Obstetric Brachial Plexus Lesions Research Articles

Validation and Cultural Adaptation of the Serbian Version of the Pediatric Outcome Data Collection Instrument (PODCI) in Children with Obstetrical Brachial Plexus Lesion.

Background and objectives: Pediatric Outcome Data Collection Instrument (PODCI) is among the most described scales developed to evaluate the physical status of children and adolescents with various musculoskeletal disorders. We aimed to translate PODCI from English to Serbian, culturally adopt items and domains, evaluate the temporal stability, internal consistency and the test–retest reliability of PODCISR in children with obstetrical brachial plexus lesion (OBPL), and finally, to test the construct validity of PODCISR against muscular manual test (MMT) Materials and Methods: The study included 48 eligible participants aged between 2 and 10 years with OBPL. The MMT was used to test the construct validity. Results: There were no significant differences (p > 0.05) between test and retest for all PODCISR domains. Correlations for all tested domains with MMT were statistically significant except for biceps muscle and domains II and IV. Cronbach’s alpha value of the Global Functioning Scale was good and equaled 0.838 for test and 0.832 for retest session. Cronbach’s α was more than 0.600 for all PODCISR domains except for Domain II and for Domain IV. The observed Test–Retest ICC for all PODCISR domains scores ranged from 0.899 to 0.996. Conclusion: The Serbian version of PODCI (PODCISR) was successfully translated and transculturally adopted. It has satisfactory temporal stability, construct validity and test–retest reliability as well as relevant internal consistency.

The Effect of Distal Transfer of the Spinal Accessory Nerve to the Suprascapular Nerve on the Shoulder Reanimation in Spontaneously Partially Recovered Obstetric Brachial Plexus Lesion.

Spontaneous recovery of elbow flexion in obstetric brachial plexus palsy at 4 to 6 months of age is sufficient to exclude the child from the early microsurgical intervention. However, lack of complete active external rotation of shoulder is a common finding in such cases despite ongoing other arm and shoulder functions. Nerve transfer is proposed to manage such cases before the age of 18 months. The aim of this study was to study the distal transfer of the spinal accessory nerve to the suprascapular nerve through posterior approach and its effect on the shoulder reanimation in patients with obstetric brachial plexus lesion who had spontaneously recovered biceps function but not shoulder function before the age of 18 months. This prospective study included 20 patients admitted to Elhadra University Hospital with obstetric brachial plexus lesion aged between 10 and 18 months with spontaneous recovery of biceps function, weak active shoulder abduction grade 4 or grade 5 and deficient active shoulder external rotation. All patients were assessed preoperative and postoperative by Active Movement Scale. Active shoulder external rotation improved in all patients at the end of follow-up period, whereas the shoulder abduction improved in 80%. Early surgery in patient younger than 16 months shows better results. The distal transfer of spinal accessory nerve to suprascapular nerve is an effective method for active shoulder abduction and external rotation recovery in spontaneously recovered elbow flexion in obstetric brachial plexus lesions. Better results are obtained in patients younger than 16 months old. Early transfer balances the forces around the shoulder joint, preventing shoulder internal rotation contracture.

Commentary on "Assessment of Motor Repertoire in 3- to 5-Month-Old Infants With Obstetric Brachial Plexus Lesion".

Commentary on "Assessment of Motor Repertoire in 3- to 5-Month-Old Infants With Obstetric Brachial Plexus Lesion".

The components of shoulder and elbow movements as goals of primary reconstructive operation in obstetric brachial plexus lesions

Most of the cases of obstetric brachial plexus lesions (OBPL) show satisfactory improvement with conservative management, but in about 25% some surgical treatment is indicated. The present paper analyzes the effects of primary reconstructive surgeries in aspect of achieving delineated intraoperatively goals.Children operated before the age of 18 months with follow-up period longer than 1 year were selected. Therapeutic goals established during the operation were identified by analysis of initial clinical status and operative protocols. The elementary movement components in shoulder and elbow joints were classified by assessing range of motion, score in Active Movement Scale and modified British Medical Research Council scale of muscle strength. The effect was considered satisfactory when some antigravity movement was possible, and good when strength exceeded M3 or antigravity movement exceeded half of range of passive movement.In 13 of 19 patients most of established goals were achieved at good level, in 2 at satisfactory level. Remaining 4 patients showed improvement only in some aspects of extremity function. In 2 patients improvement in some movements was accompanied by worsening of other movements.The analysis of results separated into individual components of movements showed that goals were achieved in most of the cases, simultaneously clearly indicating which damaged structures failed to provide satisfactory function despite being addressed intraoperatively.The good results were obtained mainly by regeneration through grafts implanted after resection of neuroma in continuity, which proves that this technique is safe in spite of unavoidable temporary regression of function postoperatively.

