The Surgical Restoration of Arm and Hand Function in Tetraplegic Patients

Background: There are approximately 140 000 people in Germany with spinal cord injury, with approximately 2400 new patients each year. Cervical spinal cord injuries cause, to varying degrees, weakness and impairment of everyday activities of the limbs (tetraparesis, tetraplegia).

Methods: This review is based on relevant publications retrieved by a selective search of the literature.

Results: From among 330 initially screened publications, 40 were included and analyzed. Muscle and tendon transfers, tenodeses, and joint stabilizations yielded reliable functional improvement of the upper limb. Tendon transfers improved the strength of elbow extension from M0 to an average of M3.3 (BMRC) and grip strength to approximately 2 kg. In the long term, 17–20% of strength is lost after active tendon transfers and slightly more after passive ones. Nerve transfers improved strength to M3 or M4 in over 80% of cases, with the best results overall in patients under 25 years of age who underwent early surgery (within 6 months of the accident). Combined procedures in a single operation have been found to be advantageous compared to the traditional multistep approach. Nerve transfers from intact fascicles at segmental levels above that of the spinal cord lesion have been found to be a valuable addition to the established varieties of muscle and tendon transfer. The reported long-term patient satisfaction is generally high.

Conclusion: Modern techniques of hand surgery can help suitably selected tetraparetic and tetraplegic patients regain the use of their upper limbs. Competent interdisciplinary counseling about these surgical options should be offered as early as possible to all affected persons as an integral part of their treatment plan.

There are approximately 140 000 people in Germany with spinal cord injury (SCI), with approximately 2400 new patients each year (e1, e2). For the year 2021, the German Federal Statistics Office reports 6122 inpatient cases with a primary diagnosis of spinal cord injury (ICD10-G82, International Statistical Classification of Diseases and Related Health Problems) (e3). Up to 58.7% of cases involve injury to the cervical spinal cord (C[cervical]1-Th[thoracic]1) (e4). Such injuries can be non-traumatic as a result of ischemia or tumor. More frequent causes, however, include traffic accidents, domestic falls, diving headfirst into shallow water during leisure activities, or accidents at the workplace (e5).

Although spinal cord injury can affect almost all organ systems, restoration of arm and hand function has the highest priority. In a study involving 565 subjects with tetraplegia, 77 to 92 percent expected a significant improvement in quality of life if their hand function improved (e6, e7). Strategies are now available to restore these lost functions by performing established muscle-tendon transfers and nerve transfers. The latter have found increasing use in recent years. The AWMF (Association of the Scientific Medical Societies in Germany) S2e guideline (Reg. No. 179–013, 06/2020) “Improving upper limb function in patients with cervical spinal cord injury” (e8) contains the following statement with a recommendation grade A: “Procedures to improve function should be offered to all patients with cervical SCI and performed in a multidisciplinary team setting when functional improvement is anticipated.”

However, in only a few countries (for example, Sweden, Switzerland) do patients routinely have access to interdisciplinary consultations and surgery. In Germany too, the situation regarding tetraplegic hand surgery care and the development of referral pathways to specialist centers are still in their infancy. Apart from financial aspects and the limited availability of appropriate expertise, other reasons include above all a lack of access to information for doctors, patients, and therapists, so that there is a need here for clarification and education (e9, e10, e11).

The aim of this article is to provide an overview of current concepts in hand surgery to improve upper limb function in tetraplegic patients. First of all, basic principles, indications, and contraindications for tetraplegic hand surgery procedures will be presented and then supplemented by a selective literature search.

Basic principles of tetraplegic hand surgery

Spinal cord injury results in paralysis of all motor functions below the level of injury. The functions of those muscle groups which receive their innervation from segments proximal to the level of spinal cord injury usually still remain intact. With the targeted transfer of individual functional (yet dispensable) muscles or nerve branches to the paralyzed segments, these can take over those lost, yet in part, more important distal functions. This is possible in the presence of complete or incomplete paralysis. Only those donor tendons and donor nerves are used for tendon transfer and nerve transfer whose function can be compensated by other intact muscles. In no way is one function “sacrificed” for another (e12, e13), (Table).

Table

Summary of surgical options to improve arm and hand function

Muscle/Tendon transfers

Since a single movement is often achieved by several muscles simultaneously, for example, elbow flexion by the biceps, brachialis, and brachioradialis muscles, one of these muscles (usually brachioradialis) can serve as a donor muscle, because elbow flexion is sufficiently preserved by the biceps and brachialis muscles (eVideo 1). The advantage here is that, after stable tendon attachment, these reconstructive techniques function immediately and can be subsequently exercised. The disadvantage is the need for more complex and lengthy splinting.

