Reach out and grasp the opportunity: reconstructive hand surgery in tetraplegia

Abstract

Reconstructive upper extremity surgeries in tetraplegia are technically challenging because of the many complicated real-time decisions that need to be made, e.g. extent of release of donor muscle-tendon complex, routing of donor muscles, tissue preparation and optimization, tensioning of muscle-tendon units, balancing joints and suturing tendon-to-tendon attachments. Nerve transfer surgeries can add functionality but also make the reconstruction planning more complex. In this overview, we present some of the fundamental muscle-tendon-joint mechanics studies that allow for single-stage surgical reconstruction of hand function as well as early postoperative activity-based training in patients with cervical spinal cord injuries. We foresee an increased need for studies addressing combined nerve and tendon transfer reconstructions in parallel with patient-perceived outcome investigations. These should be combined with implementation of assistive technology such as functional electrical stimulation for diagnostic, prognostic and training purposes.

Introduction

Cervical spinal cord injuries are catastrophic events that radically alter an individual’s ability to perform most normal activities of daily life. Individuals consider upper limb control to be the most desirable ability to regain after cervical spinal cord injury (Anderson, 2004). An increased awareness among patients and caregivers of available surgical techniques to improve motor function has amplified the interest and scientific efforts in this field. Furthermore, surgical rehabilitation of the upper limb in tetraplegia is highly beneficial and rewarding from a patient perspective, with an up to 95% satisfaction rate (Bunketorp et al., 2017). Not only have satisfactory gains in activities of daily living been documented, but also enriched quality of life (Bunketorp et al., 2017b). From a surgical point of view, a better understanding of the complex interactions between muscles, tendons and joints in the normal as well as in the paralysed individual has been a prerequisite for this development, much thanks to long-term close cooperation with basic scientists in several fields including muscle and nerve physiology, kinetics and kinematics.

With specialized spinal cord injury units and better coordination of the multiple levels of care, we can anticipate a greater number of patients with normal life expectancy in the future. In addition, tetraplegic individuals are now better informed about the benefits of surgery through social media and comprehensive home pages; this will likely increase the demand for more surgical reconstructions.

Efforts over the past 50 years

Surgical reconstructions can improve upper extremity function in tetraplegia and have been undertaken for more than 50 years (Bunnell, 1948; Freehafer et al., 1974; Lipscomb et al., 1958). Initially, the operations focused on higher lesions and included tenodesis of the flexor pollicis longus (FPL) tendon to the distal radius and usually also fusion of the carpal metacarpal (CMC) joint of the thumb combined with tenodesis of the extensor pollicis longus (EPL) tendon to the extensor retinaculum (Moberg, 1975). This reconstruction enabled both pinch (flexion) and extension of the thumb. In lower cervical lesions with more functions preserved, additional procedures with good outcomes were presented. Finger flexion reconstruction was introduced as an adjunct to thumb flexion (House et al., 1976). The extensor carpi radialis longus (ECRL) muscle was a suitable substitute to deep finger flexors for two reasons: it has a long muscle-tendon excursion and it is promptly recruited in the synergistic motion (e.g. Hentz and Leclercq, 2002). However, substitution of thumb flexion, finger flexion and passive extension of the thumb did not fulfil the need for extension of the fingers to initiate, for example, grasping a glass or shaking a hand. Several reconstructions for active extension of the fingers and simultaneous extension/radial abduction have been proposed. A frequently used donor for this purpose was the pronator teres muscle (Hentz, 2002).

Simultaneous reconstructions of flexors and extensors were fundamentally a conflict because of the need to protect the reconstructions and at the same time to activate these motors differently. Therefore, two-stage reconstructions of hand functions on each side became the primary approach. This strategy required two operations and two immobilization and rehabilitation periods to obtain grip and grasp functions irrespective of the order of flexor and extensor reconstruction.