Glenoid morphology in obstetrical brachial plexus lesion: a three-dimensional computed tomography study

Obstetric brachial plexus lesion (OBPL) frequently leads to glenohumeral dysplasia, and excessive retroversion of the glenoid is among the best known developmental disturbances. Most analyses of the glenoid are based on 2-dimensional (D) imaging and do not address glenoid inclination or provide information on the glenoid in the sagittal plane. We aim to describe the 3-D deformity of the glenoid in children with OBPL. Preoperative computed tomography (CT) scans of the nonaffected and the affected scapula of 24 children (aged 5 to 12 years) with developmental disturbances after OBPL years were analyzed. The dimensions of the scapula and the deformation of the glenoid were visualized in 3-D. The retroversion of the glenoid fossa was greater in all affected shoulders, and 2-D measurements significantly overestimated retroversion compared with angles measured in 3-D. The inclination of the glenoid fossa was altered, and a distal bony edge loss was observed on 3-D reformations in the sagittal plane. The reliability of the measured angles was excellent, and the κ agreement for the description of the glenoid form was substantial. Furthermore, the dimensions of the scapula were significantly smaller on the affected shoulders. OBPL is indeed a 3-D disorder. Our measurements revealed excessive retroversion of the glenoid fossa, and the reliability of the 3-D CT measurements was superior to their 2-D counterparts. 3-D CT reformations of the glenoid in the coronal and the sagittal plane added further to 3-D understanding of glenoid morphology in OBPL. These new findings legitimatize a 3-D CT-based description of the glenoid deformities connected with OPBL.

The use of thermoplastic splints in the reeducation of children with obstetrical brachial plexus palsy

With the advent of the use of thermoplastic splints for the treatment of hand defects in our country, an important factor is addressed, which is the continuous follow-up of children with brachial plexus lesion. The lack of insurance schemes, the scarcity of rehabilitation centres, poverty in families and ignorance of physiotherapeutic treatment and its outcome, makes the continuous follow-up of children who have had an obstetrical brachial plexus lesion very difficult. We present a case of a child of six years with a right brachial plexus lesion at the level of C7–T1 whom we consulted at 11 months old and now 6 years old, respectively. The shoulder and the elbow are not greatly affected. The wrist is flexed and this affects the use of the arm. Due to the lack of insurance coverage, little financial viability and the long distance needed to be covered for therapy, he did not pursue physiotherapy. We decided to make a thermoplastic splint with about 30° extension of the wrist supporting the metacarpals but leaving the MCP free with a little divide of the interdigital space of thumb and index finger. He is coming to therapy twice a week while on vacation but cannot do so when school begins. After three months, the use of this splint has been successful because it permits the child to use both upper limbs in play. With the splint, he has also been able to pick up a pen and is learning to write with his right hand. He can also play and throw a ball with both hands unlike before. He can employ the mirror effect and strengthen the muscles in daily living. The muscle imbalance, which can be observed because of lack of use of the right arm. He will willingly even though unconsciously carry out his therapy at home while playing. He will not travel distances, pay more sessions of therapy than they can afford. His parents will be his first therapist and himself. In our milieu, therefore it is important to learn and properly apply this method since most children who need to continue therapy for long have financial difficulties. This evolution will satisfy both patient and therapist at lower cost and ensure proper social inclusion.

Degree of Contracture Related to Residual Muscle Shoulder Strength in Children with Obstetric Brachial Plexus Lesions.

Little is known about the relation between residual muscle strength and joint contracture formation in neuromuscular disorders. This study aimed to investigate the relation between residual muscle strength and shoulder joint contractures in children with sequelae of obstetric brachial plexus lesion (OBPL). In OBPL a shoulder joint contracture is a frequent finding. We hypothesize that residual internal and external rotator strength and their balance are related to the extent of shoulder joint contracture. Clinical assessment was performed in 34 children (mean 10.0 years) with unilateral OBPL and Narakas classes I-III. External and internal rotation strengths were measured with the shoulder in neutral position using a handheld dynamometer. Strength on the affected side was given as percentage of the normal side. Contracture was assessed by passive internal and external rotations in degrees (in 0° abduction). Mallet classification was used for active shoulder function. External and internal rotation strengths on the affected side were approximately 50% of the normal side and on average both equally affected: 56% (SD 18%) respectively 51% (SD 27%); r = 0.600, p = 0.000. Residual strengths were not related to passive internal or external rotation (p > 0.200). Internal rotation strength (r = - 0.425, p <0.05) was related to Narakas class. Mallet score was related to external and internal rotation strengths (r = 0.451 and r = 0.515, respectively; p < 0.01). The intuitive notion that imbalances in residual muscle strength influence contracture formation cannot be confirmed in this study. Our results are of interest for the understanding of contracture formation in OBPL.

