Subscapularis Splitting Approach Research Articles

Is There a Nerve-free Zone in Which a Subscapularis Split Can Safely be Performed? An Anatomical Study Using Embalmed Specimens.

The subscapularis muscle, which is part of the rotator cuff, is located anterior to the shoulder. In anterior approaches to the shoulder, its supplying nerves are at risk of iatrogenic injury, which may cause postoperative complications. It is unclear whether there is any nerve-free zone in which a subscapularis split can be performed without risking nerve damage. In an anatomical study, we asked: (1) With the arm abducted 60° and externally rotated, what are the median and shortest distances between the entrance point of the subscapular nerves into subscapularis muscle and the myotendinous junction of this muscle? (2) What are those distances in other positions of the shoulder? (3) Did those measurements differ between specimen sexes or sides? In 84 shoulders of 66 embalmed anatomic specimens, the distance from the myotendinous junction of the subscapularis muscle to the entrance points of the subscapular nerves into the subscapularis muscle was measured using an inelastic thread and a millimeter gauge with the arm abducted 60° and rotated externally. In 16 of 84 shoulders, which were selected randomly, after taking the measurements with the arm abducted 60° and rotated externally, arm positions were changed and further measurements were taken with the arm abducted 60° and rotated neutrally, abducted 60° and rotated internally, and abducted 90° and rotated externally. The positions of the entrance points were described with statistical parameters and compared between different sides, sexes, and joint positions. Measurements were verified using eight fresh-frozen shoulders, showing no difference in distances compared with embalmed specimens and confirming reproducibility of measurements. Absolute distances were used to minimize possible distortion when using correlations and for straightforwardness and clinical applicability. The median (range) distance was 43 mm (24 to 64) for the upper subscapular nerve and 38 mm (23 to 59) for the lower subscapular nerve with the arm rotated externally and abducted 60°. In the 16 subsamples, internal rotation decreased the distance to 34 mm (24 to 49) and 31 mm (15 to 43), respectively, and maximal external rotation and 90° of abduction increased it up to 49 mm (30 to 64) and 41 mm (27 to 56). Comparison of left and right sides yielded no difference. Comparison of sexes showed distances for the lower subscapular nerve of 36 mm (23 to 54) in females versus 39 mm (24 to 60) in males. In no specimen did the nerve come closer than 23 mm medial to the myotendinous junction with the arm rotated externally and abducted. Therefore, not exceeding a distance of 20 mm medial to the myotendinous junction with the arm rotated externally seems to provide sufficient protection from nerve injury during surgery. Based on the described zone of 20 mm medial to the myotendinous junction, the risk of nerve injury in a subscapularis split approach can be minimized.

Anterior Shoulder Instability Part II—Latarjet, Remplissage, and Glenoid Bone-Grafting—An International Consensus Statement

The purpose of this study was to establish consensus statements via a modified Delphi process on the Latarjet procedure, remplissage, and glenoid-bone grafting for anterior shoulder instability. A consensus process on the treatment utilizing a modified Delphi technique was conducted, with 65 shoulder surgeons from 14 countries across 5 continents participating. Experts were assigned to one of 9 working groups defined by specific subtopics of interest within anterior shoulder instability. The technical approaches identified in the statements on the Latarjet procedure and glenoid bone-graft were that a subscapularis split approach should be utilized, and that it is unclear whether a capsular repair is routinely required. Furthermore, despite similar indications, glenoid bone-grafting may be preferred over the Latarjet in patients with bone-loss greater than can be treated with a coracoid graft, and in cases of surgeon preference, failed prior Latarjet or glenoid bone-grafting procedure, and epilepsy. In contrast, the primary indications for a remplissage procedure was either an off-track or engaging Hill-Sachs lesion without severe glenoid bone loss. Additionally, in contrast to the bone-block procedure, complications following remplissage are rare, and loss of shoulder external rotation can be minimized by performing the tenodesis via the safe-zone and not over medializing the fixation. Overall, 89% of statements reached unanimous or strong consensus. The statements that reached unanimous consensus were the prognostic factors that are important to consider in those undergoing a glenoid bone-grafting procedure including age, activity level, Hill-Sachs Lesion, extent of glenoid bone-loss, hyperlaxity, prior surgeries, and arthritic changes. Furthermore, there was unanimous agreement that it is unclear whether a capsular repair is routinely required with a glenoid bone graft, but it may be beneficial in some cases. There was no unanimous agreement on any aspect related to the Latarjet procedure or Remplissage. Level V, expert opinion.