Our comparisons of different suture technique and our improved understanding of tendon-to-tendon attachment mechanics certainly provided decisive information about mechanical strength and hence options to activate transferred muscle-tendon units immediately after operation (Brown et al., 2010; Tsiampa et al., 2012). Subsequently, we demonstrated a safety factor of 5–10 times stronger for ultimate load to failure than for passive and active tension for brachioradialis (BR-FPL tendon-to-tendon attachment (Fridén et al., 2010). The confidence in the tendonto-tendon attachment strength allowed for immediate postoperative active training of the transferred muscles. Thereby, the donor muscles do not develop disuse atrophy. Moreover, the strong repairs allow the patient to perform more complex activities immediately after surgery. Finally, the repetitive gliding of muscle and tendons is likely to reduce the risk of adhesions compared to postoperative immobilization (Wangdell et al., 2016). The high mechanical strength of our suture technique made us propose a single--stage approach including finger and thumb flexors as well as intrinsics (Fridén et al., 2011).

Our experience and preference

Based on the cumulated experience from more than 1000 reconstructions performed at the Swedish National Centre for Reconstructive Hand Surgery in Tetraplegia, Gothenburg, Sweden and Swiss Paraplegic Centre, Nottwil, Switzerland, we prefer to reconstruct an ‘all in’ closing-opening hand function, providing triceps function is sufficient (existing or previously reconstructed/reinnervated). Some individuals decide to undergo only one reconstruction and are happy with that. If they choose to stop after one reconstruction, only having the extensor function restored would not greatly benefit them functionally. Conversely, if they settle after a complete grip reconstruction according to the approach described below, they have gained a lot of new abilities in daily life.

We believed that a single-stage operation with a more integrated motor relearning after surgery would provide better ability in daily life. Therefore, we developed a combination of procedures that will allow for active thumb and finger flexion, passive extension of the thumb (or active after a successful earlier supinator to posterior interosseous nerve [S-PIN] procedure) (Bertelli et al., 2010) and passive (or active when flexor digitorum superficialis [FDS] functions entirely of partly to power intrinsic lumbrical tasks) proximal interphalangeal (PIP) joint extension of the fingers. We entitled this combined surgical approach the Alphabet operation (Advanced Balanced Combined Digital Extensor Flexor Grip reconstruction) (Fridén et al., 2011). Because of the numerous procedures included in this reconstruction, an increased risk of adhesions was present. By implementing early and rigorous active training of restored functions together with careful and guided mobilization of the tenodeses, adhesions can be avoided and recruitment of transferred muscles can be initiated early. A skilful rehabilitation team including physiotherapists and occupational therapists is essential for this demanding training. In addition, the one-stage reconstruction offers an efficient use of time for surgery/rehabilitation with the same or better outcome. The objective of this overview is to demonstrate how multiple clinical ideas collected over the years have been tested and developed in the biomechanics laboratory before implemented in surgical practice. After implementation, careful outcome studies have been undertaken with focus on patient perceived change of hand control after surgery and rehabilitation. In parallel, rehabilitation protocols have been assessed and refined.

Surgical procedures

Multiple incisions are necessary for the single-stage grip reconstruction (Alphabet) operation; therefore, thorough planning is necessary for the different approaches and the sequence of actions. We prefer making the seven individual operations in the following order: (1) distal EPL tendon duplication (loop knot) (Fridén et al., 2013); (2) carpometacarpal (CMC)1 arthrodesis; (3) reconstruction of passive (or active when feasible) intrinsics; (4) BR-FPL tendon transfer; (5) extensor carpi radialis longus (ECRL)-FDP tendon transfer; (6) EPL-dorsal forearm fascia tenodesis; and (7) extensor carpi ulnaris (ECU) tenorrhaphy (Reinholdt and Fridén, 2013a). This order optimizes tensioning, balancing, accessibility and protection of the completed transfers and arthrodesis. It also allows completion of all surgery in the hand within 2 hours, thus enabling continuation of the operation in the forearm without a bloodless operating field. Our choice of sutures is generally braided non-absorbable 3–0 (forearm) and 4–0 (hand) sutures for tendon attachments.

Distal EPL tendon duplication (loop knot).

The purpose of this procedure is to prevent hyperflexion of the IP joint after being powered by active thumb flexor (BR to FPL). There are two prerequisites for this procedure. First, full passive metacarpophalangeal (MCP) flexion range of motion. If not, too much flexion power will be transferred to the IP joint after the BR-FPL tendon transfer causing a stretch-out or disruption of the duplicated EPL tendon. Second, a complete release of the EPL from the IP and proximally to the MCP joint hood. Unless the demands are met, we recommend the split FPL-EPL distal thumb tenodesis (Mohammed et al., 1992).

