were determined.

CONCLUSION

No new cases of osteonecrosis were documented of the medial femoral condyle following laser chondroplasty utilizing the parameters in this study. The Holmium laser remains a safe and efficacious tool in performing chondroplasty.

Cost-benefit comparison: holmium laser versus electrocautery in arthroscopic acromioplasty

This prospective study was designed to measure the costs and benefits of using a laser rather than electrocautery for soft tissue resection during arthroscopic shoulder decompression. Forty-nine shoulders with refractory Neer stage II impingement (persistent fibrosis and tendinitis) were divided into 2 groups. The composition of the 2 groups was similar with regard to sex, worker's compensation status, dominant arm involvement, duration of symptoms, and length of conservative treatment. In one group, electrocautery was used to ablate the bursa and periosteum, release the coracoacromial ligament, and maintain hemostasis. In the other group, a laser was used in place of electrocautery. Patients had been evaluated preoperatively with 2 functional scoring systems. The patients were reexamined at 1 week and at 1, 2, 3, 6, and 12 months after surgery. There were no differences between the groups with regard to functional outcome or satisfaction. There was also no difference in terms of estimated blood loss or operative time. However, there was a statistically significant difference in total hospital charges between groups, with the laser group having a 23% higher hospital bill. On the basis of these results, it is concluded that there was no medical benefit to laser-assisted arthroscopic subacromial decompression but there was an increased monetary cost.

Electrothermally-assisted capsular shift

The marriage of biomedical instrumentation and patient care has once again proven itself successful. The ETAC is a new procedure with various potential applications. Despite its embryonic stage, this procedure is being used by a handful of shoulder surgeons who are cautiously pursuing new and improved ways to prevent the common and debilitating diagnosis of shoulder instability. Follow-up thus far is short, and the current literature lacks studies that compare the time-honored conventional standard of open stabilization to this new procedure. However, those surgeons who have been using this device are optimistic about its role in the future repair of shoulder injuries.

Holmium: YAG laser-induced aseptic bone necroses of the femoral condyle

In laser-controlled cartilage-ablation arthroplasties, the attention focuses more and more on the depth effects of the various lasers, especially as heat necroses of the cartilage and even in places of the bone were found in animal experiments. For the first time, two cases of holmium: YAG laser-induced aseptic bone necrosis of the femoral condyles after cartilage ablation are described.

Effects of holmium: YAG laser energy on cartilage metabolism, healing, and biochemical properties of lesional and perilesional tissue in a weight-bearing model

Comparison of perilesional cartilage, lesional repair tissue, and subchondral bone activity 6 months after application of holmium-yttrium-aluminum-garnet (Ho:YAG) laser energy to chronic (10 week) induced 10-mm full-thickness (FT) circular articular cartilage craters followed by 6 months' intermittent active motion (IAM) in a free exercise environment was investigated. The 2.1-microns wavelength was delivered in hand-controlled near-contact mode by arthroscopic surgery in a saline medium. Bilateral arthroscopy was performed on normal antebrachiocarpal, intercarpal, and metacarpophalangeal joints of six adult horses. Full-thickness craters were created in nine sites per limb on weight-bearing articular surfaces with a motorized bur. Right limb craters served as sham operated controls. Animals were killed at 10 weeks after FT crater creation (n = 2), and at 24 weeks (6 months) after laser energy application (n = 4). Histological analysis using hematoxylineosin (HE) and Safranin-O staining consisted of a modified Mankin grading of perilesional cartilage and lesional repair tissue scoring. Biochemical analysis was performed for cellularity and glycosaminoglycan (GAG) synthesis. Histological analysis showed clustering of chondrocytes or perilesional zonal cloning (PZC) in 83% of laser-treated lesions and in no control lesions. No differences were observed between treated and control lesional repair activity. Laser-treated perilesional cartilage showed a significant (P < .02) decrease in GAG synthesis. No adverse effects to distant cartilage were observed after application of laser energy regarding cell proliferation or GAG synthesis. Significance of decreased GAG synthesis in treated perilesional cartilage and perilesional zonal cloning of chondrocytes in treated cartilage is unknown. Additional study of Ho:YAG laser energy application to cartilage and subchondral bone is needed before its application in the surgical management and repair of cartilage damage.

