Reduction of de novo postsurgical adhesions by intraoperative precoating with Sepracoat (HAL-C) solution: a prospective, randomized, blinded, placebo-controlled multicenter study. The Sepracoat Adhesion Study Group

OBJECTIVE

To assess the efficacy and safety of Sepracoat (HAL-C; Genzyme Corporation, Cambridge, MA) solution in reducing the incidence, severity, and extent of de novo adhesion formation at sites without direct surgical trauma or adhesiolysis at the time of gynecologic laparotomy.

DESIGN

Prospective, randomized, blinded, placebo-controlled multicenter study. Patients underwent gynecologic procedures via laparotomy; approximately 40 days later, surgeons assessed their adhesions during second-look laparoscopy.

SETTING

Twenty-three North American institutions.

PATIENT(S)

Two hundred seventy-seven women for safety evaluations; 245 women for efficacy studies.

INTERVENTION(S)

Intraoperative serosal coating with Sepracoat (treatment) or phosphate-buffered saline (placebo) after opening of the abdominal cavity, after irrigation or every 30 minutes during surgery, and at the completion of surgery.

MAIN OUTCOME MEASURE(S)

Incidence, severity, and extent of de novo adhesions to 23 intraabdominal sites.

RESULT(S)

The Sepracoat group had a significantly lower incidence of de novo adhesions than the placebo group as assessed by the proportion of sites involved (0.23 +/- 0.02 versus 0.30 +/- 0.02, respectively) and the percentage of patients without de novo adhesions (13.1% versus 4.6%, respectively), as well as significantly reduced adhesion extent and severity. Sepracoat was well tolerated, with a safety profile nearly identical to that of the placebo.

CONCLUSION(S)

Sepracoat was significantly more effective than placebo and was safe in reducing the incidence, extent, and severity of de novo adhesions to multiple sites indirectly traumatized by gynecologic surgery via laparotomy.

Evaluation of collagen gel and hyaluronic acid as vitreous substitutes

We evaluated alkaline-solubilized collagen, hyaluronic acid (HA), and a substance formed from mixing both materials as vitreous substitutes in the rabbit. Fluorescein isothiocyanate (FITC)-labeled collagen (2%), fluorescein-labeled HA (FLHA, 1%), or the mixture was injected into the rabbit vitreous after vitrectomy. After 3 months, histologic study revealed that the substitutes caused no adverse effects on the ocular tissue. Kinetic studies showed that the half-lives of FITC-collagen, FL-HA, and the mixed substance were 5.70, 2.09, and 8.41 days, respectively. The results indicated that HA enhances the collagen half-life. The concomitant of collagen and HA is safe and effective for 3 months in rabbit's eye as a vitreous substitute, and the mixture is capable of tamponade.

An open study to assess the efficacy and safety of topical 3% diclofenac in a 2.5% hyaluronic acid gel for the treatment of actinic keratoses

BACKGROUND

Actinic keratoses are potential precursors of invasive squamous cell carcinoma; therefore, treatment is often recommended. Current topical treatments may cause considerable discomfort, pain, or skin irritation. This study was established to explore the role, if any, of topical 3% diclofenac in 2.5% hyaluronic acid gel in the management of actinic keratoses.

OBSERVATIONS

An open-label study was conducted of topical 3% diclofenac in 2.5% hyaluronic acid gel applied to 1 or more actinic keratoses. Patients were instructed to apply 1.0 g of the gel twice daily for as many as 180 days. Treatment was stopped earlier than 180 days if lesions were assessed as cleared. Twenty-nine adults were treated for periods of 33 to 176 days (median, 62 days). Of the 29 subjects, 27 were reevaluated 30 days after drug therapy discontinuation. Of the 27 patients, 22 (81%) had a complete response and another 4 (15%) showed marked clinical improvement. The preparation was generally well tolerated, although in 7 patients (24%) an irritant-type contact dermatitis developed, which was confined to the treatment site.

CONCLUSION

Topical 3% diclofenac in 2.5% hyaluronic acid gel may be a clinically useful topical agent for the treatment of actinic keratoses.

Slow-acting, disease-modifying osteoarthritis agents

There is evidence to suggest that tetracyclines have benefit beyond their antimicrobial activity. The ability to inhibit metalloproteinase activity may provide a disease-modifying effect in OA, and available data suggest that further investigation is warranted. Controlled, double-blind, prospective clinical studies have not been completed. The canine cruciate ligament transection model studies are frequently cited as the most convincing in vivo evidence of a benefit of oral tetracycline therapy for the treatment of OA. Until more evidence becomes available, the use of tetracyclines as therapeutic agents for OA should be considered investigational.

Prospective, randomized trial of Microvisc and Healon in routine phacoemulsification

PURPOSE

To compare the safety and efficacy of the new sodium hyaluronate viscoelastic, Microvisc, with those of Healon in routine phacoemulsification.

SETTING

York Finch Eye Associates and York Finch General Hospital, Toronto, Ontario, Canada.

METHODS

An unmasked, prospective, randomized clinical trial of 100 eyes in 100 patients having routine phacoemulsification and intraocular lens implantation was conducted to compare the safety and efficacy of Microvisc with those of Healon. Visual acuity, corneal thickness, and intraocular pressure were assessed preoperatively and at 6 hours, 1 and 5 days, and 1 and 6 months postoperatively.

RESULTS

There were no statistically significant differences between the two treatment groups at any follow-up

CONCLUSION

Based on the parameters assessed, both viscoelastic products were safe and provided comparable outcomes.