An oblique dorsal incision is made from the level of the IP joint reaching proximally to the MCP joint. The EPL tendon is elevated with a hook and a loop is formed and secured at the basis with two knots using non-resorbable braided 3–0 sutures (Figure 1). The loop is then turned onto the EPL tendon itself and fixed with running sutures back and forth on the three sides. The degree of tension should be checked by pulling the FPL tendon at the wrist level. This manoeuvre produces a maximum range of IP flexion of about 30°. Four weeks of K-wire fixation of the IP joint may be necessary to prevent hyperflexion of the IP.

Figure 1.

EPL tendon duplication to prevent hyperflexion of the thumb and allowing active but limited IP joint range of motion. This correction secures a sufficient contact area of the pulp of the thumb and the radial aspect of the index finger. Typically, digits 1 and 2 have the best sensation in patients with C5-C6 tetraplegia.

CMC1 arthrodesis.

CMC1 arthrodesis is performed in a standard manner but with careful adjustments of joint angles. The CMC1 joint is fixed in 30° of radial and palmar abduction as well as 30° of pronation from full supination to ensure that the pulp of thumb meets the radial side of index finger during key pinch (Figure 2). Our C5-C6 tetraplegia patients typically have remaining sensation in thumb and index and benefit from increased sensory-motor feedback after surgery. It is important that arthrodesis in tetraplegic individuals uses a technique that neither requires a second operation to remove hardware nor threaten the skin integrity. A thin T- or Y-shaped plate serves this purpose (Figure 3).

Figure 2.

(a) Radial view of the hand after reconstruction. CMC1 palmar abduction of 30° secures the opening of the hand when wrist is flexed. 30° of pronation from preoperative full supination secures thumb targeting lateral aspect of the distal interphalangeal joint of the index finger. (b) CMC1 30° of radial abduction secures free flexion of the fingers around an object when wrist is flexed. 30° of thumb IP flexion secures maximal contact between thumb and index.

Figure 3.

CMC joint arthrodesis using a Y-plate. This thin plate ensures a stable fusion, securing the direction of the thumb towards the index when performing key pinch. It also allows loading during wheel chair driving and does not require later removal of hardware. Positioning guidelines are given in the legend for Figure 2.

Reconstruction of passive intrinsics.

The purpose of reconstructing the lumbricals is to secure MCP joint flexion, particularly for the index finger. This enables the thumb to meet the radial aspect of the index and also creates support for digits 3–5 (Arnet et al., 2013; Muzykewicz et al., 2013). Contact between the index finger and thumb is crucial because, typically, the patient suitable for grip reconstruction has sensation limited to the thumb and index fingers. Moreover, the relatively straight PIP joints achieved by the House tendon loop reconstruction minimize the risk of PIP hyperflexion during key pinch. Without a secured PIP extension control, the thumb could otherwise slip distal to a hyperflexed index finger when pinching objects. Based on these observations, we prefer an intrinsic reconstruction according to McCarthy (McCarthy et al., 1997).

We also prefer reconstruction of a normal cascade instead of reverse cascade that is sometimes advocated. A normal cascade provides better opening of the hand. Furthermore, extension of the PIP joints is essential for grasp and release and provides a more normal opening. If EDC function is present, related to the level of the lesion or by successful reinnervation after nerve transfer, an intrinsic-minus type of opening would otherwise occur.

For group 5 patients with intact or reinnervated EDC (after S-PIN nerve transfer), we have successfully used the extensor digiti minimi (EDM) to abductor pollicis brevis (APB) tendon transfer to restore voluntary control of palmar abduction of the thumb (Fridén et al., 2010). This extra thumb-positioning ability adds furthering opening of the hand, which can balance the adduction moment caused by a passive EPL-dorsal forearm fascia tenodesis or a reinnervated EPL after S-PIN nerve transfer.

