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Biomedical subjects

Peter M Parten

Publications and source records attributed to Peter M Parten.

5 recordsLinked to original sources
PubMed2004

The inverted pear glenoid: an indicator of significant glenoid bone loss.

PURPOSE: The purpose of this study was to determine the amount of glenoid bone loss required to produce an inverted pear glenoid. TYPE OF STUDY: Two-part anatomic study involving live subjects and cadaveric specimens. METHODS: From June 2000 to April 2002, 53 patients (mean age, 30 +/- 13 years) underwent arthroscopic evaluation and treatment with a diagnosis of anterior instability by the senior author (S.S.B.). Each of these patients underwent a 3-portal diagnostic arthroscopy to determine the morphology of the glenoid. Glenoids were classified as either inverted pear or non-inverted pear glenoids based on the visual appearance. The amount of glenoid bone loss was then quantified arthroscopically using a validated methodology. In addition, 6 fresh-frozen cadaveric specimens (mean age, 74.1 +/- 7.4 years) were dissected and evaluated to determine the minimum amount of bone loss required to produce an inverted pear glenoid. RESULTS: Forty-two patients were classified as having non-inverted pear glenoids and 11 patients were classified as having inverted pear glenoids. The mean amount of bone loss anteriorly was significantly more (P <.000006) in the inverted pear glenoid group (mean, 8.6 mm; range, 6 to 12 mm) than the non-inverted pear glenoid group (mean, 1.5 mm; range, 0 to 3.0 mm). The percentage of loss of glenoid width was also significantly different (inverted pear mean, 36%; range, 25% to 45% versus non-inverted pear mean, 6.2%; range, 0% to 12.5%; P <.000006). The mean amount of bone loss required in cadaveric specimens to convert a normal pear-shaped glenoid into an inverted pear glenoid was 7.5 mm (range, 6.5 to 9.0 mm), representing 28.8% of the glenoid width (range, 27% to 30%). CONCLUSIONS: The results of this study show that the majority of patients with the diagnosis of anterior instability show some bone loss anteriorly. However, the inverted pear glenoid represents a significant amount of bone loss, at least 25% to 27% of the width of the inferior glenoid. In patients with an inverted pear glenoid, a bone grafting procedure to restore the normal articular arc of the glenoid should be strongly considered to re-establish normal stability to the shoulder.

Adult↗
PubMed2004

Surgery about the coracoid: neurovascular structures at risk.

PURPOSE: The purpose of this study was to examine the neurovascular structures at risk when performing surgery about the coracoid. TYPE OF STUDY: Anatomic cadaveric study. METHODS: Five fresh-frozen cadaveric shoulders were dissected to determine the dimensions of the coracoid and the distance from the coracoid to adjacent neurologic and vascular structures. The minimal distance from the coracoid tip to the axillary nerve, musculocutaneous nerve, the lateral cord of the brachial plexus, and the axillary artery was measured using a precision caliper. Similarly, the minimal distance from the base of the coracoid to the axillary nerve, musculocutaneous nerve, the lateral cord of the brachial plexus, and the axillary artery was measured. RESULTS: The coracoid tip was defined as that portion of the bone that was distal to the "elbow" of the coracoid. Results showed that the mean width (medial-to-lateral dimension in the plane of the subscapularis tendon) of the coracoid tip was 15.9 +/- 2.2 mm, and the mean length of the coracoid tip was 22.7 +/- 4.5 mm. The mean thickness of the coracoid tip at its midportion was 10.4 +/- 1.5 mm. The portion of the coracoid tip which was closest to the neurovascular structures was the anteromedial portion of the coracoid tip. The distance from the anteromedial portion of the coracoid tip to the axillary nerve, the musculocutaneous nerve, the lateral cord, and the axillary artery was 30.3 +/- 3.9 mm, 33.0 +/- 6.2 mm, 28.5 +/- 4.4 mm, and 36.8 +/- 6.1 mm, respectively. Similarly, the portion of the base of the coracoid that was closest to the neurovascular structures was its anteromedial portion. The shortest distance from the anteromedial aspect of the base of the coracoid to the axillary nerve, the musculocutaneous nerve, the lateral cord, and the axillary artery was 29.3 +/- 5.6 mm, 36.5 +/- 6.1 mm, 36.6 +/- 6.2 mm, and 42.7 +/- 7.3 mm, respectively. CONCLUSIONS: Procedures about the coracoid are relatively safe procedures. The lateral cord of the brachial plexus is at greatest risk during dissection about the tip of the coracoid, and the axillary nerve is at greatest risk during dissection about the base of the coracoid. The safety of arthroscopic coracoplasty or interval releases is further increased by the fact that most of the work is performed on the lateral aspect of the coracoid, which is even further away from the neurovascular structures. CLINICAL RELEVANCE: This study quantifies the relative risk of injury to neurovascular structures during arthroscopic surgery about the coracoid.