Evaluation of hylan b gel as a soft-tissue augmentation implant material

BACKGROUND

The ideal soft tissue augmentation material should be an inert, safe, volume-filling material that is easy to use and remains in place over time. Hylan b gel, a cross-linked hyaluronic acid, may have many of these characteristics.

OBJECTIVE

We assessed the potential value of hylan b gel as a soft tissue augmentation material.

METHODS

A 12-month guinea pig model was used to investigate the tissue effects of hylan b gel versus "collagen" controls.

RESULTS

Hylan b gel was found to be biologically compatible and stable in dermal tissues. At 1 year, only hylan b gel implants were evident (12 of 16 test sites).

CONCLUSION

In this model hylan b gel performed favorably when compared with the most commonly used soft-tissue augmentation products. The material possesses many desirable implant material characteristics.

Relationship between postoperative intraocular pressure elevation and residual sodium hyaluronate following phacoemulsification and aspiration

PURPOSE

To investigate the relationship between postoperative intraocular pressure (IOP) elevation and the amount and viscosity of sodium hyaluronate remaining in the anterior chamber after phacoemulsification and aspiration (PEA).

SETTING

Hachioji Medical Center and Tokyo Medical College Hospital, Tokyo, Japan.

METHODS

In 107 eyes, washout (irrigation and aspiration [I/A]) of sodium hyaluronate was performed for randomly assigned durations of 5, 10, or 20 seconds following PEA and intraocular lens (IOL) implantation. At the conclusion of washout, the flow from the I/A tip was reversed and a sample of the irrigating solution obtained from the anterior chamber. The residual sodium hyaluronate concentration was measured by sandwich assay. The kinematic viscosity of the sample was calculated from a regression equation derived from measured viscosities of standard hyaluronate solutions of various concentrations.

RESULTS

The preoperative mean IOP in the groups that received 5-, 10-, and 20-second washout was 11.9, 10.9, and 11.6 mm Hg, respectively. The mean IOP on the first postoperative day in the 5-second group was significantly higher (P = .001, Kruskal-Wallis test) than those in the 10- and 20-second groups (10.8 and 11.6 mm Hg, respectively). A significant correlation was observed between residual hyaluronate concentration and IOP on the first postoperative day (Spearman's rank correlation coefficient 0.319, n = 80, P = .045) and also between kinematic viscosity and IOP on the first postoperative day (one-factor analysis of variance, P < .001).

CONCLUSION

The sodium-hyaluronate-induced IOP elevation is related to its viscosity as well as to its high molecular weight. Washout times of at least 10 seconds are desirable to prevent IOP elevation.

Comparison of topical timolol gel to oral acetazolamide in the prophylaxis of viscoelastic-induced ocular hypertension after penetrating keratoplasty

PURPOSE

Viscoelastic-induced ocular hypertension following penetrating keratoplasty (PK) may result in endothelial cell loss and optic nerve damage.

METHODS

In a prospective, randomized, masked trial, two doses of oral sustained-release acetazolamide were compared to a single dose of topical 0.5% timolol gel after 40 PKs.

RESULTS

The mean preoperative intraocular pressure (IOP) was 17.4 mm Hg for the oral acetazolamide group and 16.7 mm Hg for the timolol gel group. The mean IOP on the first postoperative day was 17.9 mm Hg with oral acetazolamide and 12.9 mm Hg with timolol gel. One patient developed significant adverse reactions with oral acetazolamide; there were no adverse reactions with timolol gel.

CONCLUSION

Prophylactic use of timolol gel for viscoelastic-induced ocular hypertension after PK appears to offer better IOP control than oral acetazolamide, with potentially fewer adverse systemic effects.

Comparison of viscoelastic substances used in phacoemulsification

PURPOSE

To evaluate the usefulness of four viscoelastic agents during phacoemulsification: 2% hydroxypropylmethylcellulose (HPMC) (Methocel), 3% sodium hyaluronate with 4% chondroitin sulfate (Viscoat), 1% sodium hyaluronate (Healon), 1.4% sodium hyaluronate (Healon GV).

SETTING

Eye Clinic, Kreiskrankenhaus Bad Hersfeld, Germany.

METHODS

Two hundred patients, divided into four groups of 50 patients, received one of the viscoelastic substances during phacoemulsification and posterior chamber intraocular lens implantation. Patients were followed for 1 month. Visual acuity and intraocular pressure (IOP) were measured. The following were subjectively evaluated for each viscoelastic: corneal findings, anterior chamber reaction, visibility of intraocular structures and retention time during phacoemulsification, space maintaining ability, and removability and ease of injection.

RESULTS

Postoperative IOP and visual acuity were comparable among the four groups. Viscoat tended to trap nuclear fragments and air bubbles during the phacoemulsification procedure, which decreased visibility during surgery. Space maintenance and injection ease were significantly better with Healon and Healon GV.

CONCLUSION

The high molecular weight viscoelastics (Healon and Healon GV) performed better as viscosurgical tool during cataract surgery using phacoemulsification.

Viscosupplementation with hylan for the treatment of osteoarthritis: findings from clinical practice in Canada

OBJECTIVE

To evaluate viscosupplementation with intraarticular hylan G-F 20 in current clinical practice.

METHODS

A retrospective study of all patients with osteoarthritis of the knee treated with hylan by 5 Canadian clinicians over a period of 2.5 years.