For lumbrical function restoration, the ring finger FDS (or the PL when available and of sufficient size) is harvested from its insertion and, through a palmar mid-forearm incision, the tendon is severed at muscle level and removed. The tendon is then divided into two strands. L-shaped incisions are made on the dorsal aspect of each finger at the proximal phalanx level and 15 mm longitudinal incisions are made at the level of the neck of metacarpals 2 and 4 (Figure 4). With the MCP joints in 80° of flexion, the radial FDS tendon loop slip is tunnelled from the radial aspect of the proximal phalanx of the index finger in proximal direction under the first dorsal interosseus tendon and via the longitudinal incision over the neck of second metacarpal. The tendon slip is brought transversely in an ulnar direction under the EDC2 and EIP tendons. From there, the tendon is passed distally and through the lumbrical canal, i.e. palmar to the intermetacarpal ligaments and onto the extensor hood of the middle finger (McCarthy et al., 1997). Attachment of the tendon slip is made with MCP joints in 80° flexion and PIP joints fully extended. Sutures run back and forth into the lateral band and central band for each insertion. Using the other half of the FDS tendon, the same procedure is repeated for digits 4 and 5 while securing the cascade (Figure 5). The PIP joint extension of all fingers is protected during the rest of the operation. In lower lesions (group 9, Table 1), reconstruction of active intrinsics can be performed (Figure 6).

Figure 4.

Our preferred incisions for intrinsic reconstruction. The long leg of the L-shaped incisions on the fingers are made on the ulnar side of the proximal phalanx and are therefore barely visible. The transverse incisions are made on the dorsal crease over the PIP joint and heal with a good cosmetic result. The longitudinal incisions over the second and fourth metacarpals give access to the lumbrical canals as well as the ‘locking’ mechanisms under EDC2/EIP and EDC4.

Figure 5.

Reconstruction of passive intrinsics with two tendon loops originating and inserting onto the extensor aponeurosis of the proximal phalanges of neighbouring fingers while acting as passive MCP joint flexors when flexing the wrist (actively by functioning FCR or passively by gravity). The intrinsic plus position is secured for all fingers.

Table 1.

The international classification for surgery of the hand in tetraplegia.

Group	Muscle*	Suggested Procedures
0	No muscles	Nerve transfer, triceps reconstruction
1	BR	BR-ECRB, passive key pinch, passive intrinsics, triceps reconstruction
2	ECRL	BR-FDP, passive key pinch, passive intrinsics, triceps reconstruction
3	ECRB	Alphabet reconstruction, triceps reconstruction
4	PT	″
5	FCR	″
6	EDC	Alphabet reconstruction with options
7	Thumb ext	″
8	FDS, FDP (partially)	″
9	Lacks intrinsics	Passive or active intrinsics, EDM-APB

^*Muscles below the elbow with strength grade of minimum 4 are counted (MacDowell et al., 1986). Note that the Alphabet reconstruction can be a feasible treatment option for groups 3–5 but, with modification, also for groups 6–8, i.e. the majority of the patients with cervical spinal cord injury and tetraplegia.

Figure 6.

Reconstruction of active intrinsics. FDS4 is detached at the level of insertion and the two strands are each split longitudinally. Thereafter, they are separately brought into the lumbrical canals on the radial side of the fingers and attached to the lateral and central bands on the radial aspect of each finger.

BR-FPL tendon transfer.

The BR muscle has the longest muscle fibres in the forearm, so it is an almost perfect donor for performing large range of motion tasks (Lieber and Fridén, 2000, 2002; Lieber et al., 2005). Via a curved anterior incision at wrist and distal forearm level, the BR is detached from the radial styloid and meticulously released in proximal direction while protecting the superficial radial nerve. In our experience, fewer adhesions develop after surgery when a skin-subcutaneous bridge of 2–3 cm is left intact at the muscle-tendon junction level. The muscle belly is disconnected from the neighbouring radial wrist extensors and PT by severing fascial bands to obtain a longitudinal mobility of 3–4 cm (Figures 7 and 8). Adequate release and great excursion are critical for the final function of the restored FPL (Fridén et al., 2001). The BR is transferred subcutaneously through a wide tunnel (to reduce risk of adhesions and to allow large lateral translation when rotating the forearm) into the FPL tendon (Figure 9).

Figure 7.

Extensive release of brachioradialis to exploit largest possible excursion for efficient powering of FPL tendon irrespective of wrist and thumb joint positions.

Figure 8.