Functional Outcomes of Nerve Reconstruction in Severe Obstetric Brachial Plexus Palsy

Background Microsurgical era has brought a renewed interest in the management of birth-related brachial plexus palsy. There is a general agreement that severe obstetric palsy should be treated by an early nerve reconstruction. Patients and Methods This report is an experience in the primary nerve reconstruction in 32 cases of obstetric brachial plexus lesions in the age group 3.5 to 23 months. Parietal injuries were most commonly associated with truncal neuromas. Conducting neuromas were subjected to neurolysis, whereas nonconducting neuromas were treated by resection and nerve grafting. Restoration of hand functions was a priority in total lesions. In total palsy, a viable root stump if available was connected with nerve grafts to the distal nerve, primarily targeted toward the hand, and nerve transfers were performed for shoulder and elbow. Results A total of 20 patients had C5, C6 injuries and 5 had an associated C7 injury. Seven patients presented with total palsy. The follow-up period ranged from 14 to 42 months. Patients with partial palsy and early surgical intervention produced good functional results in relation to the elbow and shoulder. Recovery in hand function in total palsy was satisfactory to poor. Conclusion Microsurgical reconstruction is indicated for those infants who fail to recover antigravity biceps flexion by 4 to 6 months of age. An early intervention by 3 months is desirable in total palsy.

Long-term outcome of accessory nerve to suprascapular nerve transfer in obstetric brachial plexus lesion: functional, morphological, and electrophysiological results.

An accessory to suprascapular nerve (XIN-SSN) transfer is considered in patients with obstetric brachial plexus lesion who fail to recover active shoulder external rotation. The aim of this study was to evaluate the quality of extraplexal suprascapular nerve neurotization and to perform a detailed analysis of the infraspinatus muscle (IM) and shoulder external rotation. A XIN-SSN transfer was performed in 14 patients between 2000 and 2007. Patients had been operated at the age of 3.7 ± 2.8 years. Follow-up examinations were conducted up to 8.5 ± 2.5 years. Magnetic resonance imaging was performed to investigate muscle trophism. Fatty muscle degeneration of the IM was classified according to the Goutallier classification. We conducted nerve conduction velocity studies of the suprascapular nerve and needle electromyography of the IM to assess pathologic spontaneous activity and interference patterns. Active glenohumeral shoulder external rotation and global shoulder function were evaluated using the Mallet score. Postoperatively, growth of the IM increased equally on the affected and unaffected sides, although significant differences of muscle thickness persisted over time. There was only grade 1 or 2 fatty degeneration pre- and postoperatively. Electromyography of the IM revealed a full interference pattern in all except one patient, and there was no pathological spontaneous activity. Glenohumeral external rotation as well as global shoulder function increased significantly. Our results indicate that the anastomosis after XIN-SSN transfer is functional and that successful reinnervation of the infraspinatus muscle may enable true glenohumeral active external rotation.

Elbow Flexion Contractures in Childhood in Obstetric Brachial Plexus Lesions: A Longitudinal Study of 20 Neurosurgically Reconstructed Infants with 8-Year Follow-up.

Little knowledge exists on the development of elbow flexion contractures in children with obstetrical brachial plexus lesion (OBPL). This study aims to evaluate the prognostic significance of several neuromuscular parameters in infants with OBPL regarding the later development of elbow flexion contractures. Twenty infants with OBPL with insufficient signs of recovery in the first months of life who were neurosurgically reconstructed were included. At a mean age of 4.6 months, the following neuromuscular parameters were assessed: existence of flexion contractures, cross-sectional area (CSA) of upper arm muscles on MRI, Narakas classification, EMG results, and elbow muscle function using the Gilbert score. In childhood at follow-up at mean age of 7.7 years, we measured the amount of flexion contractures and the upper arm peak force (Newton). Statistical analysis is used to assess relations between these parameters. Flexion contractures of greater than 10 degrees occurred in 55% of our patient group. The relation between the parameters in infancy and the flexion contractures in childhood is almost nonexistent. Only the Narakas classification was related to the development of flexion contractures in childhood (p = 0.006). Infant muscle CSA is related to childhood peak muscle force. The role of infancy upper arm muscle hypotrophy/hypertrophy, reinnervation, and early elbow muscle function in the development of childhood elbow contractures remains unclear. In this cohort prediction of childhood flexion, contractures were not possible using infancy neuromuscular parameters. We suggest that contractures might be an adaptive process to optimize residual muscle function.