Delayed articular cartilage slough: two cases resulting from holmium:YAG laser damage to normal articular cartilage and a review of the literature

We present two cases referred from other physicians with chondral damage and cartilage slough secondary to use of the holmium:YAG laser during knee arthroscopy. The first patient had a partial lateral meniscectomy, which was done with a 20-W Ho:YAG laser. The patient never fully recovered and underwent a second arthroscopy that revealed full-thickness cartilage defects of the lateral femoral condyle. The second patient had debridement of Outerbridge grade III changes of the lateral tibial plateau and patella, as well as a partial lateral meniscectomy using a Ho:YAG laser. The patient developed recurrent symptoms, and when a second arthroscopy was performed, new degenerative changes to the lateral femoral condyle were noted with large areas of cartilage loss. A careful look needs to be taken at the limited use of lasers until further randomized prospective studies are carried out comparing patient outcomes, cost, and long-term complications.

Treatment of inflammatory arthritis by synovial ablation: a comparison of the holmium: YAG laser, electrocautery, and mechanical ablation in a rabbit model

BACKGROUND AND OBJECTIVE

Although the majority of patients with immune-mediated inflammatory arthritis are managed conservatively, some patients may require synovectomy if they have persistent pain secondary to chronic unresponsive swelling of a joint. In this study, three methods of synovial ablation using laser energy, electrocautery, and mechanical debridement were compared in an in vivo chronic synovitis rabbit model. STUDY DESIGN/MATERIALS, AND METHODS: In the first phase of this study, the optimal laser energy/pulse frequency combination for synovial ablation in this model was determined. In the study's second phase, 48 mature rabbits were then divided into four equal groups: laser synovectomy, electrocautery synovectomy, mechanical synovectomy, and control. Chronic synovitis was induced in both stifles of all treatment groups and in the right stifle of the control rabbits. Synovectomy was performed on one stifle of each rabbit; the contralateral stifle served as a sham-operated control. Six rabbits per group were euthanized 2 weeks and 3 months after surgery, respectively.

RESULTS

There were no differences among groups in synovial fluid parameters, except at 2 weeks, when the electrocautery group had significantly more white blood cells than the laser and mechanical debridement groups. Histologic examination revealed that mechanical debridement resulted in significantly more synovial hemorrhage, capillary dilatation, plasma cell infiltration, lymphocyte infiltration, joint capsular defects, and poorer synovial ablation than ablation achieved with either laser energy or electrocautery.

CONCLUSION

Laser energy and electrocautery achieved similar results when used for ablative purposes, although electrocautery did not achieve the same degree of synovial ablation as laser energy.

Holmium:YAG laser endoscopic sinus surgery: a randomized, controlled study

Although surgical lasers were introduced to the field of otolaryngology more than 20 years ago, their use in rhinologic surgery has remained relatively limited. With the development of the holmium:yttrium-aluminum-garnet (YAG) laser, a device is now available that offers those features necessary for effective sinus surgery:precise bone ablation, efficient soft tissue coagulation, and fiberoptic transmission. This solid-state laser of 2.1-microns wavelength can be coupled with endoscopic instrumentation for the surgical treatment of sinus disease. This study was conducted to determine the clinical efficacy of the holmium:YAG laser for endoscopic sinus surgery. A microscopic analysis of laser-treated sinus tissue was also performed in an attempt to determine the histologic basis of the observed clinical findings. In a prospective, randomized, controlled, single-blinded study, 32 consecutive patients underwent endoscopic sinus surgery using the holmium:YAG laser on one side of the nose and conventional endoscopic instrumentation on the other side. Patients rated symptoms for each side of the nose at 1 week, 1 month, 3 months, 6 months, and 2 years after surgery. Healing parameters were similarly rated by the surgeon. Until the study was completed, patients were not told which side of the nose had been treated with laser surgery. No intraoperative complications occurred. The mean intraoperative blood loss was 24.6 mL less on the laser-treated side of the nose than on conventionally treated side (P < .001). At 1 week after surgery, there was increased mucosal edema on the laser-treated side (P < .01). Crust formation was greater on the conventionally treated side at 1 week and was greater on the laser-treated side at 1 mouth (P < .01). Improvements in symptoms of pain, congestion, and drainage were equivalent for both treatment modalities (P < .001). Microscopic analysis demonstrated the ability of the holmium:YAG laser to remove tissue in relatively thin layers with ablation depths of 260 +/- 8.2 microns, 286 +/- 9.4 microns, and 341 +/- 20.4 microns per pulse at energy levels of 0.5, 1.0, and 1.5 J, respectively. A zone of thermal necrosis extending up to 1 mm beyond the site of laser impact was thought to correlate with the increased postoperative edema observed on the laser-treated side. Endoscopic sinus surgery with the holmium:YAG laser is as effective as nonlaser techniques in relieving the symptoms of chronic sinusitis. Laser surgery offers improved intraoperative hemostasis, but it causes increased postoperative tissue edema. The holmium:YAG laser provides the surgeon with an additional tool for the performance of safe, effective sinus surgery.