Representative graph of progressive release of brachioradialis muscle from the radial head and surrounding tissues expressed as a length-time records (release starts from the left) Each colour represents a 3-cm release with the overall release length obtained for each segment shown to the right of the panel. Vertical lines separating colours represent the excursion magnitude after each release. Note that greatest excursion is obtained in the right part of the graph corresponding to the release at muscle level (from mid-forearm level and proximally). From Figure 2 in Fridén et al., Clin Orthop Rel Res. 2001, 383: 154.

Figure 9.

Completed transfer BR-FPL. Running sutures along the sides of donor and recipient tendons, back and forth and on both sides with a 5-cm overlap allow immediate active postoperative training. Load to failure for this suture exceeds 200 N.

ECRL-FDP tendon transfer.

The ECRL tendon is exposed through a transverse incision just distal to the wrist joint and over the insertion at the base of the second metacarpal. Both the ECRL and ECRB tendons should be simultaneously visualized to avoid cutting the ECRB by mistake (Figure 10). The ECRL tendon is clamped with a haemostat, cut, released distally, retracted proximally and tunnelled along the same subcutaneous route as the BR. The ECRL is then temporarily attached to the individual FDP tendons for later tensioning (Figure 11).

Figure 10.

The radial wrist extensors exposed before harvesting ECRL for transfer to FDP. Both ECRL (blue loop) and ECRB (red loop) should be visualized simultaneously to avoid erroneously harvesting the wrong tendon for transfer.

Figure 11.

Donor ECRL tendon brought through recipient tendons FDP2–4. Notice that FDP5 is typically excluded in this transfer.

EPL tenodesis.

The EPL is exposed through an oblique incision on dorsal aspect of the wrist. If ECU tenodesis is needed to rebalance the radial wrist deviation (see below), the incision is extended to the neck of ulna. The third dorsal tendon compartment is opened and the EPL is cut and temporarily sutured to the dorsal fascia with the wrist in the neutral flexion-extension position. The therapist is then passively flexed to 50° to verify a sufficient extension and minimal adduction of the thumb, i.e. a distance of 4–5 cm between the tip of the thumb and index finger. The EPL tendon is then attached to the dorsal fascia using running suture along a 3–5-cm stretch of tendon-fascia overlap (Figure 12). In our experience, this technique provides a stiffer connection than the traditional EPL tendon wrapped around the extensor retinaculum as described by House et al. (1992).

Figure 12.

The EPL is tenodesed to the dorsal forearm fascia just radial to the third dorsal tendon compartment. Adduction moment of the thumb should be limited when wrist is flexed. Suturing EPL tendon side-to-side to EPB tendon proximal to MCP joint reduces this risk.

Now it is time to set the tension of the transfers. Based on intraoperative length-tension measurements (Figure 13), BR muscle tension is optimal for force generation when the distal end of the BR tendon is approximated to its original length while the wrist is in neutral and with the thumb flexed firmly against the index finger when the elbow is in full elbow extension and lightly when elbow is flexed 90°. It is important to make the tensioning correct - too little causes overstretch and unpredictable force generation resulting in a weak pinch (Fridén and Lieber, 1998, 2002; Lieber and Fridén, 2000). Tendon attachment is performed after the donor BR tendon has been brought through a hole in FPL tendon and put onto and along the superficial aspect of FPL tendon. Running suture back and forth along the both sides of tendons with a 5 cm overlap is used (Fridén and Reinholdt, 2008).

Figure 13.

Preparation for intraoperative measurement of length-tension relationship of the BR and ECRL muscles. Tendons connect to a stretching device with a load cell and length-tension relationships are recorded in 5-mm increments of pull.

Finger flexion is obtained by transferring the ECRL tendon through FDP tendons 2–4 with fingers flexed to within 2–3 cm pulp-to-palm distance. This measure is undertaken to protect the reconstructed intrinsic function (see above). The normal cascade is retained while the ECRL is brought obliquely through the FDP tendons and tension is individually set for FDP tendons 2–4 (Figure 14). The donor ECRL tendon is positioned obliquely over the three FDP tendons and attached with a 5-cm overlap with the technique previously described (Fridén et al., 2015). Typically, the FDP5 is not included in this transfer. The FDP5 flexes passively during ECRL activation as a result of its tight connection to neighbouring FDP4 at the muscle belly level. By excluding FDP5, the full flexion of the little finger before the other fingers is avoided after transfer.

Figure 14.

After completion of BR-FPL and ECRL-FDP constructs.

