A Case of Spaghetti Wrist: Approach to an Extensive Volar Forearm Laceration in the ED

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Medical Student Clinical Pearl by Krystal Stewart

 

 

MD Candidate, Class of 2024

Dalhousie University

Reviewed by Dr. F MacKay

Copy Edited by Dr. J Vonkeman

Pdf Download: EMSJ A Case of Spaghetti Wrist: Approach to an Extensive Volar Forearm Laceration in the ED

 

Case Presentation

A 13-year-old male presents to the Emergency Department by ambulance, with a deep laceration to his distal volar forearm. The injury occurred at a friend’s house, after tripping on a bong with the shattered glass lacerating his left wrist. The patient was intoxicated by cannabis at the time of arrival and experienced bouts of age regression while attempting to assess and treat him. He is otherwise healthy, with no significant past medical history and is not taking any regular medications. This was an isolated injury; no other lacerations were found on the body, and blood loss at the site of injury was well controlled by the time of arrival at the ED.

On physical examination, pertinent findings consist of the ulnar arterial pulse not being palpable, no sensation throughout the ulnar nerve distribution of the hand, and the flexor carpi ulnaris tendon is visibly torn. Capillary refill was normal, with perfusion being provided solely by the radial artery – which remains intact. Motor examination of the hand was difficult to assess due to patient’s intoxicated state and pain level. The patient felt he was unable to move his hand but was able to wiggle his thumb and index finger.

The on-call plastic surgeon was consulted to assess the defect. The wound was washed out with saline and briefly explored under local anesthetic by the surgeon. Subsequently, the wound was closed with simple interrupted sutures and a volar slab splint was placed on the hand and forearm for temporary stability. The patient was admitted overnight to the pediatric floor to await further exploration in the OR and reparation of the ulnar artery, ulnar nerve, and several flexor tendons.

Anatomical Context

Figure 1: Carpal tunnel anatomy of the volar wrist.1

Clinical Approach

A deep laceration of the distal volar forearm may otherwise be known as the “spaghetti wrist,” due to the number of potential structures that could require repair, including tendons, nerves, and vessels. This term came about from the appearance of lacerated tendons overlying the red background of muscle.2 There lacks a unified classification system for this term in the literature, thus defining a volar forearm laceration and its level of severity as a spaghetti wrist injury is more subjective – with an arbitrary sum of structures lacerated.3

First begin by assessing the patient for hemodynamic instability, if bleeding – apply direct pressure, if it continues a temporary tourniquet may be needed.2 It is important to evaluate for hemorrhagic shock and resuscitation prior to assessment of the hand.2

Vascular status of the hand can be assessed with capillary refill or Doppler ultrasound to each fingertip.2 If the hand is considered well perfused and bleeding is well controlled, surgical exploration can be delayed, as it will take several days for cut tendons, nerves, and vessels to retract.2 If there is concern for arterial laceration, palpation for radial and ulnar pulses would be valuable.

The next important assessment is a focused sensory and motor examination of the hand. Lightly touch at the three sensory areas that represent the cutaneous radial, median ulnar innervation of the hand as demonstrated in Figures 2 and 3.2 Evaluating the extrinsic and intrinsic hand muscle innervation requires a focused motor examination, as demonstrated in Figure 4.2 Have the patient demonstrate a series of hand gestures, the “OK” sign using the index finger and the thumb represents the muscles innervated by the median nerve.2 By abducting the digits, this represents the muscles innervated by the ulnar nerve.2 Lastly, demonstrating a “thumbs up” sign represents the muscles innervated by the radial nerve.2 If there is lack of sensation at a particular sensory distribution and/or lack of ability to demonstrate those representative hand gestures for extrinsic and intrinsic muscle innervation, it should be noted that the associated nerve(s) may be damaged.

To evaluate for any associated injuries to bone, muscle, tendon or ligament, gentle manipulation and palpation is required, along with assessing passive and active range of motion.2 It may also be valuable to assess if there is any ulnar or radial deviation of the wrist.2

 

 

Figure 2: Cutaneous innervation of the volar hand.2

 

Figure 3: Cutaneous innervation of the dorsal hand.2

 

Figure 4: Motor examination of the hand. I: Median nerve, II: Ulnar nerve, III: Radial nerve.2

Management 

Important information to gather on clinical history include the use of anticoagulants, diagnosis of advanced liver disease or diabetes. As the former two impair hemostasis, and the latter may impair wound healing.2 Broad spectrum IV antibiotics may be warranted if the wound is largely contaminated or extensive in size.2 There is a potential risk of contracting tetanus based on the mechanism of injury, thus it is important that the patient has tetanus prophylaxis.2,4An X-ray of the hand and forearm may be necessary if suspicion of a bony fracture.