RESULTS

A total of 1537 injections were performed in 336 patients involving 458 knees. The overall response and the change of activity level were judged better or much better for 77 and 76% of the treated knees after the first course of treatment (3 weekly injections), and 87 and 84% after a 2nd course. The mean time elapsing between the first and 2nd course, 8.2 +/- 0.5 months, is an evaluation of the duration of benefits. Local adverse events were observed in 28 patients (32 knees), with an overall rate of 2.7% adverse events per injection, 7.0% per joint, and 8.3% per patient. No systemic adverse events were noted in any patient. The adverse events were characterized by pain and/or transient swelling of the injected joint, mostly mild or moderate in intensity, and 72% of the adverse events were considered to be possibly or probably related to the injection. The incidence of adverse events is significantly influenced by the injection technique: 5.2% adverse events per injection with a medial approach to a partially bent knee, and 2.4% (straight medial) and 1.5% (straight lateral). After an adverse event, clinical improvement still occurred in 69% of the affected knees.

CONCLUSION

Hylan G-F 20 provided good clinical benefits and an acceptable safety profile in current clinical practice. The occurrence of adverse events after an intraarticular hylan injection is infrequent and unpredictable and is not necessarily hylan related, although injection related.

Evaluation of intraocular pressure with Healon and Healon GV in sutureless cataract surgery with foldable lens implantation

PURPOSE

To evaluate transient increases in intraocular pressure (IOP) after use of high-viscosity viscoelastic agents in cataract surgery.

SETTING

Military Hospital, Ulm, Germany.

METHODS

In a prospective, randomized study, we evaluated IOP following cataract surgery using two different viscoelastic substances (Healon, Healon GV). The viscosity of Healon GV is 10 times higher than that of Healon because of higher concentration and molecular weight. Patients having identical phacoemulsification procedures (sutureless clear corneal tunnel incision with foldable silicone lens implantation) (N = 60) and identical viscoelastic removal were assigned to groups of 15 based on viscoelastic used and removal time (20 or 40 seconds). Intraocular pressure was measured preoperatively and at 6, 24, 36, and 48 hours and 1 month postoperatively.

RESULTS

The highest mean IOP elevations in both viscoelastic groups were obtained at 24 hours postoperatively (2.9 mm Hg +/- 4.3 [SD] with Healon and 3.3 +/- 6.3 mm Hg with Healon GV). There were no statistically significant differences between the two viscoelastics and the two removal times during the entire follow-up period (unpaired t-test), but standard deviations were higher in the Healon GV groups at 6 and 24 hours. Two patients in the Healon groups and three in the Healon GV groups required medical treatment for IOP within the first 24 postoperative hours; however, all five patients had an IOP lower than 22 mm Hg on the second postoperative day.

CONCLUSIONS

Based on postoperative IOP, both viscoelastics can be equally well removed from the anterior chamber. Incidence of high IOP using high-viscosity hyaluronic acid is minimized by the described removal technique.

Anesthesia and preoperative and postoperative medications

Although certain methods such as retrobulbar blocks are used extensively, improvements in procedure can always be implemented. The use of ultrasound, low concentrations of anesthesia, careful monitoring, and, in the case of risk patients, anesthesia standby are all important considerations to ensure uneventful treatments. Topical anesthesia eliminates needle risk as well as risk of ptosis and bruising. Because it has been demonstrated that bacteria routinely enter the anterior chamber during uncomplicated cataract surgery, certain irrigation solutions are helpful, but still debatable. Postoperatively, diclofenac, flurbiprofen, and timolol have all been proven to be effective in reducing ocular inflammation, reducing incidence of CME, and controlling pressure increase, respectively.

Healon GV versus Healon in demanding cataract surgery

This study compared how well two sodium hyaluronate viscoelastics maintained the anterior chamber during cataract surgery in eyes at risk for high vitreous pressure. Patients were divided into two groups based on the sodium hyaluronate used: Healon or Healon GV. Qualitative data were obtained with a digital slide gauge attached to the operating microscope. After capsulorhexis, mean anterior chamber depth (distance of the corneal apex to the iris plane) was significantly greater in the Healon GV group (P = .0012). Subjective intraoperative evaluation by surgeons also favored Healon GV. There was no difference between the groups in postoperative inflammation, corneal edema, intraocular pressure, or visual acuity. Therefore, although the two viscoelastics are equally safe, Healon GV maintains the anterior chamber better during cataract surgery.

Effect of sodium hyaluronate ophthalmic solution on peripheral staining of rigid contact lens wearers

We evaluated the efficacy of sodium hyaluronate ophthalmic solutions on 3 and 9 o'clock staining with rigid contact lens wearers in a double masked multicenter study involving four institutions and 43 patients. Both sodium hyaluronate (0.1%) and control ophthalmic solutions (artificial tears) without preservative were used. Patients were randomly divided into two groups. The test group received sodium hyaluronate ophthalmic solution, and the control group received artificial tears as a control ophthalmic solution. The agents were instilled six times per day for 2 weeks while patients wore contact lenses. Although subjective symptoms improved similarly in the two groups, slit lamp observation, corneal staining, and anterior segment photography demonstrated improved results in eyes having received sodium hyaluronate ophthalmic solutions. We conclude that sodium hyaluronate ophthalmic solution is effective and safe for treating 3 and 9 o'clock staining in rigid contact lens wearers.

