Rethinking surgical strategy in the management of obstetrical palsy

Introduction

Initiated during the widespread use of the operating microscope for nerve repairs, the generally accepted strategy for treating obstetric paralysis is far from satisfactory. Here I propose a completely different approach based on my clinical observation of patients of all ages who have never been treated surgically. Early nerve surgery usually targets the shoulder and elbow flexion (Boome and Kaye, 1988; El-Sayed, 2017; Terzis and Kokkalis, 2009; Waters, 1999), but this has not been supported by sound evidence. After examining over 1000 non-operated patients over almost four decades and in three different countries, I have never encountered anyone who has not recovered active contraction of shoulder muscles or relatively strong elbow flexion. Other surgeons also recorded natural history of recovery of elbow flexion after this injury managed without nerve repair (Gilbert and Tassin, 1987; Hems et al., 2017; Narakas, 1987). Whatever nerve surgery or not have been done, most of the sequelae are not well treated. The observed after-effects of the obstetrical palsy reside at four levels: the shoulder, elbow, forearm and hand.

Shoulder sequelae

These are by far the most common. At a minimum, there is an active and passive external rotation deficit that causes the clarion sign. At the maximum, one can observe dramatically reduced abduction and, in adulthood, very disabling or unbearable pain. In these latter cases imaging shows a developmental absence of the glenoid and a hypotrophic humeral head, which results in some cases in a complete posterior dislocation. Our surgical experience has shown that an early relocation of the humeral head allows, over time, a complete remodelling of the joint leading to a congruent glenoid cavity and a humeral head aligned along the axis of the scapular body, as also noted by other surgeons (Kambhampati et al., 2006). This is similar in concept to surgical treatment of congenital hip dislocation, where relocation of the femoral head allows for the development of an almost normal acetabulum.

The questions arise, when to operate and what to do? When passive external rotation of a young child's shoulder is limited, an anterior release with resection of the horizontal (hypertrophied) part of the coracoid apophysis and section of the coracohumeral ligament and the joint capsule should be performed. The sooner the better, but even late releases have a beneficial effect when there is still potential for growth (Waters and Bae, 2005). In patients who are not treated surgically, in case of a well-aligned humeral head and in the absence of pain, a humeral shaft derotation may still be indicated (Waters and Bae, 2006). For most adults and in cases of disabling pain, a well-positioned shoulder arthrodesis produces dramatic functional gains (Belkheyar et al., 2019). We should not forget that the scapula-thoracic interface is intact in plexic paralysis. In this regard, the sacrifice of the spinal accessory nerve during early nerve surgery must be rigorously avoided, because in addition to the very questionable immediate results, it severely compromises the result of arthrodesis if it is needed later.

The after-effects on the elbow

Contrary to popular belief, in my experience elbow flexor muscles in patients with obstetrical paralysis always regain good strength (Grade 4). A simultaneous contraction of the elbow flexors and extensors can occur and sometimes severely limit bending. In these cases of co-contraction, the treatment completely differs from that for paralysis. At the elbow, the most common sequelae is a passive, or simultaneously passive and active, extension deficit, and the problem is joint stiffness. Unlike the shoulder, the elbow joint is a constrained joint; it does not deform in case of either transient or permanent paralysis of muscles crossing the elbow. Surgical release, even in adulthood, is possible and often desirable. In case of persistent paralysis of the extensor muscles, which is rare except for those undergoing nerve procedures, a transfer of the entire deltoid muscle to the triceps ensures restoration of elbow extension. The functional and aesthetic gain is considerable.

Forearm sequelae

The supinated forearm should be corrected as soon as possible. Early on, when there is a permanent but passively reducible supination, a transfer of the biceps tendon to the brachialis tendon removes the supination effect and prevents deformation of the forearm bones. In many cases the rerouting increases the flexion posture because the biceps is short and in some cases results in hyper-pronation. When the forearm is fixed in supination, osteotomies are required. Crucially, they must be systematically accompanied by a transfer of the biceps to the brachialis in young children, otherwise growth will cause a recurrence.

The after-effects on the hand

These after-effects are the most serious, because they lack a really good solution, whether through nerve surgery or palliative treatments. In adults, wrist arthrodesis is a prerequisite for muscle transfers to power finger and thumb flexion. The donor muscles are individualized and can reside in the forearm or in the arm if necessary, for instance, prolonging the biceps with a tendon graft.

What is the place of early nerve surgery?

I am not convinced that there are indications for early nerve surgery. The only indication could concern the hand, the only sequel we do not know how to deal with. Thus far no nerve surgery directed at improving hand function is available.

Early nerve surgery is rarely indicated (Maillet and Romana, 2009), if necessary at all. In rare cases, nerve surgery from plexic roots or nerve transfers may be performed. But from our experience and the literature, no clear indication emerges (Pondaag and Malessy, 2021). The most severe consequences of obstetric paralysis that I had the opportunity to treat all corresponded to paralysis treated by early nerve surgery. The sacrifice of the spinal accessory nerve must absolutely be avoided.

Summary of my suggestions and current approaches

The best treatment of the obstetrical palsy is prevention. Obstetrical palsy is an iatrogenic lesion. Law suits are making doctors more careful in avoiding obstetrical palsies. Hopefully, we will deal with fewer cases of obstetrical palsies in the future. For a long time, the standard treatment of the obstetrical palsy has been based on early nerve surgery. However, the main sequels we have observed are due to incorrect treatment of the deficits or due to devastating early nerve surgery. Therefore, a different approach should be considered and designed to prevent and treat the main deficits.