Rotator cuff–sparing approaches for glenohumeral joint access: an anatomic feasibility study

The deltopectoral approach for total shoulder arthroplasty can result in subscapularis dysfunction. In addition, glenoid wear is more prevalent posteriorly, a region difficult to access with this approach. We propose a posterior approach for access in total shoulder arthroplasty that uses the internervous interval between the infraspinatus and teres minor. This study compares this internervous posterior approach with other rotator cuff-sparing techniques, namely, the subscapularis-splitting and rotator interval approaches. The 3 approaches were performed on 12 fresh frozen cadavers. The degree of circumferential access to the glenohumeral joint, the force exerted on the rotator cuff, the proximity of neurovascular structures, and the depth of the incisions were measured, and digital photographs of the approaches in different arm positions were analyzed. The posterior approach permits direct linear access to 60% of the humeral and 59% of the glenoid joint circumference compared with 39% and 42% for the subscapularis-splitting approach and 37% and 28% for the rotator interval approach. The mean force of retraction on the rotator cuff was 2.76 (standard deviation [SD], 1.10) N with the posterior approach, 2.72 (SD, 1.22) N with the rotator interval, and 4.75 (SD, 2.56) N with the subscapularis-splitting approach. From the digital photographs and depth measurements, the estimated volumetric access available for instrumentation during surgery was comparable for the 3 approaches. The internervous posterior approach provides greater access to the shoulder joint while minimizing damage to the rotator cuff.

The Subscapularis Splitting Technique

The subscapularis splitting technique has become a very common approach for the open management of shoulder instability, including repair of Bankart lesions, capsular shift procedures, and the increasingly popular Latarjet procedure. It is often used for young athletes, as the attachment and the length of subscapularis are preserved while other open approaches may result in restricted rotation of the shoulder, particularly external rotation. The current literature reports that routine exposure of the axillary nerve is not necessary during anterior stabilization procedures using a subscapularis muscle-splitting approach if proper precautions are taken to protect the nerve. We present a case in which the axillary nerve was fortuitously noted to be coursing in an abnormally lateral position anterior to the subscapularis belly exposing the nerve at risk during subscapularis split. Our case clearly represents an important anatomic variant which must be considered when performing the subscapularis splitting approach, as serious and functional deficits will result if the nerve is irrevocably damaged. Beware the aberrant axillary nerve.

Quantification of the exposure of the glenohumeral joint from the minimally invasive to more invasive subscapularis approach to the anterior shoulder: a cadaveric study

There are multiple techniques to approach the glenohumeral joint. Our purpose was to quantify the average area of the glenohumeral joint exposed with 3 subscapularis approaches and determine the least invasive approach for placement of shoulder resurfacing and total shoulder arthroplasty instruments. Ten forequarter cadaveric specimens were used. Subscapularis approaches were performed sequentially from split, partial tenotomy, and full tenotomy through the deltopectoral approach. Glenohumeral joint digital photographs were analyzed in Image J software (National Institutes of Health, Bethesda, MD, USA). Shoulder resurfacing and total shoulder arthroplasty instruments were placed on the humeral head, and anatomic landmarks were identified. The average area of humeral head visible, from the least to the most invasive approach, was 3.2, 8.1, and 11.0 cm2, respectively. The average area of humeral head visible differed significantly according to the approach. Humeral head area increased 157% when the subscapularis split approach was compared with the partial tenotomy approach and 35% when the partial approach was compared with the full tenotomy approach. The average area of glenoid exposed from least to most invasive approach was 2.0, 2.3, and 2.5 cm2, respectively. No significant difference was found between the average area of the glenoid and the type of approach. Posterior structures were difficult to visualize for the subscapularis split approach. Partial tenotomy of the subscapularis allowed placement of resurfacing in 70% of the specimens and total arthroplasty instruments in 90%. The subscapularis splitting approach allows adequate exposure for glenoid-based procedures, and the subscapularis approaches presented expose the glenohumeral joint in a step-wise manner. Anatomy study, cadaver dissection.