Clinical evaluation of high-molecular-weight sodium hyaluronate for the treatment of patients with periarthritis of the shoulder

The clinical efficacy and tolerability of sodium hyaluronate, a high-molecular-weight hyaluronic acid preparation, in the treatment of patients with periarthritis of the shoulder was investigated in a multicenter, cooperative study. Of 70 patients seen at 12 participating centers between April and September 1992, follow-up was possible in 62 (28 men and 34 women; mean age, 65.4 years). Patients received sodium hyaluronate 25 mg (1% solution in an ampule) once weekly for 5 weeks by injection into the glenoid cavity or the subacromial bursa. If periarthritis resolved during this period, treatment was stopped; if periarthritis had not fully resolved by the end of the 5 weeks, weekly or biweekly treatment was continued as appropriate. The mean treatment period was 8.16 +/- 0.88 weeks, and the mean total administered dose was 6.05 +/- 0.61 ampules. Rates of improvement over pretreatment values were 75.0% for pain at rest, 73.7% for pain on motion, and 78.8% for pain on pressure. Significant increases in joint angles (measured as components of joint range of motion after administration of sodium hyaluronate) were observed; activities of daily living also improved significantly (P < 0.05 to P < 0.001). No adverse reactions were observed. These results strongly suggest that sodium hyaluronate is an effective agent for the treatment of patients with periarthritis of the shoulder.

Clinical comparison of Provisc and Healon in cataract surgery

This prospective, randomized, multicenter clinical trial compared the safety and efficacy of the Provisc and Healon viscoelastics. Sixty-one eyes of 61 patients had an extracapsular cataract extraction with implantation of a posterior chamber intraocular lens with the aid of Provisc (n = 32) or Healon (n = 29). Mean changes in preoperative versus postoperative corneal thickness and intraocular pressure and the incidence and magnitude of postoperative corneal edema and iritis were not significantly different between the two groups. Observed complications were considered consequences of the surgery and unrelated to viscoelastic use. No adverse medical events occurred. These results indicate Provisc and Healon are clinically equivalent in terms of safety and efficacy when used as surgical aids.

Acute local reactions after intraarticular hylan for osteoarthritis of the knee

OBJECTIVE

To describe acute local reactions following intraarticular hylan injection and determine their frequency.

METHODS

Retrospective review of all patients with osteoarthritis of the knee treated with hylan by 3 rheumatologists.

RESULTS

Twenty-two patients had 88 injections to 28 knees. Six patients had reactions within 24 h of injection characterized by pain, warmth, and swelling, lasting up to 3 weeks. This occurrence was unpredictable. Corticosteroid injections were sometimes required. Synovial fluid cell counts were 5.0-75.0 x 10(9)/l, often with a prominent mononuclear component. Crystal studies and cultures were negative. Radiographic chondrocalcinosis was present in only 1 patient. One patient had serum antibodies to chicken serum proteins.

CONCLUSION

Intraarticular hylan was associated with significant local inflammatory reactions in 27% of patients, or 11% of injections. The mechanism(s) and long term sequelae are unclear.

[Postoperative intraocular pressure in the first days after intraocular administration of hyaluronic acid solution with different viscosities]

BACKGROUND

Viscoelastic substances are used in anterior segment surgery to reduce tissue trauma and endothelial cell loss and to serve as space maintainer. Healon GV (approximately greater viscosity), a hyaluronic acid product with a ten times higher viscosity than Healon, is utilized in complicated procedures (vitreous pressure, flat anterior chamber, congenital cataracts, etc.) and often in phacoemulsification. Intraocular pressure (IOP) rise following incomplete removal is a known problem.

MATERIALS AND METHODS

A prospective randomized study was performed to evaluate the IOP following cataract surgery with Healon or Healon GV and different removal times (RT). Forty patients (forty eyes) having uncomplicated phacoemulsification with foldable silicone posterior chamber lens implantation and identical viscoelastic removal technique were assigned to four groups: Healon with 20 or 40 seconds (sec.) RT, Healon GV with 20 or 40 sec. RT. All surgeries were performed by the same surgeon using the same technique especially for the removal of the viscoelastic. All patients had an identical pre- and postoperative medication. Intraocular pressures were obtained using Goldman's applanation tonometry preoperatively, six, 24, 36, and 48 hours postoperatively.

RESULTS

The IOP follow-up showed no significant difference between the two viscoelastic substances and the two different removal times of 20 and 40 sec. (t-test). In four patients (two of the Healon-groups, two of the Healon GV-groups) the IOP required treatment. On the second postoperative day, the same four patients showed IOP lower than 22 mm Hg. The highest mean-IOP (mm Hg) in both Healon-groups was obtained at 24 hours postoperatively: 18.5 +/- 3.9 SD (Healon); 17.3 +/- 5.9 SD (Healon GV).

CONCLUSION

The incidence of postoperative rise in IOP using high viscosity hyaluronic acid (Healon GV) can be minimized by the applied removal technique. Both viscoelastics-despite of higher molecular weight and viscosity-can be removed equally from the anterior chamber following phacoemulsification and posterior chamber lens implantation utilizing IOP as a parameter in vivo.

Viscoelastic-related glaucomas

The routine surgical use of viscoelastic substances has revolutionized many anterior segment procedures. All of the currently available agents may be responsible for causing or exacerbating a transient, but occasionally significant, postoperative IOP elevation. In spite of differences in physical properties such as molecular weight, concentration, and viscosity, none of the various viscoelastics has consistently shown a decreased likelihood of producing ocular hypertension. Moreover, any newly introduced product must be evaluated carefully for this potential complication. Lavage of viscomaterial from the anterior chamber and administration of ocular antihypertensives may be helpful in averting or controlling the increased IOP. The surgeon should be cognizant of any pre-existing optic nerve damage and adjust the aggressiveness of postoperative glaucoma therapy accordingly. In the future, the development of new substances or simultaneous use of degrading enzymes may reduce or eliminate the incidence of viscoelastic-induced ocular hypertension.