Explaining daily functioning in young adults with obstetric brachial plexus lesion

Purpose: To study the influence of obstetric brachial plexus lesion (OBPL) on arm–hand function and daily functioning in adults, and to investigate the relationship of arm-hand function and pain to daily functioning. Method: Adults with unilateral OBPL who consulted the brachial plexus team at the VU University Medical Center in the past were invited to participate. Daily functioning was measured with the Disability of the Arm, Shoulder and Hand (DASH) questionnaire and the SF36, pain with VAS Pain Scales and arm-hand function with the Nine Hole Peg Test (9-HP-test) and the Action Research Arm Test (ARAT). Scores of the affected arm were compared to those of the non-affected arm or norm values for healthy controls. Results: Twenty-seven persons (mean age 22, SD 4.2 years), of whom 10 men, participated. The ARAT and 9-HP-test scores for the affected arm were significantly worse than those for the non-affected arm. Moderate to severe pain in the affected arm, the non-affected arm or the back was reported by 50% of the participants. The DASH general, sports/music and SF36 physical functioning scores were significantly worse than norm values. The ARAT/9-HP-test and daily functioning showed little association. Low to moderate associations were found between pain and daily functioning. Conclusions: Many young adults with OBPL experience limitations in daily functioning. Pain, rather than arm-hand function, seems to explain these limitations.Implications for RehabilitationObstetric brachial plexus lesion (OBPL) is caused by traction to the brachial plexus during labour, resulting in denervation of the muscles of the arm and shoulder girdle.Adults with OBPL are hardly seen in rehabilitation medicine.This study shows that many young adults with OBPL experience limitations in daily functioning. Pain, rather than arm-hand function, seems to explain these limitations.Fifty percent of the participants complained about moderate or severe pain, which was located in the affected arm, the back and the non-affected arm. There seems an age-related increase in pain prevalence.Persons who had undergone plexus surgery had a significantly worse arm-hand function, but comparable scores on daily functioning scales compared to persons without plexus surgery.When limitations in daily functioning or pain occur, referral to a rehabilitation physician is indicated.

Clinical and neuropathological study about the neurotization of the suprascapular nerve in obstetric brachial plexus lesions

BackgroundThe lack of recovery of active external rotation of the shoulder is an important problem in children suffering from brachial plexus lesions involving the suprascapular nerve. The accessory nerve neurotization to the suprascapular nerve is a standard procedure, performed to improve shoulder motion in patients with brachial plexus palsy.MethodsWe operated on 65 patients with obstetric brachial plexus palsy (OBPP), aged 5-35 months (average: 19 months). We assessed the recovery of passive and active external rotation with the arm in abduction and in adduction. We also looked at the influence of the restoration of the muscular balance between the internal and the external rotators on the development of a gleno-humeral joint dysplasia. Intraoperatively, suprascapular nerve samples were taken from 13 patients and were analyzed histologically.ResultsMost patients (71.5%) showed good recovery of the active external rotation in abduction (60°-90°). Better results were obtained for the external rotation with the arm in abduction compared to adduction, and for patients having only undergone the neurotization procedure compared to patients having had complete plexus reconstruction. The neurotization operation has a positive influence on the glenohumeral joint: 7 patients with clinical signs of dysplasia before the reconstructive operation did not show any sign of dysplasia in the postoperative follow-up.ConclusionThe neurotization procedure helps to recover the active external rotation in the shoulder joint and has a good prevention influence on the dysplasia in our sample. The nerve quality measured using histopathology also seems to have a positive impact on the clinical results.