Clinical function and structural integrity of the subscapularis tendon following open shoulder stabilization

Background Acute and chronic subscapularis dysfunction following tendon release during open shoulder stabilization may lead to reduced clinical outcome and patient satisfaction. The present study aimed to assess whether this occurs using a subscapularis splitting technique. Methods We reviewed 42 patients that underwent open shoulder stabilization using a subscapularis splitting approach. Eleven patients had additional procedures such as bone grafts or a posterior labral repair. The minimum follow-up was 2 years. There were 36 male and six female patients. The mean age was 24.3 years (range 15 years to 47 years). Patients were assessed for range of movement, stability, subscapularis muscle function and strength. The Oxford instability and the Rowe score questionnaires were performed. Magnetic resonance imaging (MRI) was used to assess the integrity and quality of subscapularis muscle and tendon. Results Median postoperative Oxford instability score and Rowe scores were 21 and 70, respectively. Two patients (4.8%) had redislocated following re-injury. No patient had signs of subscapularis dysfunction on examination or on MRI. External rotation was reduced by a mean of 15°. Thirty-two patients (80%) returned to their previous level of sport. Conclusions With a subscapularis splitting technique, we found no significant evidence of clinical or radiological dysfunction of the subscapularis musculotendinous unit.

A Subscapularis-Splitting Approach Yields Improved Postoperative Subscapularis Strength Compared with Tenotomy Following Bristow-Latarjet Procedures

A Subscapularis-Splitting Approach Yields Improved Postoperative Subscapularis Strength Compared with Tenotomy Following Bristow-Latarjet Procedures

Subscapularis Function Following the Latarjet Coracoid Transfer for Recurrent Anterior Shoulder Instability

The Latarjet procedure may be performed with both subscapularis splitting and subscapularis transecting approaches. The subscapularis splitting approach may better preserve subscapularis function and anatomy. The goal of this study was to determine the functional status of the subscapularis after the Latarjet procedure with a subscapularis splitting approach using the quantified belly press test. Thirty patients with traumatic anterior shoulder instability were prospectively enrolled in the study. All patients underwent a Latarjet procedure through a subscapularis splitting approach. Both operative and nonoperative extremities were tested preoperatively with a belly press test using an Isobex muscle strength analyzer (Medical Device Solutions AG, Oberburg, Switzerland). Fifteen patients returned for postoperative Isobex belly press testing at a minimum of 6 months. Average patient age was 23.3 years, and average follow-up interval was 13 months. We detected no significant differences in pre- vs postoperative subscapularis strength in the surgical shoulder (decreased by 0.3 kg [95% CI, -1.0 to 1.7 kg; P=.630]). There was no difference in control vs surgical arm at preoperative (control +0.3 kg stronger; 95% CI, -0.8 to 0.1 kg; P=.124) vs postoperative (control +0.3 kg stronger; 95% CI, -1.1 to 0.5 kg; P=.444) measurements. Neither sex (P=.593) nor surgery in the dominant arm (P=.459) had an effect on recovery of subscapularis strength. Finally, the surgical arm at follow-up was not significantly different from reported height- and weight-based normative values for either men (P=.481) or women (P=.298). This study suggests that subscapularis strength is not significantly altered by the Latarjet procedure with a subscapularis splitting approach.

Recovery of shoulder strength and proprioception after open surgery for recurrent anterior instability: A comparison of two surgical techniques

Previous studies have documented a decrease in proprioceptive capacity in the unstable shoulder. The degree to which surgical approach affects recovery of strength and proprioception is unknown. The recovery of strength and proprioception after open surgery for recurrent anterior glenohumeral instability was compared for 2 surgical procedures. A prospective analysis of 55 consecutive patients with posttraumatic unilateral recurrent anterior glenohumeral instability was performed. Thirty patients (group 1) underwent an open inferior capsular shift with detachment of the subscapularis, and 25 (group 2) underwent an anterior capsulolabral reconstruction. Mean preoperative proprioception and strength values were significantly lower for the affected shoulders in both groups. At 6 months after surgery, there were no significant differences for mean strength and proprioception values between the unaffected and operative sides for group 2 patients. In group 1 patients, however, there were still significant deficits in mean position sense and strength values. Complete restoration of proprioception and strength, however, was evident by 12 months in group 1. This study demonstrates that there are significant deficits in both strength and proprioception in patients with posttraumatic, recurrent anterior glenohumeral instability. Although both are completely restored by 1 year after surgery, a subscapularis-splitting approach allows for complete recovery of strength and position sense as early as 6 months postoperatively. Detachment of the subscapularis delays recovery of strength and position sense for up to 12 months after surgery.