Figure

Figure a) Before surgery: left hand: typical position of function during everyday tasks, such as using a keyboard. C7 tetraplegia secondary to a fracture-dislocation of cervical vertebrae 6/7 with a left tetraplegic hand. Active flexion of the fingers and thumb, thumb opposition, and functional grasping sequences produced by the intrinsics are not possible. b), c), d) After surgery: Significantly improved resting position of the hand, improved coordination, pinch grip and power three months after combined reconstruction of the left extensor and flexor phase by multiple tendon transfers (so-called alphabet procedure). This involved, amongst other things, imitating intrinsic hand function using a House procedure, and reconstruction of active finger flexion via a transfer of the brachioradialis muscle to flexor digitorum profundus and of opposition using an indicis transfer.

eFigure

PRISMA search strategy for identifying trials using databases and registers

Nerve transfers

Over recent years, nerve transfers have increasingly become established procedures in tetraplegic hand surgery. They exploit the spontaneous ability of peripheral nerves to regenerate after injury. Here too, dispensable, intact motor nerve fascicles are transferred from above the level of cervical injury to motor nerve branches whose target muscles are no longer under voluntary control due to the spinal cord injury and are therefore paralyzed (eVideo 2). The advantage lies in the reinnervation of the original target muscles together with the restoration of physiological movement patterns. The disadvantage lies in the long reinnervation time with less predictable outcomes.

Supplementary corrective procedures

Tenodeses or joint fusions can address restrictive malpositions and instabilities.

Painful contractures can be corrected by tendon release, lengthening, and transfer (e14). Hyperselective neurectomy can significantly reduce the tone of spastic paralysis by excising most of the fascicles of the involved motor nerves at the point of entry into the target muscle, while still preserving muscle strength (e15).

Box

Conclusions for clinical practice

Preconditions, indications,
and contraindications

The indication for surgery is determined by the level of injury and the severity of spinal cord damage using an international classification. A crucial factor is the number of dispensable muscles which are capable of movement against resistance (power grade equal to, or greater than, M4 according to the British Medical Research Council – BMRC [e16]), (eBox) and are therefore transferable.

eBox 1

Methods

eBox 2

British Medical Research Council (BMRC)

Other preconditions include good passive joint mobility and essentially complete neurological recovery, emotional stability of the patient, and a realistic assessment of the anticipated outcome of treatment. These preconditions are not usually met until initial specific treatment for the spinal cord injury has been largely completed (after approximately four to six months).

There are limitations and surgical contraindications for very high spinal cord injuries (C4) in which suitable donor tissue is no longer available for nerve or tendon transfers, in situations with stiff joints, pressure sores, or acute infections (for example, urinary tract infection), or unrealistic expectations of those involved.

Major spasticity used to be considered a contraindication, but nowadays reliable procedures are available to correct contracture and reduce spasticity. Appropriate assessment tools are also available and mandatory for making an exact evaluation of realistic patient goals (for example: COPM, Canadian Occupational Performance Measure) (e13).

Optimal timing

Choosing the correct time for surgery plays a substantial role towards the success of the procedure. Muscle-tendon transfers are still possible even years after the initial spinal cord injury. The earliest possible time point should be chosen so that spontaneous neurological recovery is complete and functionality of the muscles and tendons to be transferred can be confidently assessed.

It is a different situation with nerve transfers. These procedures must be undertaken before degeneration of the motor endplates of the target muscles ensues. They most reliably achieve a practical return of function within the first year after injury (1, 2). Patients who are in principle suitable should therefore undergo assessment and receive advice in this respect from an experienced team (comprising hand surgery, paraplegiology, physiotherapy and occupational therapy) within approximately six months (e13).

Relearning processes

The new target movements are subject to relearning via processes of central cortical plasticity or reorganization. To our knowledge to date, existing but previously silent interneuronal connections are unmasked (e17) for this purpose and representative cortical areas are shifted (e18). Most likely, not individual muscle functions, but rather the target movement itself is engrammed in cortical structures. Targeted postoperative rehabilitation training with visual feedback is required for this. This gradual shift of motor control usually takes a few weeks (e18).

Methods

The techniques presented here raise the pertinent question of the effectiveness of, and indication for, the new types of nerve transfers in comparison with traditional tendon transfers. In order to answer this question, a selective literature search was conducted using PubMed and based upon the PRISMA (Preferred Reporting Items for Systematic Review and Meta Analysis) guidelines (e19) (see eBoxes 3 and 4 for search strategy and inclusion criteria).

eBox 3

(MeSH Terms)

eBox 4

Formal results of the search strategy

Results

The formal results of the literature search are presented separately in the supplementary section.