Anthropometry↗
PubMed2003

Combined subcoracoid and subacromial impingement in association with anterosuperior rotator cuff tears: An arthroscopic approach.

PURPOSE: The purpose of this study was to evaluate the surgical outcome of patients with combined subcoracoid and subacromial impingement with associated rotator cuff tears. TYPE OF STUDY: Case series. METHODS: Eight patients with a mean age of 63.6 (+/- 8.9) years were reviewed. All patients had combined subscapularis, supraspinatus, and infraspinatus tears of the rotator cuff with associated subacromial and subcoracoid impingement. All patients were treated with arthroscopic subacromial decompression, subcoracoid decompression, and rotator cuff repair. RESULTS: At a mean follow-up of 8.8 months (range, 6-12 months), all patients were satisfied with the procedure. The mean University of California Los Angeles (UCLA) score increased from 11.0 +/- 2.6 preoperatively to 30.9 +/- 2.9 postoperatively (P <.00001). Preoperatively, all patients were in the poor category by UCLA criteria. Postoperatively, 2 patients had excellent results, 5 patients had good results, and 1 patient had a fair result. All patients had significant reduction in pain postoperatively, with 4 patients showing complete elimination of pain during all activities. No patient complained of pain anteriorly over the coracoid or had positive impingement signs postoperatively. Active forward elevation increased from a mean of 103.1 degrees +/- 46.5 degrees preoperatively to a mean of 155 degrees +/- 18.5 degrees (P <.02). Preoperatively, 4 patients had no active overhead function with positive Napoleon tests. Postoperatively, all showed improvement of the Napoleon test and regained active overhead function. CONCLUSIONS: Arthroscopic treatment of combined subcoracoid and subacromial impingement can lead to good results in this patient population. A high index of suspicion for these combined lesions, along with adequate surgical decompression and rotator cuff repair, is essential in providing pain relief and improved function.

Aged↗
PubMedDate not supplied

Quantifying glenoid bone loss arthroscopically in shoulder instability.

PURPOSE: Our goal was to establish a consistent methodology for quantifying glenoid bone loss by arthroscopic means. TYPE OF STUDY: This study was an anatomic investigation of glenoid structure and its consistent anatomic landmarks as determined by arthroscopic means in live subjects and by direct measurement in fresh-frozen cadaver specimens. METHODS: We arthroscopically evaluated and measured the location of the bare spot of the glenoid in 56 subjects that had no evidence of instability (average age, 40 years). We also measured the exact location of the glenoid bare spot in 10 cadaver shoulders (average age, 76 years). RESULTS: The bare spot of the glenoid was a consistent reference point from which to determine glenoid bone loss because it was located almost exactly at the center of the circle that was defined by the articular margin of the inferior glenoid below the level of the midglenoid notch. The tightly clustered standard deviations of the bare spot measurements in both the live subjects and the cadaver specimens confirmed its consistent location. CONCLUSIONS: The glenoid bare spot can be used as a central reference point to quantify the percentage bone loss of the inferior glenoid. Such objective measurement of glenoid bone loss can be clinically useful to the surgeon in deciding whether bone grafting is necessary to restore stability to the shoulder with a bone-deficient glenoid.

Adolescent↗