Repair of articular cartilage defects with collagen-chondrocyte allografts.

This study was designed to evaluate the potential use of a prototype collagen-chondrocyte allograft in the repair of full-thickness articular cartilage defects. Articular cartilage was harvested from young donor New Zealand White rabbits, enzymatically digested, cultured in monolayer, and passed into a three-dimensional porous type I collagen sponge (American Biomaterials). The composite grafts were incubated for 1 week. (Phase I) Twenty adult NZW rabbits underwent bilateral knee arthrotomies. Three-millimeter full-thickness articular cartilage defects were made in the trochlea of the distal femur. A 4-mm circular punch from the composite cell-seeded grafts was press-fit into the right knee defects. The left knee served as a control (collagen sponge alone or ungrafted defect). Animals were allowed free activity postoperatively and were killed in groups of five at 4, 8, 12, and 24 weeks postoperatively. Defect areas were harvested. Sections were cut at 5-microm thickness and stained with hematoxylin and eosin. The degree as well as quality of healing were assessed and scored with a grading system modified from Salter and O'Driscoll for cartilage repair. (The maximum score was 24 points.) Safranin-O staining as well as polarized light examination of representative sections was undertaken to assess the proteoglycan content and structural characteristics of the repair matrix. (Phase II) An additional 15 NZW rabbits underwent the above procedure but with the addition of fibroblast growth factor (FGF) (100 ng/ml) and insulin (5 microg/ml) to the growth medium of the composite grafts as stimulators of chondrocyte proliferation and proteoglycan synthesis. Control specimens in phase I and II (collagen sponge alone or ungrafted defects) healed with a primarily fibrous or fibrocartilagenous matrix. Defects grafted with cell-seeded collagen sponges demonstrated enhanced healing at all time points examined when compared to controls. There was a strong tendency toward a hyaline appearing matrix with increased Safranin-O staining and birefringence under polarized light more closely resembling the normal native cartilage. Mean histologic score for grafted defects was 18.4 (+/-3.1). Mean scores for collagen sponge alone and ungrafted defects in phase I were 12.7 (+/-4) and 12.7 (+/-3.1) (P<0.01). The addition of FGF and insulin to the growth medium (phase II) resulted in a significantly enhanced repair matrix when compared to the non-FGF-enhanced grafts, with a greater percentage of hyaline appearing tissue at all time points examined (4,8, and 12 weeks). Organization of the chondrocytes was improved at all time points examined as well. Mean histologic score for the FGF-grafted defects was 21.1 (+/-3.0). Mean scores for collagen sponge alone and ungrafted defects in phase II were 14.9 (+/-2.9) and 15.5 (+/-1.9) (p<0.01).

Video-assisted thoracic surgery for the anterior approach to the thoracic spine.

Standard anterior approach to the thoracic spine is by a posterolateral thoracotomy. Because of the morbidity associated with this incision, video-assisted thoracic surgery (VATS) has been used as a less invasive approach for many intrathoracic disease processes. We have applied VATS for anterior access to the thoracic spine. From April 1991 to September 1994, 95 patients underwent thoracic spine procedures using thoracoscopy as the sole method of anterior approach. Procedures performed include discectomy for herniation (n = 57), multilevel discectomy for correction of spinal deformity (27), corpectomy (9), and drainage of intervertebral disc space abscess (2). All levels of the thoracic spine from the T2-T3 level to the T12-L1 interspace were approached. Forty-four procedures were performed through the left side of the chest and 41 through the right. The planned procedure was accomplished by VATS in all but 1 patient who required conversion to an open procedure because of scarring from a previous spine procedure. Mean operative time was 2 hours 24 minutes (range, 45 minutes to 5 hours 10 minutes). Average chest tube duration was 1.4 days, and mean length of stay was 4.82 days (range, 2 to 21 days). Complications included intercostal neuralgia (6), atelectasis (5), excessive epidural blood loss (2,500 mL; 2) and temporary paraparesis in a scoliosis patient related to operative positioning. We conclude that VATS offers a new, less morbid anterior approach to the thoracic spine. Although there is a significant learning period, most procedures requiring an anterior access can be performed safely by this technique. The VATS approach mandates an expanded role for the thoracic surgeon in operative spine disease.

Pain inhibition of shoulder strength in patients with impingement syndrome.

Fourteen patients with Stage II or III impingement syndrome (average age 58 years) were studied. Nine patients had full-thickness rotator cuff tears documented by arthrograms. Patients initially underwent a thorough shoulder examination followed by baseline isokinetic strength testing. Abduction/adduction testing was performed utilizing a Biodex dynamometer. Maximum concentric contractions were performed, and values for peak torque (PT), total work (W), and power (P) were obtained. All patients received a subacromial injection of 5 cc 1% lidocaine plus 5 cc 0.5% bupivacaine (Marcaine). After 5 minutes the testing sequence was repeated. Clinically, patients demonstrated marked improvement following injection. Eighty-six percent reported complete pain relief; the remaining two patients reported only mild discomfort at the extremes of motion. Improvement in functional activity of the affected shoulder was noted by all subjects. On manual muscle testing, 13 of 14 patients (93%) demonstrated increased abduction strength; 11 of 14 (79%) had improvement in external rotation. Mean increases in active forward elevation and external rotation were 36 degrees and 11 degrees, respectively (P < .01). Postinjection isokinetic changes in PT, W, and P for abduction/adduction were dramatic. For abduction, all patients showed significant increases in P (mean 82%), W (mean 90%), and PT (mean 48%) (all P < .05). No significant differences in range of motion testing or strength parameters were noted based on the presence or absence of a rotator cuff tear. For adduction, all patients showed significant increases in P (mean 208%), W (mean 183%), and PT (mean 41%) (all P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Video-assisted thoracoscopic excision of herniated thoracic disc: description of technique and preliminary experience in the first 29 cases.