The samples presented in the 40 selected articles (eTable) are relatively small; on average, 39.5 ± 53.7 patients were reported on for tendon transfers, while the group size for the reported nerve transfers was even smaller with an average of 10.4 ± 3.7 patients. The group size for combined procedures was 19.5 ± 6.5 patients. An average of 32.5 ± 30.9 limbs were treated with tendon transfers, 12.2 ± 3.2 limbs with nerve transfers, and 22 ± 4.8 using combined procedures.

eTable

Evaluation of the included literature citations obtained through PRISMA guidelines

Nerve transfers, including double and triple transfers, were used for elbow and wrist extension as well as hand opening and closure. The main procedures used for nerve transfer were transposition of the supinator branch to the posterior interosseous nerve (S-PIN transfer) and the motor branch of the brachialis muscle to the anterior interosseous nerve (Br-AIN transfer).

Depending on the level of injury, combinations of the following procedures were noted for tendon transfer: reconstruction of elbow function by deltoid-to-triceps transfer or biceps-to-triceps transfer; reconstruction of wrist extension by BR-to-ECRL/B transfer (BR = brachioradialis, ECRL/B = extensor carpi radialis longus/brevis), extensor tendon tenodesis, reconstruction of intrinsic hand function by tenodesis (House procedure) and the Zancolli lasso procedure, thumb carpometacarpal joint fusion, reconstruction of fist closure by FDP attachment (flexor digitorum profundus), BR-to-FDP or PT-to-FDP transfers (PT = pronator teres), and FCR-to-FPL transfers (FCR = flexor carpi radialis, FPL = flexor pollicis longus), and other variations of these procedures.

Analysis of the time of surgery with respect to the time of accident showed that patients who underwent tendon transfer had suffered SCI longer and had undergone surgery on average 76.6 ± 53.6 months after SCI. In contrast, nerve transfer was performed after 28.2 ± 23.5 months. Combined procedures were conducted after 9.8 ± 0.9 months.

The follow-up period was 42.1 ± 47.3 months for tendon transfers, 15.6 ± 8.3 months for nerve transfers, and 24 months for combined procedures.

A large number of assessment tools were used as outcome parameters (eBox 5).

eBox 5

Outcome parameters

An average improvement in elbow extension from power grade M0 to an average of M3.3 was accomplished by tendon transfer, with a postoperative grip strength of approximately 2 kg.

In over 80% of cases, nerve transfers achieved a postoperative improvement in power grades to M3/M4, with the best overall results being in young patients (under 25 years of age) who were operated on early (up to six months after injury). The prospective case series presented by van Zyl et al. (1) in 2019 demonstrated that early nerve transfer for cervical spinal cord injury was safe and effective in 16 patients (27 upper limbs). Functional scores showed significant improvement of function. The ARAT score improved from 15.5 to 32.0 (p = 0.0015) for selective nerve transfers, while the GRT score rose from 29.8 to 89.3 (p = 0.0010). The ARAT score increased from 18.0 to 37.5 (p = 0.012) for combined nerve and tendon transfers, and the GRT score rose from 39.4 to 142.9 (p = 0.017). Four (8%) of a total of 50 nerve transfers failed (failed innervation) during the 24-month follow-up; there were no minor complications from the surgical procedure itself and no reduction in the strength of donor functions. This study emphasizes the importance of the combination of nerve and tendon transfers.

An analysis of reported complications after nerve transfer mentions mild persistent thumb paresthesia in one patient (2). No other complications after nerve transfer were reported, in particular, there was no weakness in preoperative function as a result of the nerve transposition. With significantly higher patient numbers having undergone tendon transfer, five studies reported postoperative infection (3, 4, 5, 6, 7) and five studies (3, 5, 6, 7, 8) mentioned rupture or loosening of the transposed tendon. Two studies reported adhesions with subsequent need for tenolysis (3, 6). One patient demonstrated no improvement after tendon transfer, but no further details were provided (9). Three studies reported postoperative hematoma formation (4, 7, 10), and the wrist flexors were weaker in two studies after tendon transfer (3, 11). One article reported non-union of the thumb CMC joint fusion (6), and in one study fusion of the thumb IP joint was required after tendon transfer due to hyperflexion following brachioradialis to FPL (flexor pollicis longus) transfer (3).

Risk of bias at the single-study level

All the included studies presented bias risks:

• (Self-)selected study population
• No randomization, no control condition, no blinding
• No details about patients who refused participation or surgery.

Discussion

The statements presented in the AWMF guideline (e8) emphasize the importance of procedures to improve upper limb function in quadriplegic patients and at the same time point to the necessary interdisciplinary deployment of such treatment teams in specialist centers.