An MRI study on the relations between muscle atrophy, shoulder function and glenohumeral deformity in shoulders of children with obstetric brachial plexus injury

BackgroundA substantial number of children with an obstetric brachial plexus lesion (OBPL) will develop internal rotation adduction contractures of the shoulder, posterior humeral head subluxations and glenohumeral deformities. Their active shoulder function is generally limited and a recent study showed that their shoulder muscles were atrophic. This study focuses on the role of shoulder muscles in glenohumeral deformation and function.MethodsThis is a prospective study on 24 children with unilateral OBPL, who had internal rotation contractures of the shoulder (mean age 3.3 years, range 14.7 months to 7.3 years). Using MR imaging from both shoulders the following parameters were assessed: glenoid form, glenoscapular angle, subluxation of the humeral head, thickness and segmental volume of the subscapularis, infraspinatus and deltoid muscles. Shoulder function was assessed measuring passive external rotation of the shoulder and using the Mallet score for active function. Statistical tests used are t-tests, Spearman's rho, Pearsons r and logistic regression.ResultsThe affected shoulders showed significantly reduced muscle sizes, increased glenoid retroversion and posterior subluxation. Mean muscle size compared to the normal side was: subscapularis 51%, infraspinatus 61% and deltoid 76%. Glenoid form was related to infraspinatus muscle atrophy. Subluxation was related to both infraspinatus and subscapularis atrophy. There was no relation between atrophy of muscles and passive external rotation. Muscle atrophy was not related to the Mallet score or its dimensions.ConclusionMuscle atrophy was more severe in the subscapularis muscle than in infraspinatus and deltoid. As the muscle ratios are not related to passive external rotation nor to active function of the shoulder, there must be other muscle properties influencing shoulder function.

Free functional gracilis muscle transfer in children with severe sequelae from obstetric brachial plexus palsy

We present 4 children between 6 and 13 years suffering from severe sequelae after a total obstetric brachial plexus lesion resulting in a hand without functional active long finger flexion. They had successfully reanimated long finger flexion using a free functional gracilis muscle transfer. These children initially presented a total obstetric brachial plexus palsy without neurotisation of the lower trunk in an early microsurgical nerve reconstruction procedure.We describe our indications for this complex microsurgical procedure, the surgical technique and the outcome.

Microsurgical technique in obstetric brachial plexus repair: a personal experience in 200 cases over 10 years

We present our personal operative technique in exposing and repairing obstetric brachial plexus (obp) lesions. This technical description of the operative procedure and the strategic choice for the neurotisations are analysed with special regards on the follow-up of these patients (always performed by the surgeon), the histological quality of the proximal root stumps used for cable grafting, and the general reconstruction principles established in international workshops.We would like to encourage debate on these detailed considerations wherever they could affect the functional outcome.

Augmentation of partially regenerated nerves by end-to-side side-to-side grafting neurotization: experience based on eight late obstetric brachial plexus cases

ObjectiveThe effect of end-to-side neurotization of partially regenerated recipient nerves on improving motor power in late obstetric brachial plexus lesions, so-called nerve augmentation, was investigated.MethodsEight cases aged 3 – 7 years were operated upon and followed up for 4 years (C5,6 rupture C7,8T1 avulsion: 5; C5,6,7,8 rupture T1 avulsion:1; C5,6,8T1 rupture C7 avulsion:1; C5,6,7 ruptureC8 T1 compression: one 3 year presentation after former neurotization at 3 months). Grade 1–3 muscles were neurotized. Grade0 muscles were neurotized, if the electromyogram showed scattered motor unit action potentials on voluntary contraction without interference pattern. Donor nerves included: the phrenic, accessory, descending and ascending loops of the ansa cervicalis, 3rd and 4th intercostals and contralateral C7.ResultsSuperior proximal to distal regeneration was observed firstly. Differential regeneration of muscles supplied by the same nerve was observed secondly (superior supraspinatus to infraspinatus regeneration). Differential regeneration of antagonistic muscles was observed thirdly (superior biceps to triceps and pronator teres to supinator recovery). Differential regeneration of fibres within the same muscle was observed fourthly (superior anterior and middle to posterior deltoid regeneration). Differential regeneration of muscles having different preoperative motor powers was noted fifthly; improvement to Grade 3 or more occurred more in Grade2 than in Grade0 or Grade1 muscles. Improvements of cocontractions and of shoulder, forearm and wrist deformities were noted sixthly. The shoulder, elbow and hand scores improved in 4 cases.LimitationsThe sample size is small. Controls are necessary to rule out any natural improvement of the lesion. There is intra- and interobserver variability in testing muscle power and cocontractions.ConclusionNerve augmentation improves cocontractions and muscle power in the biceps, pectoral muscles, supraspinatus, anterior and lateral deltoids, triceps and in Grade2 or more forearm muscles. As it is less expected to improve infraspinatus power, it should be associated with a humeral derotation osteotomy and tendon transfer. Function to non improving Grade 0 or 1 forearm muscles should be restored by muscle transplantation.Level of evidenceLevel IV, prospective case series.