A double-blind, randomized study of Healon GV compared with Healon in penetrating keratoplasty

A double-blind, parallel, randomized study was conducted to compare the efficacy of Healon GV versus Healon in penetrating keratoplasty (PK). Its objective was to investigate whether Healon GV maintains space in the open anterior chamber better than Healon does during removal of the corneal button. Excluding those patients with an anterior chamber lens implant or a known history of glaucoma, 35 patients scheduled for PK entered the study. After penetration of the cornea with the trephine, a specific amount (0.2 ml) of Healon GV or Healon was injected into the anterior chamber. The corneal button was removed and the distance (mm) between iris and cornea (epithelial side) was measured with a digital slide gauge mounted between the permanent and mobile stand of the microscope. A significant difference between the two groups was shown in the measurements of the distance between the iris and the outer side of the cornea. The mean distance for Healon GV was 1.5 +/- 0.6 mm and for Healon it was 1.1 +/- 0.4 mm (p = 0.038). The removal of the corneal button was significantly facilitated when Healon GV was used (p = 0.021). In conclusion, Healon GV was found to be superior in the ability to maintain space in the open anterior chamber.

Intra-articular injections of 750 kD hyaluronan in the treatment of osteoarthritis: a randomised single centre double-blind placebo-controlled trial of 91 patients demonstrating lack of efficacy

OBJECTIVE

To determine the safety and efficacy of intra-articular injections of hyaluronan in the treatment of osteoarthritis of the knee.

METHODS

A randomised double-blind placebo-controlled trial was carried out on 91 patients with radiologically confirmed osteoarthritis of the knee who were recruited from the outpatient clinics.

RESULTS

It was found that weekly intraarticular injections of 20 mg of hyaluronan of M(r) = 750,000 (Hyalgan) in 2 ml of buffered saline performed no better than the inert vehicle alone over a five week period. The principal side effects of a transient increase in pain and swelling in the affected knee was observed in 47% of the treatment group compared with 22% of the placebo group. A few patients with radiologically mild disease treated with Hyalgan appeared to experience medium to long-term symptomatic improvement over matched placebo controls as judged by a delayed return to previous NSAID therapy or analgesia other than paracetamol. Patient numbers in the survival groups, however, were too small to be meaningful.

CONCLUSION

It is concluded that intraarticular administration of this preparation of 750 kD hyaluronan offers no significant benefit over placebo during a five week treatment period, but incurs a significantly higher morbidity, and therefore has no place in the routine treatment of osteoarthritis.

Crystallization on intraocular lens surfaces associated with the use of Healon GV

OBJECTIVE

To describe a series of patients who had visually significant crystalline deposits on their intraocular lenses during cataract surgery with the use of Healon GV (a high concentration and high molecular-weight hyaluronate sodium).

METHODS

Patients were examined for crystalline deposits on their intraocular lenses. These deposits were compared with intraocular lens type, viscoelastic solutions, any other intraocular substance used, type of surgery, and perioperative medications.

RESULTS

In the 11 patients with documented changes (six photographically), the only consistent finding was the use of Healon GV. Furthermore, since we discontinued the use of Healon GV, we have not seen a recurrence of these deposits in more than 500 consecutive patients. The deposits could last a long time (at least 6 months) if sequestered by the posterior capsule, and they are believed to be visually significant at times (Snellen visual acuity of 20/40 or worse).

CONCLUSION

Healon GV use is associated with a new clinical finding of crystalline deposits on intraocular lenses. These deposits can be clinically significant.

Effect of timolol vs. acetazolamide on sodium hyaluronate-induced rise in intraocular pressure after cataract surgery

This prospective study was done to compare the efficacy of timolol and acetazolamide in lowering the intraocular pressure (IOP) secondary to the use of sodium hyaluronate (Healon) in cataract surgery. Fifty patients undergoing extracapsular cataract extraction and implantation of a posterior chamber lens were randomly assigned to one of four treatment groups: no viscoelastic (10 patients), Healon with 0.5% timolol drops postoperatively (12 patients), Healon with acetazolamide postoperatively (16 patients), or Healon only (12 patients). The IOP was measured during the first 24 hours after surgery. Sodium hyaluronate caused a marked increase in IOP in the early (6 to 12 hours) postoperative period. Timolol proved to be more effective than acetazolamide in controlling this pressure increase.

[Low molecular weight heparin inhibits raised intraocular pressure following intracameral administration of sodium hyaluronate]

The effect of low molecular weight (LMW) heparin on increase of intraocular pressure following intracameral administration of sodium hyaluronate (HA) was investigated in rabbit eyes. In each case, the aqueous humor of one eye was replaced with HA and a balanced salt solution (BSS) containing 10.0 IU/ml of LMW heparin, and as a control the aqueous humor of the fellow eye was replaced with HA and BSS containing no LMW heparin. Intraocular pressure was measured for 24 hours following the replacement. As a result, significant increase of intraocular pressure was observed at 6 hours after the injection in the eyes administered HA and BSS. In comparison, no significant increase of intraocular pressure was observed in the eyes injected with HA and LMW heparin. When the concentration of LMW heparin was less than 2 IU/nl or the LMW heparin was heat-deactivated, the HA-induced increase of intraocular pressure was not inhibited. The results indicated that LMW heparin inhibits increase of intraocular pressure following intracameral administration of HA possibly by an inhibitory effect on intraocular fibrin exudation, and the increase of intraocular pressure is probably associated with interaction between fibrin and HA.

Intraarticular injections of hyaluronan in patients with cartilage abnormalities and knee pain. A one-year double-blind, placebo-controlled study

OBJECTIVE

To compare the effect of intraarticular injections of hyaluronan and placebo (vehicle, saline) in patients with knee pain on exertion and with joint cartilage abnormalities.