ECU tenorrhaphy for wrist alignment.

ECU tenorrhaphy is a passive tenodesis by shortening the tendon until the wrist is in neutral position in the frontal plane (Reinholdt and Fridén, 2013a). A short incision is made just proximal to the ulnar head. The dorsal sensory branch of the ulnar nerve is protected and the sixth extensor compartment tendon sheath is opened longitudinally. Using a tendon elevator and while an assistant is bringing the wrist joint into maximal ulnar deviation (~40° from neutral), the tendon is lifted to form a loop with a total length of approximately 2 cm (Figure 15). The ECU tendon duplication is secured with 2–3 2–0 braided double-loop sutures and then pushed back into the tendon sheath and secured there to avoid a subcutaneous prominence.

Figure 15.

The ECU tendon is slackened in maximal ulnar deviation of the wrist and shortened by making a tendon loop which is sutured at its base.

After skin suturing and dressing, a palmar plaster is applied with the forearm pronated, the wrist in 30° of extension and maximally deviated ulnarly, the thumb slightly abducted and lightly stretched, and the fingers in 60–80° flexion at the MCP joints with the PIP joints fully extended. The elbow is free to move because it has minimal effect on the tension of the BR-FPL transfer (Fridén et al., 2010).

Rehabilitation protocols

On the first day after surgery, the dressing is changed and active and passive motions are initiated. The fingers and thumb are wrapped individually with soft elastic material. Thereafter, the hand, wrist and forearm are wrapped with an elastic bandage. A removable, custom-made orthosis holds the wrist extended 30° and the fingers in intrinsic plus position (MCP joint 60–80° of flexion, PIP joint 0°). The thumb is kept in the position governed by the CMC arthrodesis and wrist extension, i.e. light touch against the index. Twice or thrice per day, the splint is removed and the patient is instructed on how to activate the ‘new’ motors and tenodeses. This concept has proven efficient in reducing oedema and adhesions as well as facilitating recruitment of donor muscles powering the reconstructed functions. The patient is provided with a written daily schedule while in the hospital as well as written and oral instructions on how to perform the home training programme. When possible, a relative or personal assistant is instructed to oversee and assist in training. After removal of sutures at 2 weeks, activities are then more focused on daily living and hand control.

Outcomes

We use the Canadian Occupational Performance Measurement to assess the outcomes of these surgical procedures and rehabilitation. The patients operated according to the Alphabet single-stage procedure and who complied with the early postoperative training protocol were highly satisfied (increase of 3.7 points) and could perform several of their self-selected goals (3.5 points of improvement) (Reinholdt and Fridén, 2013). Although, there were improvements in both functional factors and in rated performance of prioritized activities after surgery, there was no correlation between performance change and any of the physical functions (Bunketorp et al., 2017a; Wangdell and Fridén, 2011). The gains were subcategorized and linked to the International Classification of Functioning, disability and health (ICF). ICF domains ‘mobility’, ‘self-care’, ‘communication’, ‘domestic life’ and ‘community, social and civic life’, with ‘handling objects’ and ‘manoeuvring a wheelchair’ as the most frequently reported gains (Bunketorp et al., 2017b). This latter study reconfirmed the lack of significant correlation between grip strength and activity gains and between grip strength and perceived overall health. The degree of satisfaction was, however, associated with self-reported overall health among participants in this study. Muscle strength is not necessarily transferable to activity performance. This emphasizes the importance of addressing factors other than strength, i.e. the individuals’ perceived outcomes in the rehabilitation and assessments after surgery.

The major keys in surgical procedures

The following issues may serve as a checklist before, during and after surgical reconstruction of upper extremity function in tetraplegia:

1. Carefully listen to the specific activity goals expressed by the patient. Document these goals.

2. Describe possible match/mismatch between patient-prioritized goals and likelihood of reaching these goals by surgery and postoperative training.

3. Is the patient mentally, physically and socially ready to undergo the demanding surgery and rehabilitation?

4. Are other tests, treatments or arrangements necessary before surgery, i.e. pressure sore treatment, joint mobilization, muscle strengthening, home/work environment adjustments and wheelchair adaptations?

5. Perform surgery according to established, time-proven techniques with predictable outcomes. Remember that opening of the hand is equally important as grip function. Strive for optimizing control, balance, power and appearance.