Discrepancy between strength and function in adults with obstetric brachial plexus lesions.

This commentary is on the original article by Anguelova et al. on pages 984–989 of this issue.

Extensive motor axonal misrouting after conservative treatment of obstetric brachial plexus lesions.

The aim of this cross-sectional study was to assess systematically motor function and motor misrouting in adults with conservatively treated obstetric brachial plexus lesion (OBPL). Seventeen adults with OBPL (median age 38y; five males, 12 females) and 16 comparison participants (median age 26y; eight males, eight females) were investigated. Motor function in the group with OBPL was assessed through passive and active motion, muscle strength of the deltoid, biceps, and triceps muscles, and Mallet aggregate score and five subscores. Motor misrouting was quantified by electrically stimulating each of 10 arm muscles and recording activity from the other nine in response to this. Motor function and motor misrouting were statistically analysed using the Mann-Whitney U test and Spearman's correlation coefficient. Motor function testing showed excellent strength but poor functional Mallet scores. Participants with OBPL had significantly more motor misrouting than comparison participants (Mann-Whitney U=31.5 [df=28], p<0.001, median difference=-4.00, 95% confidence interval [CI]=-7.00 to -1.00). Most misrouting was observed when stimulating the biceps (Mann-Whitney U=38.5 [df=31], p<0.001, median difference=-3.00, 95% CI -3.00 to -1.00), deltoid (Mann-Whitney U=68.5 [df=31], p=0.003, median difference=-1.0, 95% CI=-4.00 to 0.00 <0.001) and brachioradialis muscles (Mann-Whitney U=72.0 [df=31], p=0.002, median difference <0.001, 95% CI=-3.00 to 0.00 <0.001). There were no significant correlations between the presence of motor misrouting and impairment of motor function. There is extensive motor misrouting in conservatively treated OBPL. The presence of this, in addition to motor functional impairment, suggests that motor misrouting should be further studied in OBPL.

Intercostal and pectoral nerve transfers to re-innervate the biceps muscle in obstetric brachial plexus lesions

In obstetric brachial plexus lesions with avulsion injury, nerve grafting for biceps muscle re-innervation may not be possible owing to the unavailability of a proximal stump. In such cases, the intercostal nerves or medial pectoral nerve can serve as donor nerves in an end-to-end transfer to the musculocutaneous nerve. The present study reports the results of both techniques from a single institution in a consecutive series of 42 patients between 1995 and 2008. From 1995 to 2000 we always used the intercostal nerve transfer, and from 2001 to 2008 both techniques were used. Biceps muscle force ≥ Medical Research Council Grade 3 was achieved in 37 of 42 patients after a mean follow-up of 44 months. There was no statistical difference in the results in the medial pectoral nerve transfer group (n = 25) and the intercostal nerve transfer group (n = 17).

Scapular deformity in obstetric brachial plexus palsy and the Hueter-Volkmann law; a retrospective study

BackgroundThe Hueter-Volkmann law describes growth principles around joints and joint deformation. It states that decreased stress leads to increased growth and that excessive stress leads to growth retardation. Aim of this study was to test the possible results of this principle by measuring the effect of dorsal humeral head subluxation on scapular growth in children with Obstetrical Brachial Plexus Lesions (OBPL). According to the Hueter-Volkmann law, subluxation should result in decrease of growth of the dorsal length of the scapula (by increased dorsal pressure) and increase of the ventral length (decreased pressure).Methods58 children (mean age 20 months, range 1-88 month) with unilateral OBPL and good quality MRI of both shoulders were included. On MRI, humeral head subluxation, joint deformation, and ventral and dorsal scapular lengths were measured. Data were expressed as a ratio of the normal side.ResultsIn affected scapulas both ventral and dorsal side were smaller compared to the normal side. Reduction of growth on the affected side was more marked on the dorsal side than on the ventral side (6.5 mm respectively 4.5 mm, p < 0.001). The balance of growth reduction as expressed by the ratio of ventral and dorsal length was strongly related to subluxation (R2 = 0.33, p < 0.001) and age (R2 = 0.19, p < 0.001).ConclusionsThe Hueter-Volkmann law is incompletely active in subluxated shoulders in OBPL. Dorsal subluxation indeed leads to decrease of growth of the dorsal length of the scapula. However, decreased stress did not lead to increased growth of the ventral length of the scapula.