METHODS

Fifty-two patients with arthroscopically verified deep cartilage fissures and villus-like flakes in the symptomatic knee were randomly assigned to receive intraarticular injections of 2.5 ml of either hyaluronan or vehicle, weekly for 5 weeks. The effect was evaluated by both primary and secondary parameters of efficacy at 2, 4, 13, 26, and 52 weeks.

RESULTS

At the followup visits, both groups had improvement from baseline; however, there was no difference between the groups in any of the relevant variables at any time point.

CONCLUSION

The effects of intraarticular hyaluronan do not differ significantly from those of placebo in patients with knee pain and cartilage disease.

Stripping of Descemet's membrane: a clinicopathologic correlation

We describe a case of accidental injection of sodium hyaluronate (Healon) anterior to Descemet's membrane that caused the membrane to become almost completely detached. The patient eventually underwent penetrating keratoplasty, permitting histopathologic study of the detachment. Sodium hyaluronate globules in the space between the posterior stroma and Descemet's membrane were demonstrated by light and electron microscopy. In addition, 111 consecutive cases of Descemet's membrane detachment identified pathologically were reviewed to identify potential predisposing risk factors and determine corneal pathologic changes. A history of previous intraocular surgery was present in 89 (80%) of the cases; cataract surgery, the most common, had occurred in 52 (58%). Frequent associated corneal pathologic findings were bullous keratopathy in 48 (43%) of the specimens, and scarring and vascularization in 33 (29.7%). In one case that was identified and studied histopathologically, a 90% detachment of Descemet's membrane was noted clinically following the reformation of the anterior chamber with sodium hyaluronate. We conclude that in the cases of Descemet's membrane detachment that came to pathologic examination, intraocular surgery was a major predisposing risk factor. Corneal pathologic changes, which were common, possibly masked the clinical diagnosis of Descemet's membrane detachment in some cases.

Phacoemulsification with aspirated or retained Viscoat

Endothelial cell counts, morphology, and 24-hour postoperative intraocular pressure (IOP) changes were measured in 55 consecutive patients (60 eyes) who had uncomplicated phacoemulsification and posterior chamber lens implantation with either aspirated (30 eyes) or retained (30 eyes) Viscoat (sodium chondroitin sulfate-sodium hyaluronate). The surgical technique was standardized in all cases. Endothelial cell loss was almost identical in the aspirated and in the retained groups (8.8% and 8.7%). Postoperative pleomorphism was significantly less in the retained Viscoat group than in the aspirated group, suggesting a possible protective effect of the retained viscoelastic. Corneal thickness increased significantly in the retained Viscoat group, but this was not significant clinically. The retained Viscoat group had more patients with a postoperative IOP greater than 30 mm Hg and a greater mean increase in postoperative IOP, although the difference between the groups was not significant. The IOP changes may have been caused by blockage of the trabecular meshwork by the retained Viscoat. The results suggest that Viscoat can be retained after cataract surgery if the surgeon is prepared for a greater 24-hour postoperative increase in IOP.

The influence of the incision length on the early postoperative intraocular pressure following cataract surgery

In a prospective study we recorded the early postoperative intraocular pressure of 60 eyes following phacoemulsification and posterior chamber lens implantation. In 30 patients each the implantation either of a folded polyHema intraocular lens through a 3.5 mm incision or of a polymethylmetacrylate intraocular lens through a 7 mm incision was performed. Healon was used in all eyes and thoroughly evacuated from the capsular bag behind the implanted lens and the anterior chamber. For intraoperative miosis 0.5 ml acetylcholine chloride was injected into the anterior chamber after wound closure. Intraocular pressure was measured preoperatively as well as six hours, 18 hours, one week and two months postoperatively without the influence of antiglaucomatous medication. We found no statistically significant change of intraocular pressure at any measurement time in the 3.5 mm group (Student's t-test, p > 0.1). In the 7 mm group only the rise of intraocular pressure at 18 hours was statistically significant (p < 0.05, student's t-test). The comparison of the changes of intraocular pressure from preoperative values between both groups revealed a statistically significant difference at 18 hours (p < 0.05, student's t-test) but not at any other time recorded. Intraocular pressure exceeding 22 mmHg was found at 6 hours in 4 (13.3%) patients of both groups and at 18 hours in 3 (10%) eyes of the 3.5 mm group and 5 (16%) eyes of the 7 mm group (p > 0.1, Fisher's Exact Test). From these results we conclude that 1) regardless of the wound size the pressure rising effect of Healon is successfully counteracted by the aspiration technique described, and 2) with small-incision cataract surgery statistically significant less changes of intraocular pressure are observed in the early postoperative period.

Viscoelastic substance in the anterior chamber elevates intraocular pressure

An 85-year-old man underwent an extracapsular cataract extraction OD with posterior chamber intraocular lens implantation. Sodium hyaluronate (0.3 mL) was used during the procedure, and approximately 1.0 mL of the solution, including the sodium hyaluronate, was aspirated before wound closure. The next day, the intraocular pressure OD was elevated to 60 mmHg, and it remained high despite medication. Three days later, the intraocular pressure was still high, a paracentesis was done, and viscous solution was obtained. After the paracentesis, the intraocular pressure OD normalized.