A consult should be sent to the Plastic Surgery service for further management, including surgical exploration and reparation of any lacerated nerves, tendons, and vessels. These structures begin to retract after injury; thus, it is important that reparation is done within two weeks of injury. If plastic surgeon on call is planning to see the patient in clinic, have the forearm and wrist dorsally splinted at the position of safe immobilisation – wrist in 0-30 degree of extension, MCP joints in 70-90 degrees of flexion and IP joints in full extension.5,6 Once the repair is completed and appropriate hand immobilization has been achieved, the patient should see a designated occupational hand therapist for further patient education and hand rehabilitation.

Prognosis 

The road to recovery largely depends on the patient’s willingness to undergo post-operative rehabilitation and adhere to the regimens set forth by the surgeon and the occupational hand therapist. Age and smoking status may also impact neurologic recovery.5 Nerve regrowth from the site of laceration is a slow process, with approximately 1 mm in growth daily.5 Recovery tends to be functional, with less emphasis on perfection. Ulnar innervation tends to be less predictable in regrowth of intrinsic muscles.5 Possible long-term sequelae include stiffness, neuropathic pain, and cold intolerance.5

Key Points

  • If the hand is de-vascularized, immediate emergency surgery is essential.5
  • If the injury was self-inflicted, a consult to psychiatry is recommended once medically cleared.5
  • Negative prognostic factors include increasing age, low education level, presence of a crush injury.7

Complications

With complex volar forearm lacerations there is the risk of developing acute compartment syndrome post-injury. Diagnosis of acute compartment syndrome is achieved clinically, with signs of swollen and taut muscle compartment(s), pain out of proportion to the injury, or severe pain with passive digital extension.2 Neurological deficits present as a late feature of the syndrome, including paresthesia, paresis and then paralysis.2 Paresthesia is an indicative feature of early nerve ischemia.2 The intra-compartmental absolute pressure may also be measured if suspicious of compartment syndrome – an emergent forearm fasciotomy should be done if greater than or equal to 30 mmHg.2

Post-operative complications may include major deformity of hand due to clawing, ‘anesthetic hands,’ as well as neuromas – being the most cited complication.3 The former two are most likely due to the initial injury rather than a complication from the surgery itself.3 The term ‘clawing’ refers to an ulnar nerve palsy, where the hand will resemble that of a claw hand.8

 

Conclusion

While the Spaghetti Wrist terminology does not have a severity scale, it is intuitively known to be an emergent case with the need for prompt management. Whether the cause of injury was accidental or self-inflicted, the same steps must be taken to ensure that the function of the hand can be salvaged – as the impact on the patient’s physical function and psychological health could be enormous if not managed correctly.

References

  1. Hansen JT, Netter FH. Netter’s Clinical Anatomy. 2nd Philadelphia, PA: Saunders/Elsevier; 2010.
  2. Thai JN, Pacheco JA, Margolis DS, et al. Evidence-based Comprehensive Approach to Forearm Arterial Laceration.West J Emerg Med. 2015;16(7):1127-1134. doi:10.5811/westjem.2015.10.28327
  3. Koshy K, Prakash R, Luckiewicz A, Alamouti R, Nikkhah D. An Extensive Volar Forearm Laceration – The Spaghetti Wrist: A Systematic Review.JPRAS Open. 2018;18:1-17. Published 2018 Jul 11. doi:10.1016/j.jpra.2018.06.003
  4. Bae C, Bourget D. Tetanus. In:StatPearls. Treasure Island (FL): StatPearls Publishing; August 19, 2022.
  5. Meals CG, Chang J. Ten Tips to Simplify the Spaghetti Wrist.Plast Reconstr Surg Glob Open. 2018;6(12):e1971. Published 2018 Dec 12. doi:10.1097/GOX.0000000000001971
  6. Dobson P, Taylor R, Dunkin C. Safe splinting in hand surgery.Ann R Coll Surg Engl. 2011;93(1):94. doi:10.1308/003588411×12851639108033
  7. De M, Singhal M, Naalla R, Dave A. Identification of Prognostic Factors in Spaghetti Wrist Injuries.J Hand Surg Asian Pac Vol. 2021;26(4):588-598. doi:10.1142/S2424835521500569
  8. Lane R, Nallamothu SV. Claw Hand. In:StatPearls. Treasure Island (FL): StatPearls Publishing; January 8, 2023.
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