Tetraplegic hand surgery is undergoing a period of change as a result of modern surgical treatment options provided by nerve transfers and the increased attention associated with them. However, there are considerable country-specific differences in the awareness of these treatment options and generally in the availability of centers offering this type of treatment (e9).

In contrast, there are positive reports of operated patients who speak of considerable improvement in their quality of life. These operated patients summarize their improvements as “increased independence from the help of others“, including autonomy, self-confidence, and more active interpersonal interactions. Psychological aspects include the feeling of being able to cope better with everyday life, being less dependent on assistance and the environment, and having more self-efficacy in hand control (12). Mohammed et al. reported enhanced quality of life in 84% of patients after tendon transfer procedures to improve arm and hand function (28). Using a validated questionnaire, 95% of 58 Swedish patients reported that they had benefited on the whole from the surgical rehabilitation; 86% felt a positive impact on their lives from surgery (13). Sustainability of functional improvement was demonstrated over periods of more than ten years. In detail, 11 years after surgery a consistent to somewhat reduced grip strength (around 5 to 14%) was observed for active tendon transfers and a more significant reduction in strength of 40 to 51% for tenodesis (14). Vastamäki (15) reports on 24-year results and demonstrated similar loss of strength of 16% for elbow extension and 21% for key pinch. Nevertheless, these procedures are felt to have an advantageous and worthwhile impact on quality of life and satisfaction. Eighty-three percent of a Swedish cohort reported they were highly satisfied overall with the surgical procedure, 72% highly satisfied especially with improvements in daily activities, and 31% with respect to their profession (16). Patient-reported satisfaction in these three sub-areas remained at this level over the long term, with 77.1% stating they were willing to undergo the procedure again (17).

In this review, the results obtained for the specific question regarding the value of nerve and tendon transfers indicate a reliable improvement of those most important upper limb functions. A decisive factor for the success of such interventions is the indication for surgery based on a multidisciplinary approach, in which the available techniques and their timing need to be adapted to the individual patient. Validated assessment tools should be applied to document prospective patient aims. Limitations regarding the indication for surgery (high paralysis, elapsed time, stiff joints, patient expectation) must be clearly assessed by the doctors and explained to those involved. Equally important is it to explain the anticipated outcome of surgery. A power grade of M3 is indeed a significant improvement over a preoperative power grade of M0 and, as explained, very worthwhile from the patient’s point of view, but complete power against maximum resistance is neither achievable nor to be expected.

At this point, possible alternatives to surgical procedures for improving function should also be mentioned. For example, custom-made splints or supports can produce good wrist stabilization in many cases and allow common everyday activities. If the patient finds these adequate, then surgical stabilization can be dispensed with. If, however, the patient wants additional active function in the form of finger flexion and extension as well as independence from aids, then surgery may be offered.

Patients can be relieved of the worry they often express concerning the risks of surgery or even deterioration in comparison with the situation before the operation. The complications cited in the literature were very rare and reliably controllable.

Nevertheless, a possible bias in the reported results must be addressed at this point. The very good and homogeneous overall results are predominantly published by larger spinal cord injury centers with years of experience in this field. It cannot be ruled out that the procedures performed in small institutions were possibly unsuccessful and not published.

Acknowledgments

Our sincere thanks go to Dr. Ralf Bruckmoser for producing the 3D-animated videos and to Prof. Dr. K. Schwerdtfeger and Dr. A. Stolle for their support in assessing the literature.

Conflict of interest statement

The authors declare that no conflict of interest exists.

Manuscript received on 24 September 2022, revised version accepted on 23 May 2023.

Translated from the original German by Dr Grahame Larkin MD

Corresponding author
Prof. Dr. med. Leila Harhaus
Department of Hand Surgery, Peripheral Nerve Surgery and Rehabilitation

Department of Hand and Plastic Surgery

Heidelberg University

BG Trauma Center Ludwigshafen

Ludwig-Guttmann-Strasse 13

67071 Ludwigshafen, Germany

Cite this as:
Harhaus L, Aman M, Pennekamp A, Weidner N, Panzram B, Gohritz A: The surgical restoration of arm and hand function in tetraplegic patients.
Dtsch Arztebl Int 2023; 120: 627–32. DOI: 10.3238/arztebl.m2023.0141

►Supplementary material

eReferences, eMethods section, eTables, eFigures, eBox, and eVideos:
www.aerzteblatt-international.de/m2023.0141

cme plus

This article has been certified by the North Rhine Academy for Continuing Medical Education. Participation in the CME certification prgram is possible over the internet: cme.aerzteblatt.de. The deadline for submission is 21 September 2024.

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