Hylan gel biomaterial: dermal and immunologic compatibility

Hylan, a hyaluronan derivative, was chemically cross-linked with divinyl sulfone to produce a water-insoluble gel. This gel was fragmented into a gel slurry and evaluated for particle size, biocompatibility, and residence times in selected tissues. Hylan gels used in this study are made up of pseudoplastic, deformable gel particles with greater elasticity (at all frequencies) and greater viscosity (shear rates, 0.01 sec-1) than the water soluble hylan polymer. Hylan gel was injected intradermally and subdermally in mice and was found to produce a minimal reaction at 24 h; thereafter (up to 7 weeks) there was no significant tissue reaction. Intradermal injection of [3H]-hylan gel in guinea pigs revealed a minimal tissue reaction after 1 week, and measurement of radioactivity in the tissue at 1, 2, and 4 weeks revealed only a slight decrease in the total amount of injected radioactivity. The immunogenic activity of hylan gel was evaluated in rabbits; unmodified hylan gel, degraded hylan gel, and hylan gel ovalbumin conjugate were used to immunize rabbits. No antibody production to any hylan gel sample was detected, although control rabbits immunized with ovalbumin developed titers > 400 of antiovalbumin antibodies by day 21, as measured by the passive cutaneous anaphylaxis assay (PCA). Last, serum from owl monkeys (Aotus trivirgatus) in which hylan gel had been placed intravitreally for up to 3 years contained no detectable anti-hylan gel antibodies (PCA assay). Skin tests on these monkeys were also negative.

An analysis of clinical studies of the use of crosslinked hyaluronan, hylan, in the treatment of osteoarthritis

Viscosupplementation with hyaluronan is a safe modality for treating osteoarthritis (OA) of the knee, but it often requires many injections to achieve efficacy. This may result from insufficient elastoviscous properties of current hyaluronan preparations or too rapid egress from the joint. Because both of these properties would be improved by increasing the molecular weight of the substance, hylans, or crosslinked hyaluronans, were developed as therapeutic agents for viscosupplementation of osteoarthritic synovial fluid. This report reviews the results of 4 clinical trials in Germany that assessed the efficacy and safety of hylan G-F 20 (Synvisc).

Intra-articular treatment with hyaluronic acid in osteoarthritis of the knee joint: a controlled clinical trial versus mucopolysaccharide polysulfuric acid ester

In a single-blind, randomized clinical trial, both the efficacy and safety of hyaluronic acid (HA) were compared with that of mucopolysaccharide polysulfuric acid ester (MPA) in patients with osteoarthritis of the knee joint. Both agents were administered intra-articularly over six weeks. Patients received either seven injections of HA or 13 injections of MPA. Joint function, range of motion, severity of pain, the general condition of the bony structure and soft tissue of the joint area, and the global clinical efficacy and safety of the medication were assessed. The mean improvement in the modified total Larson rating score was 22% (SD = 28) after HA treatment and 7% (SD = 17) after treatment with MPA (analysis of variance: p = 0.02). This change was mainly caused by a reduction of pain. The onset of pain relief was more rapid in the HA group. The therapeutic effect increased in both treatment groups during the follow-up period. During this interval, lasting six months after the start of treatment, a further reduction of pain and an improvement of knee joint function could be observed. At the end of the study, 25 out of 33 (76%) patients in the HA group and 11 out of 24 (46%) patients in the MPA group were symptom-free or markedly improved (Chi-square test: p = 0.02). Both agents were tolerated very well.

Use of sodium hyaluronate in treating temporomandibular joint disorders: a randomized, double-blind, placebo-controlled clinical trial

This study assessed the efficacy of high-molecular-weight sodium hyaluronate as a treatment for certain intracapsular temporomandibular joint (TMJ) disorders. One hundred twenty-one patients were studied at three test sites using a randomized, double-blind, placebo-controlled experimental design. Patients were selected on the basis of 1) confirmed diagnosis of either degenerative joint disease (DJD), reducing displaced disc (DDR), or nonreducing displaced disc (DDN); 2) nonresponsiveness to nonsurgical therapies; and 3) severe dysfunction as established by the Helkimo indices (HI), visual analog scales (VASs), and physical measurements of joint movement and joint noise (arthrophonometry [APM]). Subjects received a unilateral upper joint space injection of either 1) 1% sodium hyaluronate in physiologic saline (MedChem Products, Woburn, MA) or 2) USP physiologic saline. Clinical evaluations were performed using HI, VAS, and APM at weekly intervals for the first month and then at monthly intervals up to 6 months postinjection. Statistical analyses for both categorical and continuous variables were performed for each diagnostic category at each examination interval. For DJD, no difference in outcome was seen between treatment groups. For DDN, significant between-group differences were seen through 1 month; however, beyond this time point, the number of DDN patients was insufficient to draw meaningful conclusions concerning efficacy. For DDR, statistically significant within-group and between-group improvement in all three measures (HI, VAS, APM) was seen for the hyaluronate group compared to the saline group throughout the 6-month test period. At the month-2 and month-3 examination intervals, twice as many patients treated with hyaluronate (90%) showed improvement compared to patients given placebo. Further, only 3% of patients with DDR who were treated with hyaluronate relapsed compared with 31% of patients with DDR given placebo.

[The use of domestic viscoelastic substances in IOL implantation and their toxicity to endothelial cells in vitro]

34 senile cataract patients were randomly divided into groups of 1% sodium hyaluronate (Healon) 14 patients, 2% hydroxypropylmethylcellulose (HPMC) 10 patients and Viscose 10 patients for extracapsular cataract extraction with IOL implantation. The rate of endothelial cell loss, the corneal thickness, the intraocular pressure, and the anterior chamber reactions were investigated; the toxicity of the viscoelastic substances on human corneal endothelial cells was studied in vitro for comparative evaluation.