This study evaluates the technique and results of video-assisted thoracoscopic surgery (VATS) for the treatment of symptomatic thoracic disc herniation. Results were compared with a literature review of open surgical techniques of thoracic disc excision with regard to efficacy, safety, and surgical outcomes. VATS has recently been described for thoracic surgery as having the advantage of decreased postoperative pain and morbidity, faster patient recovery, and shortened intensive care unit (ICU) hospitalization. Twenty-nine consecutive patients underwent VATS for symptomatic thoracic disc herniation. Herniations ranging from T5-6 to T12-L1 were successfully approached by using a three- or four-portal strategy. Postoperative magnetic resonance imaging (MRI) scans were evaluated. Pre- and postoperative Oswestry Disability Questionnaires and Linear Analog Pain Scale data were obtained. Patients were grouped according to presenting symptoms. The minimal follow-up was 1 year (range, 12-24 months). Mean operative time was 175 min for 29 patients. Significant improvement (p < 0.01, paired t test) was recorded in Oswestry Disability Questionnaires and Linear Analog Scale Tests. Of the patients, 75.8% (22) were satisfied, 3.4% (one) unsatisfied, with 20.1% (six) unchanged. Narcotic use was significantly eliminated or reduced. Mean return to work was 5 weeks (private insurance) and 21 weeks (workers compensation). The surgical and postoperative complication rate was 13.8%. VATS appears to be a safe and efficacious method of excising herniated thoracic discs. Follow-up results at 1 year resulted in high patient satisfaction. VATS advantages include decreased length of hospitalization as well as improved patient comfort.

The evaluation of compartmental syndromes using somatosensory evoked potentials in monkeys.

Somatosensory evoked potentials (SEPs) of the median, deep peroneal, and tibial nerves were recorded in experimentally induced compartmental syndromes in nine Macaca mulatta monkeys. A total of 17 trials were performed at the following mean pressure levels: 17, 30, 36, and 40 mm Hg. Evoked potentials were recorded using a four-channel evoked response system. Significant changes in SEP waveforms (greater than 3-millisecond increases in N1 or P1 latencies, or a 50% decrease in wave amplitudes in the presence of normal contralateral waveforms) were seen at pressures as low as 30 mm Hg as early as 45 minutes. Pressures of 35 and 40 mm Hg led to more pronounced abnormalities in SEP waveforms, with marked decreases in wave amplitudes and variability in the time to onset of these changes. Somatosensory evoked potentials are noninvasive, sensitive, and dynamic determinations of nerve function and may have clinical significance in the early detection of nerve dysfunction in compartment syndromes.

The use of adhesives in chondrocyte transplantation surgery: in-vivo studies.

Two commercial adhesive preparations--fibrin glue and mussel adhesive protein (MAP)--were tested in-vivo for their ability to fix a chondrocyte allograft internally. While results for the fibrin, including additional testing for chondro inductive/conductive properties, were at best inconclusive, the results for MAP are highly promising.

The effect of low-level Nd:YAG laser energy on adult articular cartilage in vitro.

Reports of laser energy applied to soft tissues in vitro and in vivo suggest both stimulation and inhibition of specific metabolic processes, depending on the type of laser, the energy density (ED) used, the mode of delivery, and type of tissue studied. An earlier in vitro study of Nd:YAG laser irradiation of articular cartilage indicated stimulation of both matrix and DNA synthesis for 6 days following laser exposure. In vivo reports on the ability of Nd:YAG laser energy to stimulate the healing of partial-thickness cartilage defects are conflicting. In the present study, a noncontact continuous-wave Nd:YAG laser beam of varying EDs was applied to full-thickness adult articular cartilage explants maintained in organ culture; the metabolic processes of chondrocyte DNA synthesis and matrix synthesis were followed over 2 weeks. For both canine and bovine cartilage, low-levels of laser energy (ED 51-127 J/cm2) stimulated matrix synthesis at 6-7 days following laser exposure, with a concomitant decrease in baseline DNA synthesis. By 12-14 days, however, these dose-dependent effects were no longer seen, with no significant differences from control noted for any of the laser energies studied. Histologic analysis of the cartilage explants following laser exposure showed no significant differences in cell number or morphology between sample and control groups; however, a decrease in matrix proteoglycan staining was seen in the highest laser energy group at all time points. These findings indicate that exposure to low-level noncontact Nd:YAG laser energy promotes a significant stimulation of cartilage matrix synthesis. However, a single exposure may not be sufficient to promote a sustained upregulation of cartilage metabolism.(ABSTRACT TRUNCATED AT 250 WORDS)