Bristow-Latarjet procedure with specific instrumentation: study of 34 cases

A Bristow-Latarjet procedure with specific instrumentation was performed for recurrent dislocation or subluxation of the glenohumeral joint in 34 patients. The procedure was performed through a subscapularis splitting approach with three specific instruments and a special screw. The clinical outcome was assessed by the Duplay and the Constant scores. Radiographic study was conducted on 23 patients and CT scan in 11 patients. Of the 27 patients interviewed 92% were satisfied. Of the 23 patients examined, 15 had an excellent Duplay score, four a good score, three a medium score, and only one had a bad score. One patient had subluxation episodes, and one patient was revised after a redislocation following violent trauma. On the standard radiographs, all bone blocks were in the correct position. A pseudarthrosis was diagnosed in the patient with subluxation episodes. This device simplifies the surgical technique and provides reproducibility to the procedure.

Shoulder Strength after Open versus Arthroscopic Stabilization

Background With current techniques, the main difference between arthroscopic and open shoulder stabilization is the violation of the subscapularis tendon. No studies have looked at strength differences of internal and external rotation between these groups. Hypothesis Internal rotation strength deficits will exist in patients having undergone an open shoulder stabilization procedure compared with an arthroscopic one. Study Design Piggy-back randomized controlled trial; Level of evidence, 1. Methods Forty-eight patients (38 men, 10 women), average age, 30.6 years (range, 18–59 years), were randomized to either open (n = 24) or arthroscopic (n = 24) shoulder stabilization. Rehabilitation protocols were standardized. At a mean follow-up of 19.4 months (range, 12–36 months) from surgery, patients underwent isokinetic strength testing (concentric and eccentric peak moments at 60 deg/s and 180 deg/s). Measurements were body-mass normalized. Primary outcome was internal rotation strength at 60 deg/s. Results There were no significant differences between groups with respect to age, gender, or operative limb. There were no statistical differences between operative groups for the primary outcome of internal concentric strength at 60 deg/s (mean difference, 0.011 N·m/kg; 95% confidence interval, −0.043 to 0.066; P = .677) or secondary strength measures. When compared with the contralateral limb, strength deficits existed for both surgical groups for both internal and external rotation. Regression analysis demonstrated that arm dominance is a factor in strength deficits. Conclusion The results of this trial suggest there are no side-to-side isokinetic strength deficits between patients having an open stabilization using a subscapularis splitting approach versus arthroscopic stabilization for anterior traumatic shoulder instability at 1 year after surgery. Strength deficits exist in both groups when compared with the contralateral limb.

Proprioception and EMG pattern after capsulolabral reconstruction in shoulder instability: a clinical and experimental study

The anterior capsulolabral reconstruction according to JOBE [13] is a modification of the Bankart operation. The capsular shift is performed via a subscapularis-split approach avoiding any incision into the musculature. A total of 43 patients with posttraumatic, chronic anterior shoulder instability underwent surgery. All patients had at least four dislocations preoperatively. Thirty-five patients were examined after an average of 3.7 +/- 1.4 years. Twenty-nine (82.9%) of these patients were free of pain, with functional assessment showing a mean external rotation deficit of 4.1 degrees +/- 2.9 degrees without any further movement restrictions. On average, a Rowe-Score of 86.1 +/- 12.4 points and an ASES-Score of 93.3 +/- 8.4 were achieved. The reluxation rate was 7.7%. The study demonstrated that despite the good clinical results, only 69% of patients were able to return to their previous sports activity level. This special problem is in agreement with other similar studies [4, 18] so that this relevant fact was further addressed by determination of proprioception and electromyographic muscle activity. Postoperatively, in contrast to other studies [1, 21, 24], a persisting proprioceptive deficit as well as an altered EMG pattern was found together with a significant reduction in activity of the deltoideus muscle on the operated side. These results may explain the problem to achieve complete restitution of the function of the shoulder joint after capsulolabral reconstruction.

Function of subscapularis after surgical treatment for recurrent instability of the shoulder using a bone-block procedure

We compared the long-term function of subscapularis after the Latarjet procedure using two surgical approaches. We treated 102 patients (106 shoulders) with a mean age of 26.8 years (15 to 51) with involuntary unidirectional recurrent instability. The operation was carried out through an L-shaped incision with trans-section of the upper two-thirds of the muscle in 69 cases and with a subscapularis split in 37. All clinical results were assessed by the Rowe and the Duplay scores and the function of subscapularis by evaluating the distance and strength at the lift-off position. Bilateral CT was performed in 77 patients for assessment of fatty degeneration. The mean follow-up was 7.5 years (2 to 15) and 18% of cases were lost to follow-up. The mean Duplay score was 82 of 100 for the L-shaped incision group and 90 of 100 for those with a subscapularis split (p = 0.02). The mean fatty degeneration score was 1.18 after an L-shaped incision compared with 0.12 after subscapularis split (p = 0.001). The subscapularis split approach is therefore recommended.