Effect of acetylcholine on intraocular pressure following small-incision cataract surgery

40 patients, who underwent phacoemulsification and implantation of a polyHema intraocular lens (IOGEL-1103) were assigned to two groups. After evacuation of Healon from the capsular bag behind the lens and the anterior chamber, either 0.5 ml of 1% acetylcholine chloride or 0.5 ml of balanced salt solution was injected into the anterior chamber. When compared with preoperative values, the mean intraocular pressure (IOP) 6 h postoperatively was unchanged in the acetylcholine group (0 +/- 8.5 mm Hg) but increased in the control group (+4.1 +/- 7.4 mm Hg). 18 h postoperatively, the mean intraocular pressure slightly decreased in the acetylcholine group (-0.5 +/- 6.1 mm Hg) compared with an increase of +1.4 +/- 4.4 mm Hg in the control group. Intraocular pressure exceeding 25 mm Hg was observed at 6 h in 2 (10%) patients of the acetylcholine group and in 4 (20%) of the control group. At 18 h, intraocular pressure was elevated in only 1 (5%) patient of the acetylcholine group and in 3 (15%) of the control group. From these results, we conclude that the evacuation of Healon from the capsular bag behind the implanted lens and acetylcholine reduce the incidence of postoperative elevations of intraocular pressure.

Hyaluronan applied to lesioned round window membrane is free from cochlear ototoxicity

Hyaluronan (HYA) in 1% solution was instilled into the round window (RW) niche of rats (n = 6) prior to perforating the round window membrane (RWM). Cochlear functioning and structure were then monitored by recording auditory brainstem responses (ABRs) at 2-31.5 kHz and by scanning electron microscopy. Perforation of the RWM alone (n = 6) resulted in immediate loss of ABR thresholds between 6 and 31.5 kHz in 2 of 6 animals. Similar results were obtained after instilling HYA into the RW niche and subsequent RWM perforation (n = 6). After 2 months, ABR thresholds were recorded at all frequencies in the HYA-treated animals, whereas in 2 of the controls no ABR thresholds could be elicited at 20 and 31.5 kHz. However, in both treatment groups the mean ABR thresholds and mean latencies for wave II at the ABR threshold returned to the pre-surgical (normal) range after 2 months. With respect to the cochlear morphology the results in both treatment groups were also alike including minor structural changes in hair cell stereociliae but no loss of hair cells. It is concluded that HYA, when instilled into the middle ear with the inner ear opened, is free from cochlear otoxicity.

Sodium hyaluronate application to the open inner ear: an ultrastructural investigation

The effect of 1 percent sodium hyaluronate on the open inner ear was tested in a series of guinea pigs. By removing the stapes footplate from its original position in the oval window, direct access to the vestibule from the inner ear was achieved. The oval window niche was filled with either 1 percent sodium hyaluronate or 0.9 percent NaCl. The animals were examined with regard to both the cochlear and the vestibular partitions of the inner ear. No marked differences could be seen between the test group and the controls. Thus the organ of Corti as well as the vestibular end organs presented with normal anatomy throughout. Neither did the behavior of the animals in any way indicate any signs of inner ear disturbance. It is concluded that 1 percent sodium hyaluronate does not seem to harm the inner ear sensory structures even in the case of direct access to the vestibule as can be foreseen if the compound is used during stapes surgery.

Effect of sodium hyaluronate on immediate postoperative intraocular pressure after extracapsular cataract extraction and IOL implantation

We studied 129 eyes which were undergoing extracapsular cataract extraction with IOL-implantation. The amount of residual Healon had a clearcut effect on the IOP elevations postoperatively. In eyes operated on with the intercapsular techniques, pressure elevations and the mean values during the first 6 postoperative hours were significantly higher than in eyes operated on with the planned ECCE (can opener-technique) (P less than 0.01). The pressure elevation reached the maximal values 8-12 h postoperatively and had normalized already at 24 h in most cases, except in glaucomatous eyes which at that time had significantly higher mean IOP values than the non-glaucomatous eyes (P less than 0.01). When operations were done with an air bubble no clearcut postoperative pressure increases could be observed. Our study indicates that a comparatively small amount of Healon may cause a pressure elevation and the amount left in the eye has a greater effect upon the level of the pressure than the duration of the pressure elevation. The less we inject Healon into the eye and the more we avoid leaving it there, the less risk we have of the possibility of vision deteriorating high postoperative intraocular pressure.

Early intraocular pressure rise after trabeculectomy

Intraocular pressure (IOP) was measured 4 to 6 hours after surgery and on the first postoperative day in 35 eyes of 35 consecutive patients undergoing initial trabeculectomy. In 27 eyes, the anterior chamber was re-formed at the completion of surgery with balanced salt solution, and in eight eyes it was reformed with hyaluronate sodium. A total of six eyes (17%) had an IOP of 40 mm Hg or greater 4 to 6 hours after surgery. Patients who received hyaluronate to maintain the depth of the anterior chamber had a significantly greater chance of experiencing a marked postoperative IOP rise, both at 4 to 6 hours (P = .005) and on the first postoperative day (P = .0038). There was no correlation between the postoperative IOP rise and the patient's age, sex, glaucoma diagnosis, preoperative IOP, use of 5-fluorouracil, or the number of sutures used to close the scleral flap. Hyaluronate may contribute to an early increase in IOP that could result in further visual field loss in eyes with severe glaucomatous damage. We recommend early monitoring of IOP after trabeculectomy and avoiding the routine use of hyaluronate.

Management of detachment of Descemet's membrane caused by injection of hyaluronic acid

We report a case in which, in an attempt to reform a flat anterior chamber, hyaluronic acid inadvertently was injected between Descemet's membrane and the corneal stroma. The surgical repair is described and a way to prevent this complication is recommended.