6. Communicate details about surgery to rehabilitation team. Any deviations from standard?

7. Inform patient about surgery and post-training protocol (content, frequency, duration).

8. Log progress and complications (range of motion, activities, swelling, wound issues, pain).

9. Inform patient and assistants about training details after discharge from hospital (orally and in writing).

10. Follow-up at certain intervals, e.g. 3, 6 and 12 months. Assess and document perceived outcomes.

Recent trends

At the recent World Congress in Reconstructive Hand Surgery and Rehabilitation in Tetraplegia, a quite dramatic evolution of accuracy of assessments, methods and combinations of method to reconstruct hand function and outcomes was reported (Tetrahand World Congress, Nottwil, Switzerland, http://www.tetrahand2018.com/) Again, the expert panel at the congress concluded that every person who sustains a cervical spinal cord injury with tetraplegia should be examined, assessed and, based on feasibility, informed about the options of reconstruction of motor function of the hands and arms. This ambitious plan presented by the leading experts stresses the necessity of spreading the knowledge and improving the infrastructure to meet patients’ fair demands of informed discussions about surgical options for improvement of hand function. The current trend is to direct the treatment towards restoring abilities more than just functions. Of course, the available surgical treatments depend of level of lesions, i.e. the lower level of cervical spinal cord injury, the more available motors for nerve and tendon transfer (Table 1). Nevertheless, the communication with the patient and her/his caregivers and relatives is critical in order to pinpoint the exact needs of improvement in daily life activities. It is not the functional improvement from the surgeon’s or the therapist’s perspective that is important, but the patient’s priorities for controlling as many as possible of the daily routines of life. Not until this approach has been fully implemented into the preoperative assessment and goal discussion can we truly provide the service requested.

Future perspectives

Significance of a S-PIN nerve transfer

Since the reintroduction of the S-PIN nerve transfer in tetraplegia (Bertelli et al., 2010), the road map of grip reconstructions has changed to a certain degree. The tendon transfer procedure must be tailored relative to the degree and distribution of the reinnervation. For example, a partial reinnervation of the thumb extensors may not be sufficient to counteract a strong BR-FPL tendon transfer. Conversely, a fully reinnervated APL after nerve transfer makes arthrodesis of the thumb CMC joint superfluous. Also, even a reinnervated EDM of strength grade 3 allows for powering of the thumb palmar abductor APB so thumb can be actively moved along the radial side of the index (Fridén et al., 2012). This is an important ability when changing from lateral pinch to tip pinch. A reinnervation of the ECU balances the wrist by reducing the radial deviation and thus making the wrist extension stronger by allowing the ECRB to have a straighter line of action.

Significance of successful reinnervation of triceps function by transfer of axillary nerve branches to deltoid and/or teres minor muscles

Nerve transfers can effectively restore elbow extension (Bertelli and Ghizoni, 2015; van Zyl et al., 2014). Successful restoration would secure elbow stability when using the BR as a key motor in subsequent grip reconstruction. However, our patients are typically propelling manual wheelchairs and transfer with extended elbows. Therefore, the impact of denervating the shoulder external rotators on shoulder mechanics and kinematics must be studied. Excessive and uneven force distribution in the shoulder joint over time may potentially increase the risk of osteoarthrosis and pain.

Significance of rehabilitation

Most experts agree that reconstructive hand surgery in tetraplegia must not be performed without solid rehabilitation support, particularly considering the complexity of motor relearning following extensive surgeries. Several measures can be done to enhance the outcomes. For example, functional electrical stimulation (FES) has a documented influence on the muscle architecture, power output, cross-sectional area and muscle fibre type adaptation that may be beneficial in preparation for surgery (Bersch and Fridén, 2016). After surgery, electromyography-triggered stimulation can be applied to retrain the transferred muscle to perform a new function that may induce neuroplastic changes supporting the motor learning. In nerve transfers, FES testing of potential donor and recipient nerves is a simple and reliable method to determine if upper and/or lower motor neuron lesions are present.

In order to expedite the expansion of the knowledge base for combined tendon and nerve transfer strategies, synchronization of research efforts must be undertaken. The comprehensive spinal units with upper extremity reconstruction facilities play an utmost role in this development for example by designing and initiating multicentre studies with clear patient-perceived outcomes measurements.