Sportfähigkeit und Sensomotorik nach Schulterstabilisierung beim Überkopfathleten

The anterior capsulolaboral reconstruction according to Jobe is a modification of the Bankart operation, performing the capsular shift via a subscapularis-split approach avoiding any incision into the musculature. A total of 24 overhead athletes with posttraumatic, chronic anterior shoulder instability underwent surgery. Twenty-two patients were examined after an average follow-up of 2.8 +/- 0.7 years. On average, a Constant-Murley-Score of 93.7 +/- 5.3 points and an ASES-Score of 95.0 +/- 5.1 points were achieved. The relaxation rate was 9 %. The study demonstrated, that despite the good clinical results, only 12 out of 22 (55 %) of patients were able to return to their previous sports activity level. This relevant problem is in agreement with other similar studies so that it was further addressed by determination of proprioception and electromyographic muscle activity. Postoperatively, a persisting proprioceptive deficit as well as an altered EMG pattern was found with a significant reduction in activity of the deltoideus muscle on the operated side. The analysis of the data of each patient showed that there was a significant relation between the restitution of proprioception and ability to return to the previous sports activity level. In contrast, the relation between EMG pattern and full recovery to completely unrestricted shoulder function was not significant.

SHOULDER INJURY LACROSSE

HISTORY A twelve-year-old male presented for surgical correction of instability of his right, dominant shoulder. His first instability episode occurred at the age of 11 years of age when he sustained a hyperabduction injury to his right arm while wrestling. He had recurrent dislocations after that with sports, including lacrosse, football, and diving. His most recent dislocation occurred throwing a frisbee. All of his dislocations required reduction in the emergency room. He thought that the shoulder was dislocating anteriorly He had no history of instability in any of his other joints and was in good health. He had no family history of Ehlers-Danlos syndrome, Marfan's syndrome or other connective tissue disorders. He had no parasthesias, weakness or history of neck pain. PHYSICAL EXAMINATION He was a normal appearing adolescent male with no secondary sex characteristics indicating that he had entered puberty. He had full range of motion of both shoulders and was neurologically intact for light touch, strength testing and reflexes of both upper extremities. He had a positive anterior apprehension test but a negative posterior apprehension test. He had a grade II sulcus sign but that did not reproduce his symptoms. He could be subluxed over the rim when performing laxity testing of his shoulder, and that reproduced his symptoms, only he said his instability episodes were worse. He had some signs of generalized joint laxity but was within normal limits. DIFFERENTIAL DIAGNOSIS Traumatic anterior dislocations. Multi-directional instability. Voluntary instability with possible psychological component. Connective tissue disorder. TESTS AND RESULTS Plain radiographs (AP and axillary of shoulder): Normal with no Hill-Sachs lesion or bony Bankart lesion. MRI of the shoulder: normal. Plain radiographs from emergency room: anterior dislocation shoulder. Diagnostic arthroscopy: avulsion of glenohumeral ligaments from humeral side (HAGL lesion). FINAL/WORKING DIAGNOSIS Traumatic anterior dislocation due to HAGL lesion. TREATMENT AND OUTCOMES At time of arthroscopy open repair of HAGL lesion with subscapularis splitting approach and suture anchors placed in proximal humerus. At six weeks postoperatively stiffer than expected: radiographs suggest humeral head avascular necrosis. MRI show AVN process humeral head. Protected range of motion with no strengthening, MRI's every three months. AVN repaired and resolved at nine months and returned to sports with no limitations.

Modification of the Subscapularis Splitting Technique for Anterior Shoulder Reconstructions

One approach to the anterior shoulder for stabilization of shoulder instability is the subscapularis splitting approach. We have modified this technique and the instrumentation for use on 154 shoulders. The procedure was performed for 118 patients with traumatic anterior instability, 12 for multidirectional instability, and 24 for painful impingement with presumed instability. 27 of these were revision cases. This technique can be used for repairing Bankart lesions and capsular lesions and for bone grafting procedures to the anterior glenoid. There was only one axillary nerve neuropraxia and one partial laceration of the biceps tendon. This technique is safe and effective for treating a variety of instability patterns.